Absinthe (Artemisia absinthium)
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

Northern adder's-tongue (Ophioglossum pusillum)
Distribution: Alaska to California, and Montana east to Maine and Virginia
Habitat: Meadows and woods at moderate elevations in the mountains
Origin: Native
Growth Duration: Perennial

Annual agoseris (Agoseris heterophylla)
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

Large-flowered agoseris (Agoseris grandiflora)
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

Orange agoseris (Agoseris aurantiaca)
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

Seaside agoseris (Agoseris apargioides)
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

Sierra Nevada agoseris (Agoseris monticola)
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

Tall agoseris (Agoseris ×elata)
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

Black alder (Alnus glutinosa)
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

Green alder (Alnus viridis)
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

Mountain alder (Alnus viridis)
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

White alder (Alnus rhombifolia)
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

Alfalfa (Medicago sativa)
Distribution: Widely distributed on both sides of the Cascades crest in Washington; Alaska to California, east to the Atlantic Coast.
Habitat: Roadsides, fields, wastelots, and other disturbed, open areas; often escaping from commercial cultivation.
Origin: Introduced
Flowers: May-October
Growth Duration: Annual, Perennial

Coast alkaligrass (Puccinellia maritima)
Origin: Introduced

Common alkanet (Anchusa officinalis)
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

Italian alkanet (Anchusa azurea)
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

Almond (Prunus dulcis)
Distribution: Occurring in scattered locations east of the Cascades crest and in the Columbia River Gorge in Washington; Washington, Idaho, and California.
Habitat: Disturbed areas, mostly along riparian zones and rocky slopes.
Origin: Introduced from western Asia and northern Africa
Flowers: March-May
Growth Duration: Perennial

Small alpinegold (Hulsea nana)
Distribution: Occurring on both sides of the Cascades crest in Washington from Mount Rainier south; central Washington to California (not in northeastern Oregon).
Habitat: Generally around volcanic mountains above timberline.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Crevice alumroot (Heuchera micrantha)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Idaho.
Habitat: Gravelly stream banks, rock crevices and talus slopes, sea level to subalpine.
Origin: Native
Flowers: May-August
Growth Duration: Perennial

Green-flowered alumroot (Heuchera chlorantha)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to Oregon.
Habitat: Gravelly prairies and wooded hillsides.
Origin: Native
Flowers: May-August
Growth Duration: Perennial

Meadow alumroot (Heuchera chlorantha)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to Oregon.
Habitat: Gravelly prairies and wooded hillsides.
Origin: Native
Flowers: May-August
Growth Duration: Perennial

Roundleaf alumroot (Heuchera cylindrica)
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to Alberta, Wyoming, and Nevada.
Habitat: Rocky soil, cliffs and talus slopes, foothills to the subalpine.
Origin: Native
Flowers: April-August
Growth Duration: Perennial

Smooth alumroot (Heuchera glabra)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to Oregon.
Habitat: Streambanks and moist rocks, from the coast to above timberline
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Desert alyssum (Alyssum desertorum)
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

Small alyssum (Alyssum alyssoides)
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

Argentina amaranth (Amaranthus deflexus)
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

Green amaranth (Amaranthus hybridus)
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

Hybrid amaranth (Amaranthus hybridus)
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

Pale amaranth (Amaranthus blitum)
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

Smooth amaranth (Amaranthus hybridus)
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

Bristly amsinckia (Amsinckia tessellata)
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

Cliff anemone (Anemone multifida)
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

Little mountain anemone (Anemone lyallii)
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

Northern anemone (Anemone parviflora)
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

Pacific anemone (Anemone multifida)
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

Small-flowered anemone (Anemone parviflora)
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

Canby's angelica (Angelica canbyi)
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

Kneeling angelica (Angelica genuflexa)
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

Seacoast angelica (Angelica lucida)
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

Woolly angelica (Angelica hendersonii)
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

Queen Anne's-lace (Daucus carota)
Distribution: Widely distributed on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Roadsides, fields, ditches, meadows, lawns, and other disturbed open areas.
Origin: Introduced from Europe
Flowers: June-September
Growth Duration: Biennial

Antelope-brush (Purshia tridentata)
Distribution: Widely distributed east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and Nebraska.
Habitat: Sagebrush desert and shrub-steppe to ponderosa pine forests.
Origin: Native
Flowers: April-June
Growth Duration: Perennial

