Vascular Plants

Includes all flowering plants, conifers, ferns and fern-allies.


Browse by scientific name:
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Scientific names beginning with A:
105 genera
372 species, 112 subspecies and varieties
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Index to genera:
Abies, Abronia, Abutilon, Acer, Achillea, Achlys, Achnatherum, Acmispon, Aconitum, Aconogonon, Acorus, Actaea, Adelinia, Adenocaulon, Adiantum, Adonis, Aegilops, Aegopodium, Aesculus, Agastache, Ageratina, Agoseris, Agrimonia, Agropogon, Agropyron, Agrostemma, Agrostis, Ailanthus, Aira, Ajuga, Alcea, Alhagi, Aliciella, Alisma, Alliaria, Allium, Allotropa, Alnus, Alopecurus, Alstroemeria, Alyssum, Amaranthus, Amauropelta, Ambrosia, Amelanchier, Ammannia, Ammophila, Amorpha, Amphiscirpus, Amsinckia, Anaphalis, Anchusa, Andromeda, Androsace, Anemone, Anethum, Angelica, Anisocarpus, Antennaria, Anthemis, Anthoxanthum, Anthriscus, Anticlea, Antirrhinum, Apera, Aphanes, Aphyllon, Apium, Apocynum, Aquilegia, Arabidopsis, Arabis, Aralia, Arbutus, Arceuthobium, Arcteranthis, Arctium, Arctostaphylos, Arenaria, Aristida, Armeria, Armoracia, Arnica, Aronia, Arrhenatherum, Artemisia, Arum, Aruncus, Asarum, Asclepias, Askellia, Asparagus, Asperugo, Aspidotis, Asplenium, Astragalus, Athyrium, Athysanus, Atocion, Atriplex, Atropa, Aubrieta, Aucuba, Avena, Azolla
Abies amabilis – Pacific silver fir
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to northern California.
Habitat: Mostly at 1000-4000 feet elevation in the mountains.
Origin: Native
Growth Duration: Perennial
Abies grandis – grand fir
Distribution: Occurring on both sides of the Cascades crest in Washington; Vancouver Island, British Columbia to California, east to Idaho and Montana.
Habitat: Coniferous forests, from sea level to mid-elevations in the mountains.
Origin: Native
Cones: May-June
Growth Duration: Perennial
Abies lasiocarpa – alpine fir, subalpine fir
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains.
Habitat: Subalpine to alpine slopes, where commonly in krumholtz form.
Origin: Native
Cones: June-July
Growth Duration: Perennial
• ssp. bifolia – Rocky Mountain subalpine fir
• ssp. lasiocarpa – subalpine fir
Abies procera – noble fir
Distribution: Occurring chiefly west of the Cascades crest in Washington; northern Washington to the Siskiyou Mountains in northern California.
Habitat: Deep forests where there is sufficient moisture, moderate to fairly high elevations.
Origin: Native
Growth Duration: Perennial
Abronia latifolia – yellow sand verbena
Distribution: Occurring west of the Cascades crest in Washington along the coast; Vancouver Island, British Columbia to California.
Habitat: Coastal beaches and sand dunes.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
Abronia mellifera – honey-scented sandverbena, white sand verbena
Distribution: Distributed east of the Cascades in Washington in the Columbia Basin and along the Snake River; north-central Oregon, southeastern Oregon and adjacent Idaho, southeastern Idaho and adjacent Wyoming.
Habitat: Dunes and sandy soil at low elevations.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
• var. mellifera
Abronia umbellata – pink sandverbena
Distribution: Occurring west of the Cascades crest along the outer coast in Washington; British Columbia to Baja California.
Habitat: Coastal sandy beaches and adjacent dunes.
Origin: Native
Flowers: May-September
Growth Duration: Perennial
• var. acutalata – sand verbena
• var. breviflora – sand verbena
Abutilon theophrasti – velvetleaf
Distribution: Occurring in scattered locations on both sides of the Cascades crest in Washington; British Columbia to California, east across North America to the Atlantic Coast.
Habitat: Roadsides, fields, wastelots, and other disturbed open places.
Origin: Introduced from Eurasia
Flowers: July-August
Growth Duration: Annual
Acer campestre – field maple, hedge maple
Distribution: Occurring west of the Cascades crest in Washington; Washington to California, also in scattered locations in eastern North America.
Habitat: Fields, forest edges, and other disturbed areas where escaped from cultivation
Origin: Introduced from Eurasia
Flowers: April-May
Acer circinatum – vine maple
Distribution: Occurring chiefly west of the Cascades crest in Washington; Alaska to northern California.
Habitat: Moist woods from sea level to mid-elevations in the mountains.
Origin: Native
Flowers: March-June
Growth Duration: Perennial
Acer glabrum – Rocky Mountain maple
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains and Great Plains.
Habitat: Moist woods from sea level to mid-elevations in the mountains.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
• var. douglasii – Douglas maple
Acer macrophyllum – big-leaf maple
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to southern California.
Habitat: Moist woods from sea level to middle elevations in the mountains.
Origin: Native
Flowers: March-June
Growth Duration: Perennial
Acer negundo – box elder, box elder maple
Distribution: Occurring chiefly east of the Cascades in Washington; widely distributed throughout much of North America.
Habitat: Occasionally escapes from cultivation, chiefly in disturbed areas or riparian zones.
Origin: Introduced from eastern North America, escaped from cultivation
Flowers: April-June
Growth Duration: Perennial
Acer platanoides – Norway maple
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to Oregon, east to Idaho and Montana; invasive in eastern North America.
Habitat: Forest edge, riparian zones, fields, and other disturbed areas where escaped from cultivation.
Origin: Introduced from Europe
Flowers: April-May
Growth Duration: Perennial
Acer pseudoplatanus – sycamore maple
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia to Oregon, east to Montana, also in eastern North America.
Habitat: Forest edge, fields, and other disturbed areas where escaped from cultivation.
Origin: Introduced from Europe
Flowers: April-May
Growth Duration: Perennial
Acer saccharinum – silver maple
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east to Idaho and Montana, also in central and eastern North America where native.
Habitat: Riparian corridors, moist bottomlands, and other areas near water, often disturbed.
Origin: Introduced from central and eastern North America
Flowers: March-April
Growth Duration: Perennial
Achillea millefolium – milfoil, yarrow
Distribution: Widely distributed on both sides of the Cascades crest in Washington; Alaska to California, east to the Atlantic Coast; circumboreal
Habitat: Common in open, dry to somewhat moist areas from low to high elevations; tolerant of disturbance.
Origin: Both native and introduced populations
Flowers: February-October
Growth Duration: Perennial
Achillea ptarmica – pearl yarrow
Distribution: Reported from Washington but no specimens seen; Alaska to Oregon, east in scattered locations across North America to the Atlantic Coast.
Habitat: Roadsides, wastelots, and other disturbed open areas where occasinally escaping from cultivation.
Origin: Introduced from Eurasia
Flowers: May-August
Growth Duration: Annual, Perennial
Achlys californica – deer's-foot
Distribution: On both sides of the Cascades and in the Olympic Mountains in Washington; British Columbia to California.
Habitat: Moist areas in deep woods to open parks.
Origin: Native
Flowers: April-July
Growth Duration: Perennial
Achlys triphylla – deerfoot, vanillaleaf
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California.
Habitat: Moist areas in deep woods to forest openings.
Origin: Native
Flowers: April-July
Growth Duration: Perennial
• ssp. triphylla – deerfoot, vanillaleaf
Achnatherum hendersonii – Henderson's needlegrass
Distribution: Occurring east of the Cascades crest in Douglas, Kittitas, and Yakima counties; central Washington to Jefferson County, Oregon.
Habitat: Dry, rocky, shallow soil, in sagebrush desert or ponderosa pine forest openings.
Origin: Native
Flowers: May-June
Growth Duration: Perennial
Achnatherum hymenoides – Indian ricegrass
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Great Plains.
Habitat: Grasslands, desert plains, and foothills, especially on rocky or sandy soil.
Origin: Native
Flowers: May-June
Growth Duration: Perennial
Achnatherum lemmonii – Lemmon's needlegrass
Distribution: Occurring chiefly east of the Cascades crest in Washington; southern British Columbia to California, east to the Rocky Mountains.
Habitat: Grassy balds, prairies, sagebrush grasslands, and ponderosa pine forest, from the lowlands to middle elevations in the mountains.
Origin: Native
Flowers: May-June
Growth Duration: Perennial
• ssp. lemmonii
Achnatherum nelsonii – Nelson's needlegrass
Distribution: Occurring chiefly east of the Cascades crest in Washington; Yukon Territory to California, east to the northern Great Plains and Colorado.
Habitat: Moist to mesic, montane to subalpine meadows and open forest.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
• ssp. dorei – Nelson's needlegrass
• ssp. nelsonii – Nelson's needlegrass
Achnatherum occidentale – common western needlegrass
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Grassland, sagebrush desert, and coniferous forests from low to middle elevations.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
• ssp. californicum – California needlegrass
• ssp. pubescens – western needlegrass
Achnatherum richardsonii – Richardson's ricegrass
Distribution: Occurring east of the Cascades crest in Washington; Alaska to northeastern Oregon, east to the Canadian Great Plains and south in the Rocky Mountains to Colorado.
Habitat: Sandy and gravelly sites in grassland, open forest, and sagebrush grassland.
Origin: Native
Flowers: June-July
Growth Duration: Perennial
Achnatherum thurberianum – Thurber's ricegrass
Distribution: Occurring east of the Cascades crest in Washington; south-central British Columbia to California, east to Montana, Wyoming, and Colorado.
Habitat: Sagebrush grassland and ponderosa pine forest.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Acmispon americanus – American bird's-foot trefoil
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Rocky Mountains, south to Mexico.
Habitat: Chiefly in sandy to rocky, exposed or wooded areas, more common at low elevations
Origin: Native
Flowers: April-September
Growth Duration: Annual
• var. americanus – American bird's-foot trefoil
Acmispon denticulatus – riverbar bird's-foot-trefoil
Distribution: Occurring on both sides of the Cascades in Washington; southern British Columbia to California, disjunct in southern Idaho and southwestern Utah.
Habitat: Sandy to rocky soil in open areas at low to moderate elevations.
Origin: Native
Flowers: April-June
Growth Duration: Annual
Acmispon nevadensis – Nevada bird's-foot trefoil, Nevada deervetch
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia south to California, east to Idaho and Nevada.
Habitat: Open, disturbed areas including road cuts, balds, grasslands, and forest edges at low to moderate elevations.
Origin: Native
Flowers: May-June
Growth Duration: Perennial
• var. nevadensis – Nevada deervetch
Acmispon parviflorus – small-flowered bird's-foot trefoil
Distribution: Occurring chiefly west of the Cascades crest and east in the Columbia River Gorge in Washington; British Columbia to California.
Habitat: Open slopes and sandy flats, seashore into the mountains.
Origin: Native
Flowers: April-September
Growth Duration: Annual
Aconitum columbianum – Columbian monkshood
Distribution: Occurring chiefly east of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains.
Habitat: Moist woods and meadows, moderate to subalpine elevations.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
• ssp. columbianum – Columbian monkshood
Aconogonon davisiae – Newberry's fleeceflower, Davis' knotweed, Davis's knotweed
Distribution: Occurring on both sides of the Cascades crest in Washington; Washington to California.
Habitat: Slopes and ridges in the subalpine and alpine.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
Aconogonon phytolaccifolium – alpine fleeceflower
Distribution: East of the Cascades in Washington; Alaska south to the Sierra Nevada of California, east to Idaho and western Montana.
Habitat: Subalpine to alpine ridges, meadows and talus slopes.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
• var. phytolaccifolium – poke knotweed
Acorus americanus – American sweetflag, several-vein sweetflag
Distribution: Very limited distribution in Washington along eastern border with Idaho; widely distributed throughout northern half of North America from Alaska to Newfoundland.
Habitat: Wetlands, lake margins, and riparian zones.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Acorus calamus – sweet flag
Origin: Introduced from Eurasia
Growth Duration: Perennial
Actaea elata – tall bugbane
Distribution: Occurring west of the Cascades crest and in the Columbia River Gorge in Washington; British Columbia to Oregon.
Habitat: Moist, shady woods at low elevations.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
• var. elata – tall bugbane
Actaea laciniata – cut-leaved bugbane, Mt. Hood bugbane
Distribution: Occurring west of the Cascades crest in southwestern Washington; southwestern Washington to adjacent northwestern Oregon.
Habitat: Moist woods at middle elevations in the mountains.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Actaea rubra – baneberry
Distribution: Widely distributed on both sides of the Cascades crest in Washington; Alaska to California, east to the northern Great Plains, Great Lakes region, and northeastern North America.
Habitat: Moist woods and streambanks from low elevations to middle elevations in the mountains.
Origin: Native
Flowers: April-July
Growth Duration: Perennial
Adelinia grandis – Adeline's hound's-tongue, Pacific hound's-tongue, grand hound
Distribution: Occurring west of the Cascades crest and in the Columbia River Gorge in Washington; Washington to California.
Habitat: Forest openings and meadows at low to moderate elevations.
Origin: Native
Flowers: April-May
Growth Duration: Perennial
Adenocaulon bicolor – pathfinder, trailplant
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east the northern Rocky Mountains, northern Great Plains, and Great Lakes region.
Habitat: Moist, shady woods at low to middle elevations.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
Adiantum aleuticum – maidenhair fern, northern maidenhair fern
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east sporadically to the Rocky Mountains, also in the Great Lakes region and northeastern North America.
Habitat: Moist woods and streambanks, from low to middle elevations in the mountains.
Origin: Native
Growth Duration: Perennial
• var. aleuticum – Aleutian maidenhair fern, western maidenhair fern
Adonis aestivalis – summer pheasant's-eye
Distribution: Occurring east of the Cascades crest in Washington; central Washington to California, east to Montana, Idaho, and Utah.
Habitat: Disturbed areas.
Origin: Introduced from Europe
Flowers: May-July
Growth Duration: Annual
Aegilops cylindrica – jointed goatgrass
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east across most of the United States to the Atlantic Coast.
Habitat: Waste ground and roadsides; a troublesome weed in wheat.
Origin: Introduced from southern Europe
Flowers: May-July
Growth Duration: Annual
Aegopodium podagraria – bishop's goutweed
Distribution: Occurring in scattered locations west of the Cascades crest in the Puget Trough in Washington; southern British Columbia to Oregon, also in eastern North America.
Habitat: Disturbed forest understory and edge, where often dumped as garden waste.
Origin: Introduced from Eurasia
Flowers: May-July
Growth Duration: Perennial
Aesculus hippocastanum – horse-chestnut
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia to Oregon, also in central and eastern North America.
Habitat: Disturbed forested areas, particularly in urban and suburban areas where the species is planted as a street tree.
Origin: Introduced from Europe
Flowers: May-June
Growth Duration: Perennial
Agastache occidentalis – western giant-hyssop
Distribution: East slopes of the Cascades, Chelan to Yakima Counties, Washington; south to Oregon.
Habitat: Dry, open, often rocky slopes at low to moderate elevations.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Agastache urticifolia – nettle-leaf giant-hyssop
Distribution: East of the Cascades in Washington; British Columbia to California, east to Colorado.
Habitat: Dry open slopes and draws, foothills to mid-elevations in the mountains
Origin: Native
Flowers: May-August
Growth Duration: Perennial
• var. urticifolia – nettle-leaf giant-hyssop
Ageratina occidentalis – western boneset, western snakeroot
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to Montana, Utah, and Nevada.
Habitat: Rocky places at various altitudes.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Agoseris ×agrestis – field agoseris
Origin: Native
Agoseris apargioides – seaside agoseris
Distribution: Occurring west of the Cascades crest in Washington along the outer coast. Washington to California.
Habitat: Coastal dunes and beach heads.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
• var. maritima – seaside agoseris
Agoseris aurantiaca – orange agoseris
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains, Great Plains, and Quebec.
Habitat: Meadows and forest openings at from middle elevations to the alpine.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
• var. aurantiaca – orange agoseris, slender agoseris
• var. carnea – pink agoseris
Agoseris ×elata – tall agoseris, tall goat-chicory
Distribution: Occurring on both sides of the Cascades crest in Washington; south-central British Columbia to California.
Habitat: Meadows and open woods, from the valleys to middle elevations in the mountains.
Origin: Native
Flowers: June-July
Growth Duration: Perennial
Agoseris glauca – pale agoseris, short-beaked agoseris
Distribution: Occurring chiefly east of the Cascades crest in Washington; Yukon Territory to California, east to the Rocky Mountains, northern Great Plains, and Great Lakes region.
Habitat: Open forests and open areas, from low to high elevations in the mountains.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
• var. dasycephala – pale goat-chicory
• var. glauca – pale agoseris, short beaked agoseris
Agoseris grandiflora – large-flowered agoseris
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Montana, Idaho and Nevada.
Habitat: Prairies, balds, meadows, and forest openings, often where seasonally dry, from low to middle elevations in the mountains.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
• var. grandiflora – large flowered agoseris, large flower goat-chicory
• var. leptophylla – Puget Sound agoseris
Agoseris heterophylla – annual agoseris
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east to Idaho, Montana, Utah, and Arizona.
Habitat: Dry, open areas at low to mid-elevations.
Origin: Native
Flowers: April-July
Growth Duration: Annual
• var. heterophylla
Agoseris monticola – mountain agoseris, Sierra Nevada agoseris
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to Nevada.
Habitat: Mesic meadows in the subalpine and alpine, often in soils of volcanic origin.
Origin: Native
Flowers: July-August
Growth Duration: Perennial
Agoseris retrorsa – spear leaved agoseris, spear leaf goat-chicory
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to Nevada, Utah, and Arizona.
Habitat: Sagebrush desert, grassy slopes, and ponderosa pine forest openings at low to middle elevations.
Origin: Native
Flowers: May-June
Growth Duration: Perennial
Agrimonia gryposepala – tall hairy agrimony, tall hairy grooveburr
Distribution: Reported from Washington but currently no specimens exist; British Columbia to California, east to the Rocky Mountains.
Habitat: Edges, openings, draws, thickets, and open forest.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Agropyron cristatum – crested wheatgrass
Distribution: Occurring east of the Cascades crest in Washington; Alaska to California, east across much of North America to the Atlantic Coast.
Habitat: Dry, open areas where distiurbed; frequently planted for soil stabilization and forage.
Origin: Introduced from Eurasia
Flowers: June-August
Growth Duration: Perennial
Agropyron fragile – Siberian wheatgrass
Distribution: Occurring east of the Cascades crest in Washington; south-central British Columbia to southeastern Idaho.
Habitat: Sagebrush desert, roadsides, wastelots, and other disturbed areas.
Origin: Introduced from Eurasia
Flowers: May-July
Growth Duration: Annual
Agrostemma githago – common corncockle
Distribution: Occurring in scattered locations on both sides of the Cascades crest in Washington; Alaska to California, east across most of North America to the Atlantic Coast.
Habitat: Roadsides and wasteland.
Origin: Introduced from Europe
Flowers: June-July
Growth Duration: Annual
• var. githago – common corncockle
Agrostis capillaris – colonial bentgrass
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across most of North America to the Atlantic Coast.
Habitat: Open, disturbed areas often at low elevations.
Origin: Introduced from Europe
Flowers: June-August
Growth Duration: Perennial
Agrostis castellana – Highland bentgrass, dryland browntop
Distribution: Occurring west of the Cascades crest in lowland western Washington: southwestern British Columbia to California.
Habitat: Disturbed sites, roadsides, and gravel bars.
Origin: Introduced from Europe
Flowers: May-July
Growth Duration: Perennial
Agrostis densiflora – California bentgrass
Distribution: Occurring west of the Cascades crest in western Washington along the outer coast; coastal Washington to California.
Habitat: Coastal bluffs.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Agrostis exarata – spiked bentgrass
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to Alberta, Nebraska and Texas.
Habitat: Moist areas, from near sea level to mid-elevations in the mountains.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
Agrostis gigantea – black bentgrass
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Atlantic Coast.
Habitat: Disturbed sites, roadsides, edge of agricultural fields, mostly at low elevations.
Origin: Introduced from Eurasia
Flowers: June-September
Growth Duration: Perennial
Agrostis idahoensis – Idaho bentgrass
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Subalpine and alpine meadows, along wet seepage areas, bogs, and wet openings in coniferous forests.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Agrostis mertensii – Merten's bentgrass, northern bentgrass
Distribution: Occurring in the Cascades Range in Washington; Alaska to northern Washington; circumboreal.
Habitat: Rocky alpine meadows and ridgelines.
Origin: Native
Flowers: July-August
Growth Duration: Perennial
Agrostis microphylla – small-leaf bentgrass
Distribution: Occurring west of the Cascades crest and in the Columbia River Gorge in Washington; southwestern British Columbia to California.
Habitat: Seasonally wet areas on thin, rocky or sandy substrates, vernal pools, cliffs, and serpentine areas.
Origin: Native
Flowers: May-June
Growth Duration: Annual
Agrostis oregonensis – Oregon bentgrass
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Montana, Wyoming, and Nevada.
Habitat: Stream and lake margins, damp woodlands and meadows.
Origin: Native
Flowers: July-August
Growth Duration: Perennial
Agrostis pallens – seashore bentgrass
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia to California, east to western Montana and Utah.
Habitat: Coastal sands and cliffs, meadows, open, dry lowlands to subalpine forest.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Agrostis scabra – rough bentgrass
Distribution: Widely distributed on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Disturbed sites in grassl, open forest, marshes, and lakesides, often along roads and ditches.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Agrostis stolonifera – spreading bentgrass
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Wet, disturbed areas that include streambanks, flooded fields, and ditches at low to moderate elevations.
Origin: Introduced from Eurasia
Flowers: June-September
Growth Duration: Perennial
Agrostis variabilis – alpine bentgrass
Distribution: Occurring on both sides of the Cascades crest in Washington British Columbia to California, east to the Rocky Mountains.
Habitat: Wet subalpine and alpine seeps and meadows.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
Ailanthus altissima – tree-of-heaven
Distribution: Occurring chiefly east of the Cascades crest in Washington, British Columbia to California, east across most of North America to the Atlantic Coast.
Habitat: Escaped ornamental in roadsides, waste areas, along railroad tracks, and other open, disturbed areas.
Origin: Introduced from China
Flowers: May-July
Growth Duration: Perennial
Aira caryophyllea – silver hairgrass
Distribution: Occurring west of the Cascades crest in Washington and east in the Columbia River Gorge; British Columbia to California, east to Idaho and Wyoming, also in the southeastern U.S. and northeastern North America.
Habitat: Balds, prairies, meadows, forest openings, roadsides, wastelots, and other open areas at low to middle elevations.
Origin: Introduced Eurasia and North Africa
Flowers: May-August
Growth Duration: Annual
• var. caryophyllea – silver hairgrass
Aira praecox – early silver hairgrass
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia to California; also in eastern North America.
Habitat: Gravelly prairies, sea bluffs and dunes near the coast, also in other disturbed, open areas at low elevations.
Origin: Introduced from Europe
Flowers: April-September
Growth Duration: Annual
Ajuga reptans – carpet bugle
Distribution: Occurring west of the Cascades crest in Washington; British Columbia to Oregon, east in scattered locations in Idaho and Montana; widespread in central and eastern North America.
Habitat: Disturbed ground, often in forest understory.
Origin: Introduced from Europe
Flowers: April-June
Growth Duration: Perennial
Alhagi maurorum – camelthorn
Distribution: Occurring east of the Cascades crest in Washington; Washington, Idaho, and California east to Colorado and Texas.
Habitat: Disturbed areas in arid lands at low to moderate elevations.
Origin: Introduced from Asia
Flowers: June-August
Growth Duration: Perennial
Aliciella leptomeria – Great Basin gilia, sand gily-flower
Distribution: Occurring east of the Cascades crest in Washington; Washington south to California, east to the Rocky Mountains.
Habitat: Open, sandy and rocky areas in sagebrush steppe from low to middle elevations.
Origin: Native
Flowers: April-June
Growth Duration: Annual
Aliciella lottiae – Lott's gily-flower
Distribution: Occurring east of the Cascades crest in the south-central portion of Washington; Washington south to California, east to Idaho and Utah.
Habitat: Open, sandy areas in sagebrush-steppe at low to middle elevations.
Origin: Native
Flowers: April-June
Growth Duration: Annual
Alisma gramineum – grass-leaved water-plantain, narrow-leaf water-plantain
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east to Minnesota and Wisconsin.
Habitat: Marshy areas, often in standing water.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Alisma plantago-aquatica – European water plantain
Distribution: Currently only known from King County in Washington; Alaska, where native, to British Columbia, where also introduced.
Habitat: Marshy areas, sometimes largely submerged.
Origin: Introduced from Eurasia and Alaska
Flowers: June-September
Growth Duration: Perennial
Alisma triviale – northern water plantain
Distribution: Widely distributed on both sides of the Cascades crest in Washington; Alaska to California, east across much of North America to the Atlantic Coast.
Habitat: Streams, lakes, ponds, wet ditches, wetlands, and cattle ponds.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
Alliaria petiolata – garlic mustard
Distribution: Occurring west of the Cascades crest in lowland western Washington; British Columbia to Oregon, also in Utah, widespread from central Great Plains to eastern North America.
Habitat: Disturbed forest understory, often where moist, at low elevations.
Origin: Introduced from Europe
Flowers: April-June
Growth Duration: Annual, Biennial
Allium acuminatum – taper-tip onion
Distribution: Widely distributed on both sides of the Cascades crest in Washington; British Columbia to California, east to Wyoming.
Habitat: Balds, grasslands, rocky outcroppings, dry slopes, and other open areas from low to middle elevations in the mountains.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Allium amplectens – narrow-leaf onion
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California.
Habitat: Dry slopes and open meadows at low to middle elevations.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Allium campanulatum – rosy Sierra onion
Distribution: Occurring east of the Cascades crest where known from Yakima County in Washington; Washington to California, east to Nevada.
Habitat: Dry soils at medium to high elevations.
Origin: Native
Flowers: June-July
Growth Duration: Perennial
Allium cernuum – nodding onion
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to Oregon, east to the Rocky Mountains; also in central and southeastern U.S.
Habitat: Open, somewhat moist areas, sea level to high elevations in the mountains.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Allium columbianum – Columbia onion
Distribution: Occurring east of the Cascades crest in far eastern Washington; Washington to Idaho and Montana.
Habitat: Seasonally wet soils on rock outcrops, wet meadows.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Allium constrictum – Grand Coulee onion
Distribution: Occurring east of the Cascades crest in Grant and Douglas counties in Washington.
Habitat: Shallow, vernally-moist soils in low, open areas.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Allium crenulatum – scalloped onion
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to Oregon.
Habitat: Forest openings and mountain meadows, moderate to high elevations.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Allium dictuon – Blue Mountain onion
Distribution: Occurring east of the Cascades crest in Washington, where endemic to Columbia County.
Habitat: Open, fairly dry, rocky areas at low to middle elevations.