Apargidium (Microseris borealis)
Distribution: Occurring west of the Cascades crest in Washington; southern Alaska to northern California.
Habitat: Sphagnum bogs and wet meadows in the mountains.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Dawson apple (Malus ×dawsoniana)
Distribution: Occurring west of the Cascades crest in Washington; Washington to Oregon.
Habitat: Fields, thickets, open damp forests, sea bluffs, roadsides, wastelots, and abandoned homesteads.
Origin: Escaping from cultivation
Flowers: April-May
Growth Duration: Perennial

Sacred thorn apple (Datura wrightii)
Distribution: Scattered locations across Washington; California east across the U.S. to New England.
Habitat: Disturbed, dry, open areas, roadsides, and waste places.
Origin: Introduced from Mexico
Flowers: June-August
Growth Duration: Annual

Apricot (Prunus armeniaca)
Distribution: Occurring in scattered locations on both sides of the Cascades crest in Washington; southern British Columbia to California, east to the Rocky Mountains, and in scattered areas eastward to the Atlantic Coast.
Habitat: Sagebrush desert, ledges, gravel or clay slopes, thickets, and shorelines
Origin: Introduced from China
Flowers: March-May
Growth Duration: Perennial

Broad-leaved arnica (Arnica latifolia)
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

Clasping arnica (Arnica lanceolata)
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

Hairy arnica (Arnica mollis)
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

Hillside arnica (Arnica fulgens)
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

Longleaf arnica (Arnica longifolia)
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

Mountain arnica (Arnica latifolia)
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

Nevada arnica (Arnica nevadensis)
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

Parry's arnica (Arnica parryi)
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

Rydberg's arnica (Arnica rydbergii)
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

Sierra arnica (Arnica nevadensis)
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

Slender arnica (Arnica gracilis)
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

Sticky-leaf arnica (Arnica ovata)
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

Subalpine arnica (Arnica rydbergii)
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

Awl-leaf arrow-grass (Triglochin scilloides)
Distribution: Occurring chiefly west of the Cascades crest along the coastal counties in Washington; British Columbia to Baja California, Mexico, east to the Rocky Mountains and northern Great Plains; also in South America.
Habitat: Generally in shallow water, but often stranded in mud at edge of receding ponds, coastal tideflats to interior valleys.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Marsh arrow-grass (Triglochin palustris)
Origin: Native
Flowers: June - August
Growth Duration: Perennial

Arumleaf arrowhead (Sagittaria cuneata)
Distribution: East of the Cascades in Washington; British Columbia south to California, east to New York.
Habitat: Ponds, lake shores and ditches.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Common arrowhead (Sagittaria latifolia)
Distribution: Occurring on both sides of the Cascades in Washington; Vancouver Island, British Columbia to central California; central North America to the Atlantic Coast.
Habitat: Ditches, ponds, lakes, swampy areas.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Grassy arrowhead (Sagittaria graminea)
Distribution: Occurring west of the Cascades crest in Washington; Great Plains to the Atlantic Coast.
Habitat: Wetlands, ponds, and lakes
Origin: Introduced from central and eastern North America
Flowers: June-August
Growth Duration: Perennial

Sessile-fruited arrowhead (Sagittaria rigida)
Distribution: Occurring in lowland areas west of the Cascades crest in Washington; California; central U.S. and southern Canada east to northeastern U.S. and Canada; scattered locations elsewhere in U.S. and Canada.
Habitat: Pond and lake margins.
Origin: Introduced from eastern North America
Flowers: June-August
Growth Duration: Perennial

Arugula (Eruca vesicaria)
Distribution: Occurring in scattered locations on both sides of the Cascades crest British Columbia to California, east across most of North America to the Atlantic Coast.
Habitat: Grain fields and waste ground.
Origin: Introduced from Eurasia
Flowers: May-June
Growth Duration: Annual

Italian arum (Arum italicum)
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

Greene's mountain ash (Sorbus scopulina)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains and northern Great Plains.
Habitat: Open areas, from middle elevations to the subalpine.
Origin: Native
Flowers: May-August
Growth Duration: Perennial

Asparagus (Asparagus officinalis)
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

Western asphodel (Triantha occidentalis)
Distribution: Occurring in the Olympic and Cascade mountains in Washington; British Columbia to California.
Habitat: Moist meadows, bogs and streambanks, mid- to high elevations in the mountains.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Alkali aster (Symphyotrichum frondosum)
Distribution: British Columbia to California, esat to Idaho, Wyoming, Colorado, and New Mexico.
Habitat: Moist, usually saline soil, often along the shores of lakes and ponds, or in vernally moist, alkaline bottoms.
Origin: Native
Flowers: August-October
Growth Duration: Annual, Perennial