Origin: Native
Flowers: June-July
Growth Duration: Perennial
Allium douglasii – Douglas' onion
Distribution: Occurring east of the Cascades crest in Washington; central and eastern Washington to northeastern Oregon.
Habitat: Open, vernally-moist areas at low to moderate elevations.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Allium fibrillum – Cuddy Mountain onion, fringed onion
Distribution: Occurring chiefly in the southeastern counties of Washington; Washington east to Montana, south to Oregon.
Habitat: Moist, shallow soils in the mountains.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Allium geyeri – Geyer's onion
Distribution: Occurring east of the Cascades crest in Washington; southern Vancouver Island to Arizona, east to the Rocky Mountains and northern Great Plains.
Habitat: Low meadows and along streams.
Origin: Native
Flowers: May-June
Growth Duration: Perennial
• var. geyeri – Geyer's onion
• var. tenerum – Rydberg's onion
Allium macrum – rock onion
Distribution: Occurring east of the Cascades crest in Washington; central Washington to southern Oregon and southwestern Idaho.
Habitat: Lithosol and barren, gravelly soils in the shrub-steppe.
Origin: Native
Flowers: April-May
Growth Duration: Perennial
Allium nevii – Nevius's garlic, Nevius's onion
Distribution: Occurring east of the Cascades crest in central Washington; Chelan County, Washington to Wasco County, Oregon
Habitat: Vernally wet meadows and rocky soils at low to middle elevations.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Allium robinsonii – Robinson's onion
Distribution: Near the Columbia River in Washington; Washington south to north-central Oregon.
Habitat: Sand and gravel near the river to rocky, even lithosol benches.
Origin: Native
Flowers: April-May
Growth Duration: Perennial
Allium sativum var. sativum – garlic
Origin: Introduced from Old World, exact origin unknown
Allium schoenoprasum – chives
Distribution: Occurring east of the Cascades crest in Washington; Alaska to Oregon and Nevada, east to the Rocky Mountains, further east across Canada to the Great Lakes region and eastern North America.
Habitat: Wet meadows, rocky or gravelly streambanks and lake shores
Origin: Both native and introduced populations
Flowers: April - August
Growth Duration: Perennial
Allium scilloides – fragile onion, scilla-like onion
Distribution: Occurring east of the Cascades crest, where endemic in Washington from Douglas to Klickitat counties.
Habitat: Scablands and dry, barren, gravelly soils.
Origin: Native
Flowers: March-April
Growth Duration: Perennial
Allium textile – textile onion, white wild onion
Distribution: Reported to occur east of the Cascades crest in southeastern Washington, but no specimens have been seen; Alberta to northeastern Nevada, east to Utah and New Mexico.
Habitat: Open areas in plains and low hills.
Origin: Native
Flowers: May-June
Growth Duration: Perennial
Allium tolmiei – Tolmie's onion
Distribution: Occurring east of the Cascades crest in southeastern Washington; southeastern Washington to adjacent western to Idaho, south to northeastern California.
Habitat: Rocky, gravelly or clayey soils, generally with sparse cover.
Origin: Native
Flowers: April-July
Growth Duration: Perennial
• var. tolmiei – Tolmie's onion
Allium validum – Pacific onion, swamp onion
Distribution: Occurring near Mount Rainier in Washington, where likely introduced; southern British Columbia to California, east to Idaho and northern Nevada.
Origin: Introduced?
Flowers: June-August
Growth Duration: Perennial
Allium vineale – wild chives, crow garlic, wild garlic
Distribution: Occurring chiefly west of the Cascades crest in Washington; southwestern British Columbia to California; also in eastern North America.
Habitat: Disturbed areas.
Origin: Introduced from Europe
Flowers: June-August
Growth Duration: Perennial
Allotropa virgata – candystick, sugarstick
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Montana, Idaho, and Nevada.
Habitat: Deep humus of coniferous forests at low to middle elevations.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
Alnus glutinosa – Black alder, European alder
Distribution: Occurring west of the Cascades crest in King County, where escaping from a wetland restoration planting. Great Lakes region east to the Atlantic Coast.
Habitat: Wetlands at low elevation.
Origin: Introduced from Europe
Flowers: March-May
Growth Duration: Perennial
Alnus incana – mountain alder
Distribution: Occurring chiefly east of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains, northern Great Plains, and eastern North America,
Habitat: Moist places, streamsides, and avalanche chutes from low to middle elevations.
Origin: Native
Flowers: March-May
Growth Duration: Perennial
• ssp. tenuifolia – mountain alder
Alnus rhombifolia – white alder
Distribution: Chiefly east of the Cascades crest in Washington; Washington to California and Nevada, east to Idaho.
Habitat: Near streams at low elevations.
Origin: Native
Flowers: January-April
Growth Duration: Perennial
Alnus rubra – red alder
Distribution: Occurring chiefly west of the Cascades crest in Washington; Alaska to California, disjunct to the east in northern Idaho.
Habitat: Moist areas at low elevations.
Origin: Native
Flowers: March-April
Growth Duration: Perennial
Alnus viridis – green alder, mountain alder
Distribution: Widely distributed throughout the mountainous areas on both sides of the Cascades crest in Washington; Alaska to California, east across the northern half of North America to the Atlantic Coast.
Habitat: Moist areas, low to high elevations.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
• ssp. fruticosa – Siberian alder
• ssp. sinuata – mountain alder, Sitka alder
Alopecurus aequalis – little foxtail, short-awn foxtail
Distribution: Widely distributed on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Shores, riverbanks, vernal pools, sloughs, wet meadows, and seeps, often submersed.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
• var. aequalis
Alopecurus arundinaceus – creeping meadow-foxtail
Distribution: Occurring east of the Cascades crest in Washington; central British Columbia to Washington, east to the Rocky Mountains and northern Great Plains; also in scattered locations in eastern North America.
Habitat: Alkaline meadows and shores, ditches, shores.
Origin: Introduced from Eurasia
Flowers: May-July
Growth Duration: Perennial
Alopecurus carolinianus – tufted meadow-foxtail
Distribution: Occurring on both sides of the Cascades crest in Washington; southern British Columbia to California, east to the Atlantic Coast.
Habitat: Shores, wet meadows, vernal pools, ditches.
Origin: Introduced from central North America?
Flowers: May-July
Growth Duration: Annual
Alopecurus geniculatus – water foxtail
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Atlantic Coast in Canada.
Habitat: Wet places, often in standing water.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Alopecurus myosuroides – slender meadow-foxtail
Distribution: Occurring chiefly east of the Cascades crest in Washington; southwestern British Columbia to California, also in the southern and eastern U.S. and Canadian Great Plains.
Habitat: Margins of cultivated fields, damp roadsides, and vernal pools.
Origin: Introduced from Eurasia
Flowers: June-August
Growth Duration: Annual
Alopecurus pratensis – field meadow-foxtail
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across most of North America to the Atlantic Coast.
Habitat: Swampy areas in meadows, in irrigated fields, and along roadsides.
Origin: Introduced from Europe
Flowers: June-July
Growth Duration: Perennial
Alopecurus saccatus – Pacific meadow-foxtail
Distribution: Occurring east of the Cascades crest and in the Columbia River Gorge in Washington; Washington and southwestern Oregon to California.
Habitat: Lowland vernal pools, shores, wet scabland, meadows.
Origin: Native
Flowers: May-June
Growth Duration: Annual
Alyssum alyssoides – small alyssum, pale madwort
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east across North America to the Atlantic Coast.
Habitat: Meadows, forest openings, sagebrush flats, roadsides, fields, and disturbed open areas at low to middle elevations.
Origin: Introduced from Eurasia
Flowers: May-July
Growth Duration: Annual, Biennial
Alyssum desertorum – desert alyssum
Distribution: East of the Cascades in Washington; widely distributed throughout central and western North America.
Habitat: Dry, open ground, often where disturbed.
Origin: Introduced from Eurasia
Flowers: May-June
Growth Duration: Annual
Amaranthus albus – white pigweed, tumbleweed
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east across much of North America to the Atlantic Coast.
Habitat: Dry, disturbed areas.
Origin: Introduced from tropical America
Flowers: June-September
Growth Duration: Annual
Amaranthus blitoides – matweed, prostrate pigweed
Distribution: Occurring chiefly east of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast; cosmopolitan.
Habitat: Dry, disturbed areas
Origin: Introduced from central United States
Flowers: June - September
Growth Duration: Annual
Amaranthus blitum – livid amaranth, pale amaranth
Distribution: Occurring chiefly west of the Cascades crest in Washington; southern British Columbia to California; also in the southeastern U.S. and eastern North America.
Habitat: Fields, roadsides, wastelots and other disturbed areas.
Origin: Introduced from the tropics
Flowers: May-July
Growth Duration: Annual
Amaranthus californicus – California amaranth
Distribution: Occurring east of the Cascades crest in Washington; eastern Washington to California, east to the Rocky Mountains and Great Plains.
Habitat: Moist, often alkaline flats, lakeshores, and vernal pools.
Origin: Native
Flowers: July-October
Growth Duration: Annual
Amaranthus deflexus – Argentina amaranth
Distribution: Occurring east of the Cascades crest in Washingotn, where known only from Whitman County; Washington to California; also in eastern North America.
Habitat: Open, disturbed areas.
Origin: Introduced from South America
Flowers: July-September
Growth Duration: Annual
Amaranthus hybridus – green amaranth, hybrid amaranth, smooth amaranth, green pigweed, smooth pigweed
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Atlantic Coast.
Habitat: Fields, roadsides, wastelots, and other disturbed areas.
Origin: Introduced from eastern North America
Flowers: July-October
Growth Duration: Annual
Amaranthus powellii – green amaranth, Powell's amaranth
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east across North America to the Atlantic Coast.
Habitat: Fields, roadsides, wastelots, and other disturbed areas.
Origin: Introduced from the southwestern United States and Mexico
Flowers: July-October
Growth Duration: Annual
Amaranthus retroflexus – redroot pigweed, rough pigweed
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Fields, roadsides, wastelots, and other disturbed areas.
Origin: Introduced from eastern and central North America
Flowers: July-October
Growth Duration: Annual
Amauropelta nevadensis – Nevada marsh fern, Sierra marsh fern, Sierra wood fern
Distribution: Occurring in the Cascades in Washington; Alaska to central Cascades in Washington; also in eastern Asia.
Habitat: Stream banks, moist forest, and springs, lowland to midmontane.
Origin: Native
Growth Duration: Perennial
Ambrosia acanthicarpa – flat spine bur-ragweed, annual bursage, bur ragweed
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to the Great Plains.
Habitat: Sandy soils, dunes, and other well-drained soils in open areas at low to middle elevations, often locally common.
Origin: Native
Flowers: July-October
Growth Duration: Annual
Ambrosia artemisiifolia – annual ragweed, common ragweed
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Roadsides, fields, pastures, wastelots, and other dry, disturbed, open areas at low elevations.
Origin: Introduced from eastern North America
Flowers: August-October
Growth Duration: Annual
Ambrosia chamissonis – silver beachweed, beach bur, cutleaf beach bur, silver bur-ragweed
Distribution: Occurring west of the Cascades crest along the marine coastline beaches in Washington; British Columbia, south along the coast, to California.
Habitat: Common on sandy beaches above high tide level.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
Ambrosia psilostachya – perennial ragweed, western ragweed
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east across North America to the Atlantic Coast.
Habitat: Roadsides, fields, wastelots, and other disturbed open areas.
Origin: Native
Flowers: July-October
Growth Duration: Perennial
Ambrosia trifida – giant ragweed
Distribution: Occurring chiefly east of the Cascades crest; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Roadsides, fields, wastelots, and other disturbed sites, often where moist.
Origin: Native
Flowers: July-October
Growth Duration: Annual
Amelanchier alnifolia – saskatoon, serviceberry
Distribution: Widely distributed on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains and Great Plains.
Habitat: Open woods, canyons and hillsides, sea level to subalpine.
Origin: Native
Flowers: April-July
Growth Duration: Perennial
Amelanchier utahensis – Utah serviceberry
Distribution: Occurring east of the Cascades crest in Washington; Washington to Baja California, east to the Rocky Mountains and Texas.
Habitat: Rimrock, valleys, gullies and hillsides, from sagebrush desert to mid-elevations in the mountains.
Origin: Native
Flowers: May-June
Growth Duration: Perennial
Ammannia coccinea – valley redstem
Distribution: Known only from a restoration site in King County; California east along Mexican border to central and eastern U.S.
Habitat: Restored wetland.
Origin: Introduced
Flowers: June-August
Growth Duration: Perennial
Ammannia robusta – western ammania, grand redstem
Distribution: Occurring east of the Cascades crest in Washington chiefly along the Columbia River; British Columbia to California, east to the Great Lakes region and midwestern U.S.
Habitat: Wet places, often where alkaline.
Origin: Native
Flowers: May-June
Growth Duration: Annual
Ammophila arenaria – European beachgrass
Distribution: Occurring west of the Cascades crest in Washington along the marine coast; western British Columbia to California, also in scattered locations along coast of northeastern North America.
Habitat: Sandy beaches and dunes along the coast.
Origin: Introduced from Europe
Flowers: June-August
Growth Duration: Perennial
• ssp. arenaria – European beachgrass
Ammophila breviligulata – American beachgrass
Distribution: Occurring west of the Cascades crest in Washington along the marine coast; western British Columbia to California; native from Great Lakes region east to the Atlantic Coast.
Habitat: Sandy beaches and dunes along the coast.
Origin: Introduced eastern North America
Flowers: June-August
Growth Duration: Perennial
• ssp. breviligulata – American beachgrass
Amorpha fruticosa – false indigo-bush
Distribution: Occurring chiefly east of the Cascades crest and along the Columbia River in Washington; Washington to California, east across much of North America, including eastern Canada.
Habitat: Disturbed areas, roadsides, wastelots, and often along streams, rivers and other riparian corridors.
Origin: Introduced from eastern North America, where native
Flowers: May-July
Growth Duration: Perennial
Amphiscirpus nevadensis – Nevada bulrush
Distribution: Occurring east of the Cascades crest in Washington; southern British Columbia to California, east to the Rocky Mountains (but not in Idaho) and northern Great Plains.
Habitat: Alkaline shores, limy fens, and wet meadows; rarely on dredge spoils.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Amsinckia intermedia – fireweed fiddleneck, rancher's fiddleneck
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to Baja California, Mexico, east to Idaho, Utah, Arizona, and west Texas.
Habitat: Balds, meadows, prairies, roadsides, and other open areas at low to middle elevations.
Origin: Native
Flowers: April-May
Growth Duration: Annual
Amsinckia lycopsoides – bugloss fiddleneck, tarweed fiddleneck
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east to the Great Plains, also in eastern North America.
Habitat: Roadsides, fields, meadows, grassy slopes, ponderosa pine forest openings, and other open areas from sagebrush desert into the mountains, often associated with some type of disturbance .
Origin: Native
Flowers: April-July
Growth Duration: Annual
Amsinckia menziesii – harvest fiddleneck, rigid fiddleneck, rancher's fireweed
Distribution: Occurring on both sides of the Cascades crest in Washington; Washington to California.
Habitat: Open, dry foothills.
Origin: Native
Flowers: April-July
Growth Duration: Annual
Amsinckia retrorsa – harvest fiddleneck, rigid fiddleneck
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east to Idaho and Utah.
Habitat: Relatively dry and open areas at low to moderate elevations.
Origin: Native
Flowers: April-June
Growth Duration: Annual
Amsinckia spectabilis – seaside amsinckia, seaside fiddleneck
Distribution: Occurring west of the Cascades crest in Washington; British Columbia to California.
Habitat: Coastal dunes or sandy bluffs.
Origin: Native
Flowers: May-July
Growth Duration: Annual
• var. spectabilis – seaside amsinckia, seaside fiddleneck
Amsinckia tessellata – bristly amsinckia, bristly fiddleneck, tessellate fiddleneck
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east to Idaho, south to New Mexico.
Habitat: Roadsides and dry, open slopes and flats, often in disturbed soil.
Origin: Native
Flowers: April-June
Growth Duration: Annual
• var. tessellata – bristly amsinckia, bristly fiddleneck, tessellate fiddleneck
Anaphalis margaritacea – pearly everlasting
Distribution: Widely distributed on both sides of the Cascades crest in Washington; Alaska to California, east across most of North America to the Atlantic Coast except for extreme southeastern U.S.
Habitat: Dry to somewhat moist open areas, from low elevations to the subalpine.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
Anchusa azurea – Italian alkanet, Italian bugloss
Distribution: Occurring in scattered localities on both sides of the Cascades crest in Washington; British Columbia to California, scattered localities east to the Atlantic Coast.
Habitat: Disturbed soil.
Origin: Introduced from Eurasia
Flowers: June-August
Growth Duration: Perennial
• var. azurea – Italian alkanet, Italian bugloss
Anchusa officinalis – common alkanet, common bugloss
Distribution: Occurring in scattered locations on both sides of the Cascades crest in Washington; British Columbia to California, east to Rocky Mountains and northern Great Plains, also from the Great Lakes region to northeastern North America.
Habitat: Roadsides, fields, ditches, wastelots, and other disturbed, open areas at low elevations.
Origin: Introduced from Mediterranean region
Flowers: May-July
Growth Duration: Biennial, Perennial
Andromeda polifolia – bog rosemary
Distribution: Reported to occur in northern Washington but no specimens seen; Alaska to Idaho, east across Canada, in the Great Lakes region, and in the northeastern U.S.
Habitat: Sphagnum bogs and other acidic wetlands.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
• var. polifolia – bog rosemary
Androsace filiformis – slender-stem rock-jasmine
Distribution: Occurring in the Columbia River Gorge in Washington; south-central Washington to adjacent north-central Oregon, east to Idaho, Montana, Utah and Colorado; also in northern California.
Habitat: Damp to wet meadows, shores, riparian flats and thickets.
Origin: Native
Flowers: June-July
Growth Duration: Annual
Androsace laevigata – smooth douglasia, cliff dwarf-primrose
Distribution: Occurring west of the Cascades crest in Washington; British Columbia to Oregon.
Habitat: Ledges, rocky slopes, moist talus, and ridges, lowland to alpine.
Origin: Native
Flowers: March-August
Growth Duration: Perennial
Androsace nivalis – snow douglasia
Distribution: Occurring east of the Cascades crest in Washington, where endemic to Okanogan, Chelan, Kittitas, and Douglas counties.
Habitat: Sagebrush slopes to alpine ridges and talus, often in serpentine soils.
Origin: Native
Flowers: April-August
Growth Duration: Perennial
Androsace septentrionalis – northern fairy-candelabra, rock-jasmine
Distribution: Occurring in the North Cascades in Washington; Alaska to California; east to the Rocky Mountains, northern Great Plains, and east to Newfoundland; circumpolar.
Habitat: Alpine meadows.
Origin: Native
Flowers: May-August
Growth Duration: Annual
Anemone deltoidea – threeleaf anemone, Columbian windflower
Distribution: Occurring chiefly west of the Cascades crest and east in the Columbia River Gorge in Washington; Washington to California.
Habitat: Dry to moist woodlands at low to middle elevations.
Origin: Native
Flowers: April-May
Growth Duration: Perennial
Anemone drummondii – Drummond's anemone, Drummond's windflower
Distribution: Occurring in the Olympic and Cascade Mountains in Washington; Alaska to California, east to Montana and Wyoming.
Habitat: Subalpine to alpine meadows.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
• var. drummondii – Drummond's anemone, Drummond's windflower
Anemone lyallii – little mountain anemone, Lyall's anemone, Lyall's windflower
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia to California.
Habitat: Low elevation prairies to subalpine ridges.
Origin: Native
Flowers: March-July
Growth Duration: Perennial
Anemone multifida – cliff anemone, Pacific anemone
Distribution: Occurring on both sides of the Cascades crest and in the Olympic Mountains in Washington; Alaska to California, east to the northern Great Plains, Great Lakes region, and northeastern North America.
Habitat: From forest openings in the foothills to alpine meadows.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
• var. multifida – cliff anemone, Pacific anemone, Pacific windflower
• var. saxicola – hirsute anemone, hirsute windflower
Anemone occidentalis – mountain pasqueflower, western pasqueflower
Distribution: Occurring in the Olympic and Cascade mountains in Washington; British Columbia to California, east to Alberta, Montana, Idaho, and the Wallowa Mountains of Oregon.
Habitat: Open slopes and meadows from middle elevations to the alpine.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
Anemone oregana – Oregon anemone, Oregon windflower
Distribution: Occurring in forested areas on both sides of the Cascades crest in Washington; Washington to northern California.
Habitat: Moist, open woods, low to mid-elevations in the mountains, also in marshes and bogs along the coast.
Origin: Native
Flowers: March-June
Growth Duration: Perennial
• var. felix – Oregon anemone, western wood anemone
• var. oregana – Oregon anemone, western wood anemone
Anemone parviflora – northern anemone, small-flowered anemone, northern windflower
Distribution: Occurring on both sides of the Cascades crest in the North Cascades in Washington; Alaska to northern Washington, east to Montana and Wyoming, in scattered locations in Utah and Colorado, and also east across northern Canada to the Atlantic Coast.
Habitat: Mountain meadows and subalpine stream banks.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
Anemone patens – pasqueflower, prairie-crocus
Distribution: Occurring east of the Cascades crest in the Wenatchee Mountains in Washington, where disjunct from the main species range Alaska, south in the Rocky Mountains to New Mexico, east to the northern Great Plains and the Great Lakes region, disjunct in the Wenatchee Mountains in Washington.
Habitat: Prairies to mountain slopes, mostly on well-drained soil.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
• var. multifida – cliff anemone
Anemone piperi – Piper's anemone, Piper's windflower
Distribution: Occurring east of the Cascades crest in Washington in the far eastern part of the state; Washington to northeast Oregon east to Idaho and western Montana.
Habitat: Shady woods at moderate elevations in the mountains.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Anethum graveolens – dill
Distribution: Occurring in scattered locations on both sides of the Cascades crest in Washington; British Columbia to California, east across much of North America to the Atlantic Coast.
Habitat: Roadsides, fields, wastelots, and other disturbed open areas.
Origin: Introduced from Asia
Flowers: May-August
Growth Duration: Annual
Angelica arguta – Lyall's angelica, sharp-tooth angelica
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Alberta and Utah.
Habitat: Stream banks, wet meadows, marshes and bottomlands, from the foothills and valleys to moderate elevations in the mountains.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Angelica canbyi – Canby's angelica
Distribution: Occurring chiefly east of the Cascades crest in Washington, though disjunct on the Olympic Peninsula; northern Washington to central and northeastern Oregon.
Habitat: Meadows and forest openings, generally where moist, from low to middle elevations in the mountains.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
Angelica genuflexa – kneeling angelica
Distribution: Occurring chiefly west of the Cascades crest and east in the Columbia River Gorge in Washington; Alaska to California, east in British Columbia to the Selkirk Mountains.
Habitat: Stream banks, wet meadows and other moist places, from low to middle elevations in the mountains.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
Angelica hendersonii – Henderson's angelica, woolly angelica
Distribution: Occurring on the outer coast in Washington; northwestern Washington to California.
Habitat: Coastal bluffs and sand dunes.
Origin: Native
Flowers: July-August
Growth Duration: Perennial
Angelica lucida – seacoast angelica, sea-watch
Distribution: Occurring west of the Cascades crest in Washington in the coastal counties; Alaska to California, also in eastern North America; Far East Russia.
Habitat: Coastal bluffs, beaches, and estuaries.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
Anisocarpus madioides – woodland tarplant, woodland tarweed
Distribution: Occurring west of the Cascades crest in lowland western Washington; Southern British Columbia to southern California.
Habitat: Open woods and woodland edge, and thickets.
Origin: Native
Flowers: May-July
Growth Duration: Biennial, Perennial
Antennaria alpina – alpine pussytoes
Distribution: Occurring in the North Cascades Mountains in Washington; Alaska to Washington, Montana, and Wyoming, east across Canada; circumboreal.
Habitat: Alpine meadows.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
Antennaria anaphaloides – tall pussytoes
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia, including southern Vancouver Island, to Oregon, east to Sasketchewan, Montana, Colorado, and Nevada.
Habitat: Grassy hillsides, open woodlands, and ponderosa pine forest openings from the foothills to middle elevations in the mountains.
Origin: Native
Flowers: June-July
Growth Duration: Perennial
Antennaria corymbosa – flat topped pussytoes, meadow pussytoes
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to the Rocky Mountains.
Habitat: Streamsides, willow thickets and moist meadows in subalpine and alpine areas.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Antennaria dimorpha – cushion pussytoes, low pussytoes
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and Nebraska.
Habitat: Dry, open places in sagebrush desert to ponderosa pine forest openings, often on lithosol.
Origin: Native
Flowers: April-May
Growth Duration: Perennial
Antennaria flagellaris – stoloniferous pussytoes, whip pussytoes
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to Idaho, Wyoming, South Dakota, and Nevada.
Habitat: Sagebrush desert to dry, open areas at middle elevations, often in lithosol.
Origin: Native
Flowers: April-July
Growth Duration: Perennial
Antennaria geyeri – Geyer's pussytoes, pinewoods pussytoes
Distribution: Occurring east of the Cascades crest in southern Washington; southern Washington to California, east to Nevada.
Habitat: Rocky slopes with ash, sand, or pumice soils, lithosols, and open forest.
Origin: Native
Flowers: June-July
Growth Duration: Perennial
Antennaria howellii – Howell's pussytoes
Distribution: Occurring on both sides of the Cascades crest in Washington; Yukon Territory to California, east to the Rocky Mountains, northern Great Plains, Great Lakes region, and northeastern North America.
Habitat: Rocky or sandy slopes, dry to moist grasslands, and forest openings at low to middle elevations.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
• ssp. howellii – Howell's pussytoes
• ssp. neodioica – northern pussytoes
Antennaria lanata – woolly pussytoes
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Alberta, Wyoming, and Utah.
Habitat: Dry or moist subalpine to alpine meadows, rocky slopes, and ridges.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
Antennaria luzuloides – silvery-brown pussytoes, woodrush pussytoes
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and South Dakota.
Habitat: Sagebrush grasslands at low elevations to dry, rocky slopes at middle elevations in the mountains.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
• ssp. luzuloides – silvery brown pussytoes, woodrush pussytoes
Antennaria media – alpine pussytoes, Rocky Mountain pussytoes
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains; circumboreal
Habitat: On rocky slopes and ridges, and in talus and pumice, from subalpine to alpine meadows.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
Antennaria microphylla – little-leaf pussytoes, rosy pussytoes, white pussytoes
Distribution: Occurring on both sides of the Cascades crest in Washington, but more common east of the crest; Alaska to California, east to the Rocky Mountains and northern Great Plains, Great Lakes region, and eastern Canada.
Habitat: Dry to moist habitats, including meadows, ponderosa pine forest openings, rocky slopes, and floodplains from the lowlands to the alpine.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Antennaria monocephala – pygmy pussytoes, single-headed pussytoes
Distribution: Reported from the North Cascades in Washington; Alaska to British Columbia, east to Alberta, Montana, and Wyoming; also in the Russian Far East.