Alpine leafybract aster (Symphyotrichum foliaceum)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Open, usually moist areas, low to high elevations in the mountains.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Arctic aster (Eurybia sibirica)
Distribution: Occurring west of the Cascades crest in Washington; Alaska to Washington, east to Northwest Territory, Nunavut, Alberta, Idaho, and Montana.
Habitat: Rocky outcroppings, open slopes, and meadows in the subalpine and alpine.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Canby's leafybract aster (Symphyotrichum foliaceum)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Open, usually moist areas, low to high elevations in the mountains.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Columbian white-topped aster (Sericocarpus rigidus)
Distribution: Occurring west of the Cascades crest in lowland Washington; southern Vancouver Island to southwest Oregon.
Habitat: Prairies and open areas at low elevations.
Origin: Native
Flowers: July-August
Growth Duration: Perennial

Common California aster (Symphyotrichum chilense)
Distribution: Occurring west of the Cascades crest in Washington; British Columbia to California.
Habitat: Coastal, bluffs, grasslands, open slopes, salt marsh margins, and disturbed ground.
Origin: Native
Flowers: July-October
Growth Duration: Perennial

Cusick's aster (Symphyotrichum foliaceum)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Open, usually moist areas, low to high elevations in the mountains.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Douglas's aster (Symphyotrichum subspicatum)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Alberta, Montana and Idaho.
Habitat: Moist woods, streambanks and seashores.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Engelmann's aster (Eucephalus engelmannii)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to Nevada, east to Alberta, Montana, Wyoming, and Colorado.
Habitat: Open woods and slopes, from foothills to high elevations in the mountains.
Origin: Native
Flowers: June-September
Growth Duration: Perennial

Geyer's aster (Symphyotrichum laeve)
Distribution: Occurring east of the Cascades crest in eastern Washington; Yukon Territory to California, east across most of North America to the Atlantic Coast.
Habitat: Open places in the plains and valleys to middle elevations in the mountains.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Hairy aster (Symphyotrichum pilosum)
Distribution: Occurring in scattered locations east of the Cascades crest in Washington; southwestern British Columbia to Washington, otherwise native from the U.S. Great Plains east to the Atlantic Coast.
Habitat: River cobbles, gravel, disturbed ground, and railroads.
Origin: Introduced from central and eastern North America
Flowers: August-October
Growth Duration: Perennial

Heath-leaved aster (Symphyotrichum ericoides)
Distribution: Occurring chiefly east of the Cascades crest in Washington; southern British Columbia to Oregon, east to the Rocky Mountains, and further east across Canada and most of North America to the Atlantic Coast.
Habitat: Open, wet or dry places in the valleys and plains; tolerant of alkali.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Hybrid aster (Symphyotrichum ×amethystinum)
Origin: Introduced
Growth Duration: Perennial

Intermountain aster (Symphyotrichum ascendens)
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to the Rocky Mountains and northern Great Plains.
Habitat: Meadows, grasslands, and forest openings, often where moist.
Origin: Native
Flowers: July-October
Growth Duration: Perennial

Klickitat aster (Eucephalus glaucescens)
Distribution: Endemic to the Mt. Adams area on both sides of the Cascades crest in Washington.
Habitat: Forest openings and meadows at low to middle elevations.
Origin: Native
Flowers: July-October
Growth Duration: Perennial

Leafy aster (Symphyotrichum foliaceum)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Open, usually moist areas, low to high elevations in the mountains.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Leafybract aster (Symphyotrichum foliaceum)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Open, usually moist areas, low to high elevations in the mountains.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Marsh aster (Symphyotrichum lanceolatum)
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east across North America to the Atlantic Coast.
Habitat: Moist meadows, sometimes where saline, shores, and open forest at low to middle elevations.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

New York aster (Symphyotrichum novi-belgii)
Habitat: Pond and lake margins at low to middle elevations.
Origin: Introduced from eastern North America
Flowers: August-September
Growth Duration: Perennial