Habitat: Alpine meadows, ridges, and rocky outcroppings.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
Antennaria parvifolia – little-leaf pussytoes, Nuttall's pussytoes
Distribution: Occurring east of the Cascades crest in northeastern Washington; British Columbia to Oregon, east to the Rocky Mountains, Great Plains, and Great Lakes region.
Habitat: Meadows, open forest, gravelly slopes, and sandy flats from the lowlands middle elevations in the mountains.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Antennaria pulcherrima – showy pussytoes
Distribution: Occurring east of the Cascades crest in Washington; Alaska to Washington, east to the Rocky Mountains, east across Canada to the Atlantic Coast.
Habitat: Streams, wet thickets and meadows, and peatlands from middle elevations to the alpine.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
Antennaria pulvinata – white pussytoes
Distribution: Occurring on both sides of the Cascades crest in Washington, but more common east of the crest; Yukon Territory to northern Washington, east to Alberta and Montana.
Habitat: Alpine areas where rocky.
Origin: Native
Flowers: July-August
Growth Duration: Perennial
Antennaria racemosa – Hooker's pussytoes, raceme pussytoes
Distribution: Widely distributed in mountainous areas on both sides of the Cascades crest in Washington; British Columbia to California, east to Alberta, Montana, and Wyoming.
Habitat: Dry to damp rocky slopes, forest openings, and ledges from low to elevations to the alpine.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
Antennaria stenophylla – narrowleaved pussytoes
Distribution: Occurring east of the Cascades crest in Washington; Washington to Nevada, east to central Idaho.
Habitat: Rocky slopes, flats, lithosol areas, and dry grasslands in sagebrush desert.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Antennaria umbrinella – brown-bract pussytoes, umber pussytoes
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east to Saskatchewan, Montana, Wyoming, and Colorado.
Habitat: Forest openings at middle elevations to subalpine meadows.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
Anthemis arvensis – corn chamomile, field chamomile
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia to California, east to the northern Great Plains in the U.S, widespread from the midwestern U.S. to eastern North America.
Habitat: Roadsides, fields, wastelots, and other disturbed open areas generally at low elevations.
Origin: Introduced from Europe
Flowers: June-August
Growth Duration: Annual
Anthemis cotula – mayweed chamomile, stinking chamomile, dogfennel
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Roadsides, fields, ditches, wastelots, and other disturbed areas generally at low elevations.
Origin: Introduced from Europe
Flowers: May-October
Growth Duration: Annual
Anthoxanthum aristatum – annual vernalgrass
Distribution: Occurring in scattered locations on both sides of the Cascades crest in Washington; British Columbia to California; occurring throughout most of central and eastern half of North America.
Habitat: Meadows, grasslands, forest openings, and other disturbed, open areas at low to moderate elevations.
Origin: Introduced from Europe
Flowers: May-July
Growth Duration: Annual
• ssp. aristatum – small sweet vernal grass
Anthoxanthum odoratum – sweet vernalgrass
Distribution: Occurring chiefly west of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains, southern Great Plains, and eastern North America.
Habitat: Roadsides, fields, meadows, prairies, balds, lawns, and other disturbed open areas at low elevations.
Origin: Introduced from Europe
Flowers: April-July
Growth Duration: Perennial
Anthriscus caucalis – burr chervil
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east across much of the United States and parts of Canada to the Atlantic Coast.
Habitat: Roadsides, forest edges, wastelots, and other disturbed areas where often seasonally moist.
Origin: Introduced from Eurasia
Flowers: April-July
Growth Duration: Annual
Anthriscus sylvestris – wild chervil
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to Oregon, east to Idaho, also in eastern North America and Greenland.
Habitat: Roadsides, fields, forest edge, wastelots, and other disturbed areas where seasonally moist.
Origin: Introduced from Eurasia
Flowers: May-August
Growth Duration: Annual
Anticlea elegans – glaucous death camas
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to Oregon and Nevada, east across much of North America to the Atlantic Coast.
Habitat: Meadow, open forests and rocky slopes, mid- to high elevations in the mountains.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Anticlea occidentalis – bronze bells, mission bells, western featherbells
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Alberta, Idaho, and Montana.
Habitat: Wet cliffs, moist meadows and scree, mostly at middle to high elevations, but down to near sea level in the Olympic Peninsula and the Columbia River Gorge.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Antirrhinum majus – garden snapdragon, greater snapdragon
Distribution: Occasionally escaped from cultivation in western Washington.
Habitat: Disturbed areas in urban settings.
Origin: Introduced from Europe
Flowers: May-July
Growth Duration: Annual
Apera interrupta – dense silky-bent
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains; also in the central U.S., Great Lakes region, and northeastern U.S.
Habitat: Dry wasteland and other disturbed areas in shrub-steppe and open coniferous forests.
Origin: Introduced from Europe
Flowers: May-July
Growth Duration: Annual
Aphanes arvensis – western lady's-mantle, field parsley-piert
Distribution: Occurring west of the Cascades crest and in the Columbia River Gorge in Washington; southern British Columbia to California, reported in Idaho, also along Atlantic Coast in the U.S.
Habitat: Ledges, often limy, sandy shores, hot springs, and other disturbed open ground at low elevations.
Origin: Introduced from Eurasia and northern Africa
Flowers: April-May
Growth Duration: Annual
Aphanes australis – small-fruited parsley-piert
Distribution: Occurring west of the Cascades crest in Washington; southwestern British Columbia to northwestern Oregon, also in southeastern U.S.
Habitat: Openings, shores, lawns, and other disturbed areas at low elevations.
Origin: Introduced from Europe
Flowers: March-May
Growth Duration: Perennial
Aphanes occidentalis – western parsley-piert
Distribution: Occurring west of the Cascades crest in lowland western Washington and east in the Columbia River Gorge; southern British Columbia to California.
Habitat: Vernally damp grasslands, balds, fields, ledges, rocky slopes, open forest, shores, and beaches at low elevations.
Origin: Native
Flowers: April-June
Growth Duration: Annual
Aphyllon californicum – California broomrape
Distribution: Occurring west of the Cascades crest and east in the Columbia River Gorge in Washington; southwestern British Columbia to Baja California, also east of the Cascades crest in Oregon.
Habitat: Coastal and sub-coastal, or in meadows inland, parasitic on Asteraceae but not on Artemisia tridentata.
Origin: Native
Flowers: April-June
Growth Duration: Annual, Perennial
• ssp. californicum – California broomrape
• ssp. grayanum – Gray's California broomrape
Aphyllon corymbosum – flat-topped broomrape
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and the Canadian Great Plains.
Habitat: Sagebrush desert areas, parasitic mainly on Artemisia tridentata.
Origin: Native
Flowers: May-July
Growth Duration: Annual, Perennial
• ssp. corymbosum – flat-topped broomrape
• ssp. mutabile – flat-topped broomrape
Aphyllon fasciculatum – clustered broomrape
Distribution: Occurring east of the Cascades crest in Washington; Alaska to California, east to the Great Plains and the Great Lakes region.
Habitat: Dry, open places, valleys to montane, parasitic exclusively on Artemisia.
Origin: Native
Flowers: May-July
Growth Duration: Annual
Aphyllon franciscanum – clustered broomrape
Distribution: Occurring on both sides of the Cascades crest in Washington; southwestern British Columbia to Baja California, east to the Rocky Mountains and Texas.
Habitat: Open areas from low to middle elevations. Parasitic on Eriogonum, Eriophyllum lanatum, and Phacelia, also other taxa outside of Washington, but never Artemisia.
Origin: Native
Flowers: April-August
Growth Duration: Perennial
Aphyllon ludovicianum – Louisiana broomrape, Suksdorf's broomrape
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to Oregon, east to the Rocky Mountains and Great Plains of Canada and the U.S.
Habitat: Dry, open, often sandy areas, parasitic on Artemisia, Chrysopsis, and other woody Asteraceae.
Origin: Native
Flowers: May-July
Growth Duration: Annual
Aphyllon pinorum – pine broomrape, pinewoods broomrape
Distribution: Occurring on both sides of the Cascades crest in Washington; Washington to California, east to northern Idaho, Nevada and New Mexico.
Habitat: Montane coniferous forest, parasitic on Holodiscus.
Origin: Native
Flowers: June-August
Growth Duration: Annual
Aphyllon purpureum
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to Alberta and the Rocky Mountains.
Habitat: From lowland to montane, often where open and seasonally moist, parasitic mainly on Asteraceae, Saxifragaceae, and Sedum.
Origin: Native
Flowers: April-August
Growth Duration: Annual
Apium graveolens – celery
Distribution: Occurring in scattered locations on both sides of the Cascades crest in Washington; Washington to California, east to Idaho, Utah, and Nevada, east across the southern U.S. to eastern North America.
Habitat: Disturbed ground, usually where moist, where escaped from nearby cultivation.
Origin: Introduced from Europe
Flowers: June-August
Growth Duration: Perennial
• var. dulce
Apocynum androsaemifolium – flytrap dogbane, spreading dogbane
Distribution: Occurring on both sides of the Cascades crest in Washington, but more common east of the crest; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Common in forest openings, thickets, hillsides, roadsides, meadows and other open areas with dry soil, from low elevations to nearly subalpine areas.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
Apocynum cannabinum – clasping-leaved dogbane, common dogbane, hemp dogbane
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east across North America to the Atlantic Coast.
Habitat: Stream banks, moist hillsides and forest openings, fields, and wastelots at low to middle elevations.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
Apocynum ×floribundum – western dogbane
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east across North America to the Atlantic Coast.
Habitat: Dry, open areas, gen in valleys and at lower elevations in the mountains.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
Aquilegia flavescens – yellow columbine
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to Oregon, east to the Rocky Mountains.
Habitat: Moist mountain meadows and talus to alpine slopes
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Aquilegia flavescens × Aquilegia formosa var. formosa
Origin: Native
Aquilegia formosa – red columbine, Sitka columbine
Distribution: Widely distributed on both sides of the Cascades crest throughout Washington; Alaska to California, coastal and inland to Alberta and Wyoming.
Habitat: Open woods, from the lowlands to moderate elevations in the mountains.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
• var. formosa – red columbine, Sitka columbine, western columbine
Aquilegia vulgaris – European Columbine
Distribution: Introduced as a garden flower, occasionally escaping.
Habitat: Disturbed soil near gardens.
Origin: Introduced
Flowers: May-July
Growth Duration: Perennial
Arabidopsis kamchatica – kamchatka rockcress, lyre-leaved rockcress, western rockcress
Distribution: Occurring west of the Cascades crest in northwestern Washington; Alaska to Washington, east to Northwest Territory and Sasketchewan.
Habitat: Subalpine and alpine scree and talus slopes.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
Arabidopsis thaliana – mouse-ear cress, thalecress
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east across most of North America.
Habitat: Disturbed areas, particularly near cities and towns.
Origin: Introduced from Eurasia
Flowers: March-May
Growth Duration: Annual
Arabis caucasica – mountain rockcress
Distribution: Known only from San Juan County in Washington; Yukon Territory to northwestern Washington.
Habitat: Open, disturbed areas at low elevation, often near where cultivated.
Origin: Introduced
Flowers: May-June
Growth Duration: Perennial
Arabis crucisetosa – crosshaired rockcress
Distribution: Occurring in the southeastern corner of Washington; Snake River canyon, Asotin County, Washington, east to west-central Idaho.
Habitat: Wet banks to moist soil or coniferous woods.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Arabis eschscholtziana – hairy rockcress, Pacific coast rockcress
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the northern Rocky Mountains.
Habitat: Open areas, often in waste places, from sea level to mid-elevations in the mountains.
Origin: Native
Flowers: April-July
Growth Duration: Annual, Biennial, Perennial
Arabis furcata – Cascade rockcress, Columbia Gorge rockcress, fork-haired rockcress
Distribution: Occurring on both sides of the Cascades crest in Washington; Washington to Oregon.
Habitat: Open slopes, meadows, and ridgelines in alpine and subalpine areas, and exposed areas in the Columbia River Gorge.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Arabis nuttallii – Nuttall's rockcress
Distribution: Occurring east of the Cascades crest in Washington; eastern British Columbia to eastern Washington, east to Alberta, Montana, Wyoming, and Utah.
Habitat: Moist flats, often sheltered by shrubs, from the foothills to middle elevations in the mountains.
Origin: Native
Flowers: April-August
Growth Duration: Perennial
Arabis olympica – Olympics rockcress
Distribution: Occurring west of the Cascades crest in Washington, where endemic to the Olympic Mountains.
Habitat: Talus slopes and subalpine meadows.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Aralia nudicaulis – wild sarsaparilla
Distribution: Occurring east of the Cascades crest in northeastern Washington; Yukon Territory to northeastern Washington, east to and south in Rocky Mountains, east to eastern North America.
Habitat: Moist, shaded soil.
Origin: Native
Flowers: May-June
Growth Duration: Perennial
Arbutus menziesii – Pacific madrona, Pacific madrone
Distribution: Occurring west of the Cascades crest and in the Columbia River Gorge in Washington; British Columbia to California.
Habitat: Chiefly in drier, often rocky areas at low elevations.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Arbutus unedo – strawberry tree
Distribution: Occurring west of the Cascades crest in Washington; currently known as escaped from cultivation in Washington.
Habitat: Disturbed, open to partially sunny areas in and around urban areas, where escaped from cultivation.
Origin: Introduced
Flowers: April-September
Growth Duration: Perennial
Arceuthobium abietinum
Origin: Native
Arceuthobium americanum – lodgepole pine dwarf-mistletoe
Distribution: Chiefly east of the Cascades crest in Washington; southern British Columbia south to California, east to Montana, Colorado and New Mexico.
Habitat: Parasitic on Pinus, usually on Pinus contorta.
Origin: Native
Flowers: April- June
Growth Duration: Perennial
Arceuthobium campylopodum – western dwarf-mistletoe
Distribution: In the Pacific Northwest on Pinus contorta and P. ponderosa (Compare range of these two species)
Habitat: Parasitic on Pinus contorta and P. ponderosa, sea level to mid-elevations in the mountains
Origin: Native
Flowers: Late June - September
Growth Duration: Perennial
Arceuthobium douglasii – Douglas-fir dwarf-mistletoe
Distribution: British Columbia to California, east to Montana and New Mexico.
Habitat: On the branches of Pseudotsuga menziesii.
Origin: Native
Flowers: May - June
Growth Duration: Perennial
Arceuthobium laricis – larch dwarf-mistletoe
Origin: Native
Growth Duration: Perennial
Arceuthobium tsugense – hemlock dwarf mistletoe
Origin: Native
Growth Duration: Perennial
• ssp. contortae
• ssp. tsugense – hemlock mistletoe
Arcteranthis cooleyae – Cooley's buttercup
Distribution: Occurring west of the Cascades crest in Washington; Alaska to Washington.
Habitat: Damp slopes and rocky crevices at high elevations, blossoming as snow recedes.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Arctium lappa – great burdock, greater burdock
Distribution: Known from a few scattered locations in Washington; British Columbia to California, in Montana, east from California to Colorado and Arizona, also across Canadian Great Plains to Great Lakes region and northeastern North America.
Habitat: Roadsides, ditches, forest openings and edge, wastelots, and other disturbed areas generally at low elevations.
Origin: Introduced from Eurasia
Flowers: August-October
Growth Duration: Biennial, Perennial
Arctium minus – common burdock, lesser burdock
Distribution: Occurring on both sides of the Cascades crest in Washington; British to California, east across North America to the Atlantic Coast.
Habitat: Roadsides, fields, meadows, wastelots, and other disturbed open areas at low to middle elevations.
Origin: Introduced
Flowers: July-October
Growth Duration: Biennial
Arctostaphylos columbiana – bristly manzanita
Distribution: Occurring west of the Cascades crest and in the Columbia River Gorge in Washington; British Columbia to California.
Habitat: Dry forest openings and rocky slopes, mostly at low elevations.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Arctostaphylos ×media – medium manzanita
Distribution: Occurring west of the Cascades crest in Washington, chiefly on the east side of the Olympic Peninsula. Washington to Oregon.
Habitat: Rocky balds and forest openings from low to moderate elevations.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Arctostaphylos nevadensis – pinemat manzanita
Distribution: Occurring on both sides of the Cascades crest in Washington; Washington to California, east to Nevada.
Habitat: Dry forest edge and openings from middle elevations in the mountains to the subalpine.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
• ssp. nevadensis – pinemat manzanita
Arctostaphylos nevadensis × Arctostaphylos patula
Origin: Native
Arctostaphylos patula – green-leaf manzanita
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to Montana and Colorado.
Habitat: Low elevations in the mountains.
Origin: Native
Flowers: May-June
Growth Duration: Perennial
Arctostaphylos uva-ursi – red bearberry, kinnikinnick
Distribution: Widely distributed on both sides of the Cascades crest in Washington; Alaska to California east to the Rocky Mountains, also further east across the northern U.S. and Canada to the Atlantic Coast; circumboreal.
Habitat: Coastal bluffs and prairies, rocky balds, dry subalpine meadows, and dry coniferous forest openings.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Arenaria paludicola – marsh sandwort
Distribution: Presumed extirpated from Washington; historically west of the Cascades crest along the coast. California to Central America.
Habitat: Swampy places, mostly along coast.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
Arenaria serpyllifolia – thyme-leaf sandwort
Distribution: Widely distributed on both sides of the Cascades crest in Washington; British Columbia to California, east across North America to the Atlantic Coast.
Habitat: Dry to moist, barren to wooded places.
Origin: Introduced from Europe
Flowers: May-July
Growth Duration: Annual
• var. serpyllifolia – thyme-leaf sandwort
Aristida purpurea – threeawn
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to central Canada and the central U.S.
Habitat: Desert plains, grasslands, and pondersoa pine forests.
Origin: Native
Flowers: June-July
Growth Duration: Annual, Perennial
• var. longiseta – red threeawn
Armeria arenaria – Jersey thrift
Distribution: Occurring west of the Cascades crest in Washington; not known from elsewhere in North America.
Habitat: Roadsides, fields, ditches, and other disturbed open areas at low elevations.
Origin: Introduced from Europe
Flowers: April-July
Growth Duration: Perennial
Armeria maritima – sea-pink, thrift
Distribution: Occurring west of the Cascades crest in Washington, chiefly in the coastal counties; Alaska to California, east across Canada to northeastern North America; Greenland and Europe.
Habitat: Along beaches, coastal bluffs and balds, occasionally inland in prairies.
Origin: Native
Flowers: March-July
Growth Duration: Perennial
• ssp. californica – sea-pink, thrift
• ssp. maritima – sea-pink, thrift
Armoracia rusticana – horseradish
Distribution: Occurring in scattered locations east of the Cascades crest in Washington; Alaska to California, east across the U.S. and Canada to the Atlantic Coast.
Habitat: Disturbed areas including fields, roadsides and wastelots.
Origin: Introduced from Eurasia
Flowers: May-July
Growth Duration: Perennial
Arnica chamissonis – leafy arnica, meadow arnica, narrowleaf arnica, silvery arnica, leafy leapordbane
Distribution: Occurring both sides of the Cascades, including the northeastern corner of Washington; Alaska to California, east to the Rocky Mountains, east across Canada to the Atlantic Coast.
Habitat: Meadows and wet places from middle elevations to the subalpine.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
Arnica cordifolia – heart-leaf arnica, heart-leaf leopardbane
Distribution: Occurring chiefly east of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains, northern Great Plains, and the Great Lakes region.
Habitat: Light forest understory, openings, and edge, from low elevations to the subalpine.
Origin: Native
Flowers: April-July
Growth Duration: Perennial
Arnica discoidea – rayless arnica, rayless leopardbane
Distribution: Occurring in the Cascades Mountains of Klickitat and Skamania counties in Washington; Washington to California, east to Nevada.
Habitat: Forest openings from middle elevations to the subalpine.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Arnica fulgens – hillside arnica, orange arnica, shining leopardbane
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and northern Great Plains.
Habitat: Meadows and open slopes from the foothills to middle elevations in the mountains
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Arnica gracilis – slender arnica, slender leopardbane
Distribution: Occurring on both sides of the Cascades crest in the mountainous areas in Washington; British Columbia to Oregon, east to Alberta, Montana, Wyoming, and Utah.
Habitat: Dry, rocky slopes and meadows, from the subalpine to alpine.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Arnica lanceolata – clasping arnica, stream bank arnica
Distribution: Occurring on both sides of the Cascades crest in Washington, including the Olympic Mountains and the northeastern region; Alaska to California, east to the Rocky Mountains, also in northeastern North America.
Habitat: Streambanks, moist woods and meadows from middle elevations to the subalpine.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
• ssp. prima – clasping arnica, streambank arnica, streambank leopardbane
Arnica latifolia – broad-leaved arnica, mountain arnica, daffodil leopardbane
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains.
Habitat: Common in forest openings and meadows, and open, rocky areas from middle to high elevations in the mountains.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Arnica longifolia – longleaf arnica, seep spring arnica, spear-leaf leopardbane
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Rocky soil in seeps or springs, cliffs, or riverbanks, from middle elevations to the alpine.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
Arnica mollis – cordilleran arnica, hairy arnica, cordilleran leopardbane
Distribution: Occurring on both sides of the Cascades crest and in the Olympic Mountains in Washington; Alaska to California, east to the Rocky Mountains.
Habitat: Moist meadows from middle elevations to the alpine.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
Arnica nevadensis – Nevada arnica, Sierra arnica, Sierran leopardbane
Distribution: Occurring in the Cascades and Olympic mountains in Washington; Washington to California, east to Nevada.
Habitat: Open, rocky slopes and forest openings in the subalpine and alpine.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Arnica ovata – sticky arnica, sticky-leaf arnica
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to Montana and Utah.
Habitat: Rocky places from middle elevations to the subalpine and alpine.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
Arnica parryi – Parry's arnica
Distribution: Occurring on both sides of the Cascades crest in Washington; Yukon Territory to California, east to the Rocky Mountains.
Habitat: Open woods and meadows, from middle elevations to the alpine.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Arnica rydbergii – Rydberg's arnica, subalpine arnica, subalpine leopardbane
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to northern California, east to Alberta and Colorado.
Habitat: Dry meadows and open slopes at high elevations in the mountains.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Arnica sororia – bunch arnica, twin arnica, twin leopardbane
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to Alberta, Montana, and Wyoming.
Habitat: From low elevation prairies and grasslands to coniferous forest openings at middle elevations.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Aronia melanocarpa – black chokeberry
Origin: Introduced
Arrhenatherum elatius – bulbous oatgrass
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across most of North America to the Atlantic Coast.
Habitat: Meadows, balds, pastures, fields, roadsides, wastelots, and other disturbed areas.
Origin: Introduced from Europe
Flowers: May-July
Growth Duration: Perennial
Artemisia absinthium – absinthe, oldman, wormwood
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east across much of North America to the Atlantic Coast.
Habitat: Roadsides, fields, ditches, wastelots, and other disturbed open areas.
Origin: Introduced from Eurasia
Flowers: July-September
Growth Duration: Perennial
Artemisia annua – sweet Annie, sweet sagewort, annual wormwood
Distribution: Occurring in scattered locations east of the Cascades crest and in the Columbia River Gorge in Washington; Washington to California, east across most of North America to the Atlantic Coast.
Habitat: Roadsides, fields, ditches, wastelots, and other disturbed open places.
Origin: Introduced from Eurasia
Flowers: August-October
Growth Duration: Annual
Artemisia arbuscula – dwarf sagebrush, low sagebrush
Distribution: Occurring east of the Cascades crest in Washington; central Washington to California, east to the Rocky Mountains.
Habitat: Open, dry plains and hills in sagebrush desert.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
• ssp. arbuscula – little sagebrush, low sagebrush
Artemisia biennis – biennial wormwood
Distribution: Occurring on both sides of the Cascades crest and in the Columbia River Gorge in Washington; Alaska to California, east across most of North America to the Atlantic Coast, where considered introduced.
Habitat: Roadsides, fields, irrigation ditches, streambanks, and other disturbed open areas, especially in sandy soil.
Origin: Native
Flowers: August-October
Growth Duration: Annual, Biennial
Artemisia campestris – Pacific sagewort, northern wormwood
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across most of North America to the Atlantic Coast; also in Eurasia.
Habitat: Open places, often in sandy or rocky soil, from low elevations to alpine.
Origin: Native
Flowers: July-September
Growth Duration: Biennial, Perennial
• var. borealis – northern wormwood
• var. scouleriana – Pacific sagewort, Scouler's wormwood
• var. wormskioldii – Columbia Islands sagewort, Wormskiold's wormwood sagewort
Artemisia cana – hoary sagebrush, silver sagebrush
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and northern Great Plains.
Habitat: Meadows and forest openings from low to middle elevations in the mountains.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
• ssp. bolanderi – Bolander's hairy sagebrush
Artemisia douglasiana – Douglas's mugwort, Douglas's sagewort, Douglas's wormwood
Distribution: Occurring on both sides of the Cascades crest and in the Columbia River Gorge in Washington; Washington to California, east to Nevada.
Habitat: Mostly along stream banks and river bottoms.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
Artemisia dracunculus – dragon sagewort, tarragon, dragon wormwood
Distribution: Occurring east of the Cascades crest in Washington; Alaska to California, east to the Great Plains and Great Lakes region.
Habitat: Sagebrush desert to ponderosa pine forest openings at middle elevations.
Origin: Native
Flowers: July-October
Growth Duration: Perennial
Artemisia frigida – prairie sagebrush, prairie sagewort
Distribution: Occurring east of the Cascades crest in Washington; Alaska to Washington, east to the Great Plains, Great Lakes region, and northeastern North America.
Habitat: Dry, open sagebrush plains and foothills.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
Artemisia furcata – three-forked mugwort, forked wormwood
Distribution: Occurring in the Cascades and Olympic Mountains of Washington; Alaska to Washington, east to Northwest Territories, Alberta, and Nunavut.
Habitat: Open, rocky ledges and talus slopes in the subalpine and alpine.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
Artemisia ludoviciana – western mugwort, prairie sage
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east across North America to the Atlantic Coast.
Habitat: Meadows and open slopes, from the lowlands to the alpine.
Origin: Native
Flowers: June-October
Growth Duration: Perennial
• ssp. candicans – gray sagewort
• ssp. incompta – intermediate sagewort, mountain wormwood
• ssp. lindleyana – Lindley's western mugwort, Lindley's prairie sage
• ssp. ludoviciana – western mugwort, Louisiana sagewort, silver wormwood
Artemisia michauxiana – Michaux's mugwort, lemon sagewort, Michaux's wormwood
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Alberta and Wyoming.
Habitat: Rocky places in the mountains at rather high elevations.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
Artemisia norvegica – mountain sagewort, boreal wormwood
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska south to California, east to the Rocky Mountains.
Habitat: Subalpine and alpine areas, typically where moist.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
• ssp. saxatilis – mountain sagewort
Artemisia rigida – scabland sagebrush, stiff sagebrush
Distribution: Occurring east of the Cascades crest in Washington; Washington to Oregon, east to Idaho and Montana.