Olympic Mountain aster (Eucephalus paucicapitatus)
Distribution: Occurring in the Olympic Mountains in Washington; Vancouver Island, British Columbia to the Olympic Mountains in Washington.
Habitat: Open slopes, from middle to high elevations in the mountains.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Oregon white-topped aster (Sericocarpus oregonensis)
Distribution: Occurring in the Columbia River Gorge in Washington; Washington to California.
Habitat: Grasslands, forest openings, and savanna.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Palouse aster (Symphyotrichum jessicae)
Distribution: Occurring east of the Cascades crest in eastern Washington; eastern Washington to adjacent western Idaho.
Habitat: Streambanks and open places.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Rayless alkali aster (Symphyotrichum ciliatum)
Distribution: Occurring east of the Cascades crest in northern Washington; British Columbia to northern Washington, east across Canada and the northern U.S. to the Atlantic Coast.
Habitat: Moist to dry open forest and meadows.
Origin: Native
Flowers: August-September
Growth Duration: Perennial

Rigid white-topped aster (Sericocarpus rigidus)
Distribution: Occurring west of the Cascades crest in lowland Washington; southern Vancouver Island to southwest Oregon.
Habitat: Prairies and open areas at low elevations.
Origin: Native
Flowers: July-August
Growth Duration: Perennial

Rough-leaved aster (Eurybia radulina)
Distribution: Occurring east of the Cascades crest and in the Columbia River Gorge in Washington; British Columbia to California.
Habitat: Rocky outcroppings, forest edges and openings at low to middle elevations.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Short rayed aster (Symphyotrichum frondosum)
Distribution: British Columbia to California, esat to Idaho, Wyoming, Colorado, and New Mexico.
Habitat: Moist, usually saline soil, often along the shores of lakes and ponds, or in vernally moist, alkaline bottoms.
Origin: Native
Flowers: August-October
Growth Duration: Annual, Perennial

Slender white aster (Symphyotrichum boreale)
Distribution: Occurring east of the Cascades crest in northeastern Washington; Alaska to Washington, east across Canada and the northern U.S. to the Atlantic Coast.
Habitat: Cold bogs.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Subalpine aster (Eurybia merita)
Distribution: Occurring west of the Cascades crest in Washington; British Columbia to California, east to Montana, Wyoming, Utah, and the northern Great Plains.
Habitat: Open, mesic or dry, rocky areas in the subalpine.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Tufted white prairie aster (Symphyotrichum ericoides)
Distribution: Occurring chiefly east of the Cascades crest in Washington; southern British Columbia to Oregon, east to the Rocky Mountains, and further east across Canada and most of North America to the Atlantic Coast.
Habitat: Open, wet or dry places in the valleys and plains; tolerant of alkali.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Western aster (Symphyotrichum ascendens)
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to the Rocky Mountains and northern Great Plains.
Habitat: Meadows, grasslands, and forest openings, often where moist.
Origin: Native
Flowers: July-October
Growth Duration: Perennial

Western meadow aster (Symphyotrichum campestre)
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to Alberta, Montana, Wyoming, and Colorado.
Habitat: Dry to moist forest openings, shorelines, and other open areas from low to middle elevations.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Western showy aster (Eurybia conspicua)
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to Oregon, east to the northern Rocky Mountains and northern Great Plains.
Habitat: Open woods, from foothills to middle elevations in the mountains.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

White-topped aster (Sericocarpus rigidus)
Distribution: Occurring west of the Cascades crest in lowland Washington; southern Vancouver Island to southwest Oregon.
Habitat: Prairies and open areas at low elevations.
Origin: Native
Flowers: July-August
Growth Duration: Perennial

Large-leaved avens (Geum macrophyllum)
Distribution: Widely distributed on both sides of the Cascades crest in Washington; Alaska to Baja California, east to the Great Plains and east across Canada to the Atlantic Coast.
Habitat: Common in moist woods and meadows from sea level to subalpine.
Origin: Native
Flowers: April-August
Growth Duration: Perennial

Ross's avens (Geum rossii)
Distribution: Occurring east of the Cascades crest in the Wenatchee Mountains in Washington; Alaska to California, east to the Rocky Mountains, and eastward across northern Canada to Greenland; also in Far East Russia.
Habitat: Arctic tundra, high gravelly meadows and scree slopes.
Origin: Native
Flowers: June- August
Growth Duration: Perennial

Yellow avens (Geum aleppicum)
Distribution: Occurring east of the Cascades crest in Washington; Alaska to California, east across Canada and the U.S., except the south-central and southeast regions, to the Atlantic Coast.
Habitat: Shores, streams, damp thickets, damp forests, wet meadows, and peatlands.
Origin: Native
Flowers: June-July
Growth Duration: Perennial

False azalea (Rhododendron menziesii)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to Alberta, Idaho, Montana, and Wyoming.
Habitat: Forest understory and edges from middle elevations to the subalpine.
Origin: Native
Flowers: April-June
Growth Duration: Perennial