Habitat: Dry, rocky places from the plains and foothills to moderate elevations in the mountains.
Origin: Native
Flowers: September-October
Growth Duration: Perennial
Artemisia spiciformis – snowfield sagebrush, spiked sagebrush
Distribution: Occurring east of the Cascades crest in Washington; central Washington to California, east to southwestern Montana, Wyoming, and Colorado.
Habitat: Cool, moist slopes, from middle elevations to subalpine.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
Artemisia stelleriana – dusty miller, oldwoman, beach wormwood, Steller's wormwood
Distribution: Occurring west of the Cascades crest along the northeastern coast of the Olympic Peninsula in Washington; native to Alaska, also occurring from the Great Lakes region east to northeastern North America.
Habitat: Coastal dunes and beaches in developed coastal areas, where escaping from cultivation.
Origin: Introduced
Flowers: May-September
Growth Duration: Perennial
Artemisia suksdorfii – coastal mugwort, Suksdorf's sagewort, coastal wormwood
Distribution: Occurring west of the Cascades crest in Washington; British Columbia to California.
Habitat: Bluffs, beaches, rocky areas, and riverbanks, especially near the coast.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Artemisia tilesii – Aleutian mugwort, Cascade wormwood
Distribution: Occurring in the Olympic and Cascade Mountains of Washington; Alaska to Oregon, east to Montana, and east across Canada to Quebec.
Habitat: Open rocky or gravelly, wet or dry sites, from middle elevations to the alpine, descending to sea level northward.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
Artemisia tridentata – big sagebrush
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and northern Great Plains.
Habitat: Dry plains and foothills to the subalpine, but not in lithosol or alkaline soil.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
• ssp. tridentata – big sagebrush
• ssp. vaseyana – mountain big sagebrush, Vasey sagebrush
• ssp. wyomingensis – Wyoming sagebrush
Artemisia tripartita – cut-leaf sagebrush, threetip sagebrush
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to Oregon and Nevada, east to Idaho and Wyoming.
Habitat: Sagebrush desert and grasslands.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
• ssp. tripartita – cutleaf sagebrush, threetip sagebrush
Artemisia vulgaris – mugwort, lobed wormwood
Distribution: Occurring on both sides of the Cascades crest and in the Columbia River Gorge in Washington; Alaska to Oregon, east to Montana, east across Canada to the Great Lakes region and eastern North America.
Habitat: Roadsides, fields, ditches, wastelots, and other disturbed, open areas.
Origin: Introduced from Eurasia
Flowers: August-October
Growth Duration: Perennial
Arum italicum – Italian arum, Italian lords and ladies
Distribution: Occurring west of the Cascades crest in lowland western Washington; southwestern British Columbia to California; also in scattered location in central and eastern U.S.
Habitat: Forest understory and disturbed locations near urbanized areas.
Origin: Introduced from Europe
Flowers: April-June
Growth Duration: Perennial
• ssp. italicum – Italian arum, Italian lords and ladies
Aruncus dioicus – sylvan goatsbeard
Distribution: Occurring chiefly west of the Cascades crest in Washington; Alaska to California, east to Alberta, also in the eastern half of North America.
Habitat: Moist forest and forest edge from low elevations to the subalpine.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
• var. acuminatus – Sylvan goatsbeard
Asarum caudatum – wild ginger
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Idaho and Montana.
Habitat: Moist, shady woods at low to mid-elevations in the mountains.
Origin: Native
Flowers: April-July
Growth Duration: Perennial
Asclepias cryptoceras – Humboldt milkweed, pallid milkweed
Distribution: Occurring east of the Cascades crest in southeastern Washington; southeastern Washington to California, east to Idaho, Wyoming, and Colorado.
Habitat: Gravelly to heavy clay soil in the foothills and lower mountains.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Asclepias fascicularis – Mexican whorled milkweed, narrow-leaf milkweed
Distribution: Occurring east of the Cascades crest in Washington; northeastern Washington to Baja California, Mexico, east to Idaho, Utah, and Arizona.
Habitat: Sagebrush desert, usually along vernal stream beds.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Asclepias incarnata – swamp milkweed
Distribution: Known from Okanogan County in Washington; Washington, also in Idaho, east across North America to Atlantic Coast.
Habitat: Riparian zone, including standing water
Origin: Introduced?
Flowers: August
Growth Duration: Perennial
Asclepias speciosa – showy milkweed
Distribution: Occurring east of the Cascades crest and in the Columbia River Gorge in Washington; British Columbia to Mexico, east to the Great Plains and Great Lakes region.
Habitat: Riparian corridors, irrigation ditches, roadsides, and other at least seasonally wet areas at low elevations, often in loam soils.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Askellia pygmaea – low hawksbeard
Distribution: Occurring in the Olympic and Cascades mountains in Washington; Alaska to California, east to Nunavut and Colorado, also in northeastern Canada; Asia.
Habitat: Talus, scree, moraines, sandy or gravelly slopes, subalpine to alpine.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
Asparagus officinalis – asparagus
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east to the Atlantic Coast.
Habitat: Garden escape, often of roadsides, fields, wastelots, and other disturbed areas..
Origin: Introduced from Eurasia
Flowers: June-August
Growth Duration: Perennial
Asperugo procumbens – catchweed, madwort
Distribution: Occurring east of the Cascades crest in Washington; Alaska to California, east to the Great Plains, also in eastern North America.
Habitat: Roadsides, fields, irrigation ditches, and other disturbed open areas where moist.
Origin: Introduced from Eurasia
Flowers: May-July
Growth Duration: Annual
Aspidotis densa – Oregon , Indian's dream, podfern
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Idaho, Montana, South Dakota, western Wyoming, and northern Utah; disjunct in Quebec.
Habitat: Cliff crevices and moist, rocky slopes, foothills to near timberline, often on serpentine
Origin: Native
Growth Duration: Perennial
Asplenium trichomanes – maidenhair spleenwort
Distribution: Occurring chiefly west of the Cascades crest in Washington; Alaska to California, also in southern Rocky Mountain states and in central U.S. and eastern North America.
Habitat: Cliff crevices, rocky outcroppings, and talus slopes, generally where moist.
Origin: Native
Spores: May-September
Growth Duration: Perennial
• ssp. quadrivalens – maidenhair spleenwort
• ssp. trichomanes – maidenhair spleenwort
Asplenium viride – green spleenwort
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across northern North America to New England and the Canadian Maritimes; circumboreal.
Habitat: Cliff crevices, especially on limestone, often near or above timberline.
Origin: Native
Growth Duration: Perennial
Astragalus agrestis – cock's-head, field milk vetch, purple milk vetch
Distribution: Occurring east of the Cascades crest in Washington; Yukon Territory to California, east across North America to Canada\\\'s Atlantic Coast.
Habitat: Moist spots in sagebrush plains, and mountain meadows to alpine slopes.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Astragalus alpinus – alpine milk-vetch, purple milk-vetch
Distribution: Occurring east of the Cascades crest in the north-central region of Washington; Alaska to northeastern Oregon and northeastern Nevada, east to the Rocky Mountains; circumboreal.
Habitat: Open slopes and rocky areas from upper montane to alpine.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
• var. alpinus – alpine milk-vetch
Astragalus arrectus – hanging pod milk-vetch, Palouse milk-vetch
Distribution: Occurring east of the Cascades crest in Washington, where known from Lincoln and Whitman; eastern Washington to adjacent Idaho.
Habitat: Sagebrush flats to open ponderosa pine forest.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Astragalus arthuri – Arthur's milk-vetch
Distribution: Occurring east of the Cascades crest, where known only from Asotin County in Washington; southeastern Washington to northeastern Oregon and adjacent west-central Idaho.
Habitat: Grassy hills and rocky meadows, often on basalt.
Origin: Native
Flowers: May-June
Growth Duration: Perennial
Astragalus arthurii
Origin: Native
Growth Duration: Perennial
Astragalus asotinensis – Asotin milk-vetch
Distribution: Occurring east of the Cascades crest, where known only from Asotin County in Washington; Endemic to Snake River Canyon of southeastern Washington and adjacent Idaho.
Habitat: Grassy slopes in shrub-steppe at low to moderate elevations.
Origin: Native
Flowers: March-May
Growth Duration: Perennial
Astragalus australis – Indian milk-vetch, subarctic milk-vetch
Distribution: Occurring west of the Cascades crest in the Olympic Mountains in Washington; Alaska to the Olympic mountains, northeastern Oregon, Nevada, Utah, and Colorado, east to the Great Plains and eastern Canada.
Habitat: Foothill bluffs and riverbanks to subalpine and alpine ridges and scree.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
• var. cottonii – Cotton's milk-vetch, Cotton's milkvetch
Astragalus beckwithii – Beckwith's milk-vetch
Distribution: Occurring east of the Cascades crest in the southeastern region of Washington; southeastern Washington to northeastern Nevada, east to western Idaho along the Snake River drainage, also disjunct in Kamloops, British Columbia.
Habitat: Sagebrush desert to dry hillsides.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
• var. weiserensis – Beckwith's milk-vetch
Astragalus canadensis – Canada milk-vetch
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east across North America to the Atlantic Coast.
Habitat: Prairies, stream banks, ditches, ponderosa pine forest openings, and seasonally moist alkaline flats in sagebrush.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
• var. brevidens – Canada milk-vetch
• var. canadensis – Canada milk-vetch
• var. mortonii – Morton's Canadian milk-vetch
Astragalus caricinus – buckwheat milk-vetch
Distribution: Occurring east of the Cascades crest in the south-central Washington; Washington south along the Snake River corridor to Oregon and southwestern Idaho.
Habitat: Grasslands, dry and sandy slopes in sagebrush habitat.
Origin: Native
Flowers: April-May
Growth Duration: Perennial
Astragalus cicer – chickpea milk-vetch
Distribution: Occurring In scattered locations chiefly east of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountain states and in eastern North America.
Habitat: Roadsides, fields, dry slopes, and other disturbed areas, often where moist or wet.
Origin: Introduced from Europe
Flowers: July-August
Growth Duration: Perennial
Astragalus collinus – hill milk-vetch, hillside milk-vetch
Distribution: Occurring east of the Cascades crest in Washington; southern British Columbia to Oregon, east to west-central Idaho along the Snake and Clearwater Rivers.
Habitat: Basaltic grasslands and sagebrush deserts.
Origin: Native
Flowers: May-June
Growth Duration: Perennial
• var. collinus – hillside milk-vetch
Astragalus columbianus – Columbian milk-vetch
Distribution: Occurring east of the Cascades crest in Washington, where endemic to south-central Washington.
Habitat: Dry, open areas in shrub-steppe.
Origin: Native
Flowers: April-May
Growth Duration: Perennial
Astragalus conjunctus – basalt milk-vetch, stiff milk-vetch
Distribution: Occurring east of the Cascades crest from south-central to southeastern Washington; Washington to southeast Oregon and adjacent southwestern Idaho.
Habitat: Sagebrush grasslands to brushy slopes and ponderosa pine forest openings.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
• var. rickardii – stiff milk-vetch
Astragalus cusickii – Cusick's milk-vetch
Distribution: Occurring east of the Cascades crest in southeastern Washington; Washington to east-central Oregon, east to central Idaho.
Habitat: Sagebrush plains to grassy or rocky slopes, often on talus.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
• var. cusickii – Cusick's milk-vetch
Astragalus diaphanus – John Day milk-vetch, transparent milk-vetch
Distribution: Known historically from Klickitat County in Washington, but now thought to be extirpated; Klickitat County, Washington to Wheeler and Grant counties in Oregon.
Habitat: Gravel bars, alluvial slopes, and in thin gravelly soil overlying basaltic rock.
Origin: Native
Flowers: May-June
Growth Duration: Annual, Biennial
Astragalus falcatus – Russian milk-vetch, sickle milk-vetch
Distribution: Occurring east of the Cascades crest, where known from Whitman County in Washington; British Columbia to Washington and Montana, also in a few scattered locations across North America.
Habitat: Disturbed, open areas.
Origin: Introduced from Eurasia
Flowers: July
Growth Duration: Perennial
Astragalus filipes – basalt milk-vetch
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to northeast California, east to Nevada and Idaho.
Habitat: Sagebrush plains and lower foothills.
Origin: Native
Flowers: May-June
Growth Duration: Perennial
Astragalus geyeri – Geyer's milk-vetch
Distribution: Occurring east of the Cascades crest in south-central Washington; disjunct in British Columbia and along Columbia River of Washington and north-central Oregon; otherwise southeastern Oregon to Nevada and California, east to Montana, Wyoming, and Utah.
Habitat: Sandy desert areas, especially on dunes.
Origin: Native
Flowers: June-July
Growth Duration: Annual, Biennial
• var. geyeri – Geyer's milk-vetch
Astragalus hoodianus – Hood River milk-vetch
Distribution: Occurring in the east end of the Columbia River Gorge in Klickitat County in Washington; Klickitat County, Washington to Hood River and Wasco counties in Oregon.
Habitat: Dry, open areas in sagebrush and grasslands.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Astragalus howellii – Howell's milk-vetch
Distribution: Occurring east of the Cascades crest in the southeastern corner of Washington; southeastern Washington to north-central Oregon.
Habitat: Stony hillsides among sagebrush and bunchgrass, often over basalt.
Origin: Native
Flowers: Arpil-June
Growth Duration: Perennial
Astragalus inflexus – bent milk-vetch, hairy milk-vetch
Distribution: Occurring east of the Cascades crest in Washington; south-central Washington to Oregon, east to Idaho and Montana.
Habitat: Dry hillsides in sagebrush desert.
Origin: Native
Flowers: April-July
Growth Duration: Perennial
Astragalus kentrophyta – thistle milk-vetch, spiny milk-vetch
Distribution: Known historically from Walla Walla County but considered extirpated; southern Alberta to east-central California, east to Rocky Mountains and northern Great Plains.
Habitat: Sandy deserts to alpine ridges.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
• var. douglasii – spiny millk-vetch, thistle milk-vetch
Astragalus laxmannii – Laxmann's milk-vetch, standing milk-vetch
Distribution: Occurring in north-central and eastern Washington; Yukon Territory to Washington, east to the Rocky Mountains and Minnesota.
Habitat: Prairies to rocky foothills in sagebrush desert and ponderosa pine forest.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
• var. robustior – standing milk-vetch
Astragalus leibergii – Leiberg's milk-vetch
Distribution: Endemic to Douglas, Kittitas and Chelan counties of central Washington.
Habitat: Dry hillsides and plains, commonly in sagebrush scabland on basalt.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Astragalus lentiginosus – freckled milk-vetch, specklepod milk-vetch
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to Montana and Texas.
Habitat: Open areas, desert flats to subalpine slopes.
Origin: Native
Flowers: April-July
Growth Duration: Perennial
• var. lentiginosus – freckled milk-vetch, specklepod milk-vetch
Astragalus lyallii – Lyall's milk-vetch
Distribution: Endemic to Washington from Kittitas and Douglas counties south to Benton, east to Grant and Adams counties.
Habitat: Sagebrush and desert areas, especially on sand dunes.
Origin: Native
Flowers: May-June
Growth Duration: Perennial
Astragalus microcystis – lesser-bladder milk-vetch
Distribution: Occurring in the northeastern counties of Washington; southern British Columbia to Washington, east to Montana and Wyoming.
Habitat: Prairies and foothills to ponderosa pine forests.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Astragalus misellus – pauper milk-vetch
Distribution: Occurring east of the Cascades crest in Washington; Washington to Oregon.
Habitat: Dry, open areas in shrub-steppe.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
• var. pauper – pauper milk-vetch
Astragalus miser – weedy milk-vetch
Distribution: Occurring east of the Cascades crest in Washington; southern British Columbia to central Washington, Rocky Mountains and northern Great Plains.
Habitat: Grasslands and foothills to montane forests, dry ridges and occasionally alpine meadows.
Origin: Native
Flowers: April-July
Growth Duration: Perennial
• var. miser – weedy milk-vetch
• var. serotinus – weedy milk-vetch
Astragalus pulsiferae – Ames's milk-vetch
Distribution: Known only from Mt. Adams and Klickitat County in Washington; Occurring in the northern Sierra Nevada of California and adjacent Nevada; not reported from Oregon.
Habitat: Sandy and gravelly flats in sagebrush and open pine forests on basalt.
Origin: Native
Flowers: June-July
Growth Duration: Perennial
• var. suksdorfii – Ames's milk-vetch
Astragalus purshii – Pursh's milk-vetch, woolly-pod milk-vetch
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and northern Great Plains.
Habitat: Prairies and sagebrush deserts, foothills and lower mountains.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
• var. glareosus – woolly-pod milk-vetch
• var. purshii – Pursh's milk-vetch, woolly-pod milk-vetch
Astragalus reventiformis – Yakima milk-vetch
Distribution: Occurring east of the Cascades crest in Washington; Washington to Sherman County in Oregon.
Habitat: Shrub-steppe to low, dry, open ponderosa pine forests.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Astragalus reventus – Blue Mts. milk-vetch, longleaf milk-vetch
Distribution: Occurring east of the Cascades crest in the southeastern counties in Washington; Washington to northeastern Oregon.
Habitat: Pondersoa pine forest openings at low to moderate elevations.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Astragalus riparius – Piper's milk-vetch
Distribution: Occurring east of the Cascades crest in the southeastern counties in Washington; southeastern WA east to adjacent Idaho.
Habitat: Dry bluffs and canyon banks.
Origin: Native
Flowers: May-June
Growth Duration: Perennial
Astragalus robbinsii – Robbins's milk-vetch
Distribution: Occurring east of the Cascades crest in the northern counties in Washington; Alaska to Oregon,east to Alberta and south in the Rocky Mountains to Colorado, also in eastern North America.
Habitat: Stream banks and alpine slopes.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
• var. minor – Robbin's milk-vetch
Astragalus sclerocarpus – stalked-pod milk-vetch, The Dalles milk-vetch, woody-pod milk-vetch
Distribution: Occurring east of the Cascades crest chiefly in the Columbia River Basin and Columbia River Gorge in Washington; south-central British Columbia to north-central Oregon.
Habitat: Dunes and sandy barrens, low elevation
Origin: Native
Flowers: May-June
Growth Duration: Perennial
Astragalus sheldonii – Sheldon's milk-vetch
Distribution: Occurring east of the Cascades crest in Asotin County in Washington; southeastern Washington to Oregon, east to Idaho.
Habitat: Shrub-steppe and ponderosa pine forest openings.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Astragalus sinuatus – Whited's milk-vetch
Distribution: Endemic to Chelan County in Washington.
Habitat: Among sagebrush on rocky hillsides.
Origin: Native
Flowers: May
Growth Duration: Perennial
Astragalus spaldingii – Spalding's milk-vetch
Distribution: Occurring east of the Cascades crest in Washington; central Washington to northeast Oregon, east to western Idaho.
Habitat: Sagebrush and grasslands in the foothills and valleys.
Origin: Native
Flowers: May-June
Growth Duration: Perennial
Astragalus speirocarpus – curve-pod milk-vetch, medic milk-vetch, spiral-pod milk-vetch
Distribution: Endemic to Washington from Kittitas County south to Klickitat County, east to Grant County,
Habitat: Sagebrush desert.
Origin: Native
Flowers: April-May
Growth Duration: Perennial
Astragalus succumbens – crouching milk-vetch, sprawling milk-vetch
Distribution: Occurring east of the Cascades crest in Washington from Kittitas and Grant counties south; Washington to Umatilla and Gilliam Counties, Oregon.
Habitat: Sagebrush deserts, sandy barrens and lower foothills.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Astragalus tenellus – pulse milkvetch
Distribution: Disjunct in Douglas County in Washington; Yukon to southeastern Oregon and Nevada, east to Rocky Mountains.
Habitat: Prairies and foothills to lower mountains.
Origin: Native
Flowers: May
Growth Duration: Perennial
Astragalus tweedyi – Tweedy's milk-vetch
Distribution: Occurring east of the Cascades crest in Washington, from Yakima County south; central Washingtonto north-central Oregon near the Columbia River and lower Deschutes River.
Habitat: Sagebrush plains and foothills.
Origin: Native
Flowers: May-June
Growth Duration: Perennial
Astragalus whitneyi – balloon milk-vetch
Distribution: Occurring east of the Cascades crest in Washington; central Washington to California, east to Idaho and Nevada.
Habitat: High, open, rocky ridges and slopes, often in serpentine.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
• var. sonneanus – balloon milk-vetch
Athyrium distentifolium – alpine lady-fern
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to Alberta, Montana, Wyoming and Colorado; also in northeastern Canada and Greenland.
Habitat: Open, rocky slopes and along streams at mid- to high elevations in the mountains.
Origin: Native
Growth Duration: Perennial
• ssp. americanum – American alpine lady-fern
Athyrium filix-femina – lady-fern
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast; circumboreal.
Habitat: Moist woods, meadows, forest edge, and shaded riparian corridors from low to middle elevations.
Origin: Native
Spores: May-September
Growth Duration: Perennial
• ssp. cyclosorum – lady fern, northwestern lady fern
Athysanus pusillus – sandweed
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Montana.
Habitat: Dry, open, often grassy places.
Origin: Native
Flowers: March-June
Growth Duration: Annual
Atocion armeria – sweet William catchfly
Distribution: Occurring in scattered locations west of the Cascades crest in Washington; British Columbia to California, east across North America to the Atlantic Coast.
Habitat: Wastelots, roadsides, and other disturbed areas.
Origin: Introduced from Europe
Flowers: June-July
Growth Duration: Annual
Atriplex argentea – silver orache, silverscale orache
Distribution: Occurring east of the Cascades crest in Washington; central British Columbia to California, east to the Great Plains.
Habitat: Dry or alkaline soil.
Origin: Native
Flowers: July-September
Growth Duration: Annual, Perennial
• var. argentea – silver saltbush, silverscale
Atriplex canescens – fourwing saltbush, hoary saltbush, shadscale, wingscale
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to the Great Plains.
Habitat: Sand or gravel slopes and sagebrush flats, saline or not.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
• var. canescens – hoary saltbush
Atriplex dioica – thickleaf orache, saline saltbush
Distribution: Occurring on both sides of the Cascades crest in Washington, but particularly common along the inner and outer marine coast; Yukon Territory to California, east to the Atlantic Coast.
Habitat: Salt marshes, sea beaches and headlands, also inland on disturbed or saline ground;
Origin: Native
Flowers: June-September
Growth Duration: Annual
Atriplex gardneri – Gardner's saltbush
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and northern Great Plains.
Habitat: Sagebrush-steppe desert.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
• var. falcata – moundscale, gardner's saltbush, sickle saltbush, saltsage
Atriplex gmelinii – Gmelin's orache, Gmelin's saltbush
Distribution: Occurring west of the Cascades crest along the coast in Washington; Alaska to California.
Habitat: On coastal beaches, strands, and rocky outcroppings near the high tide in saline soil.
Origin: Native
Flowers: June-September
Growth Duration: Annual
• var. gmelinii – Gmelin's orache, Gmelin's saltbush
Atriplex heterosperma – orach, Russian atriplex orach
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and Great Plains; also in eastern North America.
Habitat: Riparian zones and adjacent fields; tolerant of alkaline.
Origin: Introduced from Eurasia
Flowers: June-August
Growth Duration: Annual
Atriplex hortensis – garden orache, French spinach
Distribution: Occurring east of the Cascades crest in Washington; Alaska to California, east to the Great Plains and in scattered locations in eastern North America.
Habitat: Disturbed areas, often where seasonally moist.
Origin: Introduced from Asia
Flowers: July-August
Growth Duration: Annual
Atriplex littoralis – grassleaf orache, narrow-leaved orache
Distribution: Occurring west of the Cascades crest in Washington; also occurring in eastern North America.
Habitat: Coastal shoreline.
Origin: Introduced from Eurasian
Flowers: June-September
Growth Duration: Annual, Perennial
Atriplex longipes – long-stalked orache, Baltic saltbush
Distribution: Occurring west of the Cascades crest in northwestern Washington; southwestern British Columbia to northwestern Washington.
Habitat: Marine gravel, mudflats.
Origin: Introduced from Eurasia
Flowers: June-September
Growth Duration: Annual
Atriplex oblongifolia – oblongleaf orache
Distribution: Occurring east of the Cascades crest in Washington; southern British Columbia to Washington, east to Alberta and Montana.
Habitat: Fields, roadsides, wastelots, and other disturbed areas.
Origin: Introduced from Europe
Flowers: June-September
Growth Duration: Annual
Atriplex patula – halberdleaf orache, spear oracle
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic.
Habitat: Coastal and inland, saline or alkaline soil.
Origin: Introduced from Eurasia
Flowers: June-September
Growth Duration: Annual
Atriplex prostrata – fat hen, hastate orache, thin-leaf orache
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, in scattered location across Canada and the U.S. to the Atlantic Coast.
Habitat: Along the coast in saline soils, beaches, and strands; inland in alkaline soils.
Origin: Introduced from Eurasia
Flowers: June-September
Growth Duration: Annual
Atriplex rosea – red orach, tumbling orach
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and Great Plains; also in scattered locations in central and eastern U.S.
Habitat: Weedy species of irrigated land and roadsides.
Origin: Introduced from Eurasia
Flowers: July-September
Growth Duration: Annual
Atriplex truncata – wedge orache, wedgeleaf orache, wedgescale orache
Distribution: Occurring east of the Cascades crest in Washington; central British Columbia to California, east to the Rocky Mountains and northern Great Plains.
Habitat: Alkaline soil, flats and shores.
Origin: Native
Flowers: June-August
Growth Duration: Annual
Atropa belladonna – belladonna, deadly nightshade
Origin: Introduced
Growth Duration: Perennial
Aubrieta deltoidea – rockcress
Habitat: Disturbed areas, where escaping from nearby cultivation.
Origin: Introduced from Europe
Flowers: April-June
Growth Duration: Perennial
Aucuba japonica
Origin: Introduced
Avena barbata – barbed oats
Distribution: Occurring chiefly west of the Cascades crest in Washington; Washington to California, east to Montana, Arizona, and New Mexico.
Habitat: Fields, roadsides, wastelots, and other disturbed areas.
Origin: Introduced Eurasian
Flowers: May-June
Growth Duration: Annual
Avena fatua – wild oats
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Fields, roadsides, wastelots, and other disturbed areas.
Origin: Introduced from Eurasia
Flowers: May-September
Growth Duration: Annual
Avena sativa – cultivated oats
Distribution: Occurring chiefly west of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Fields, roadsides, wastelots, and other disturbed areas.
Origin: Introduced from the Mediterranean region
Flowers: June-August
Growth Duration: Annual
Azolla filiculoides – duckweed fern, large mosquito fern
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to Idaho and western Montana.
Habitat: Ponds, backwaters, slow-moving streams.
Origin: Native
Growth Duration: Annual
Azolla microphylla – Mexican waterfern fern, mosquito fern
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Texas.
Habitat: Ponds and backwaters, mostly at low elevations.
Origin: Native
Growth Duration: Annual, Perennial
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