Vascular Plants

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

Browse by common name:
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Common names beginning with O:
British oak (Quercus robur)
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia to Oregon, east to Montana; also escaped in eastern North America.
Habitat: Forest edges, thickets, roadsides, and hedgerows.
Origin: Introduced from Europe/Africa
Flowers: April-June
Growth Duration: Perennial
English oak (Quercus robur)
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia to Oregon, east to Montana; also escaped in eastern North America.
Habitat: Forest edges, thickets, roadsides, and hedgerows.
Origin: Introduced from Europe/Africa
Flowers: April-June
Growth Duration: Perennial
Garry oak (Quercus garryana)
Distribution: Occurring on both sides of the Cascades crest and east in the Columbia River Gorge in Washington; Vancouver Island, British Columbia to California.
Habitat: Prairies, meadows, balds, rocky bluffs, and related open areas mostly at low elevations.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Jerusalem oak (Dysphania botrys)
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east across much of the U.S. and parts of southern Canada.
Habitat: Streambanks, gravel bars, roadsides, and other distrubed, open areas.
Origin: Introduced from Eurasia
Flowers: May-October
Growth Duration: Annual
Oregon white oak (Quercus garryana)
Distribution: Occurring on both sides of the Cascades crest and east in the Columbia River Gorge in Washington; Vancouver Island, British Columbia to California.
Habitat: Prairies, meadows, balds, rocky bluffs, and related open areas mostly at low elevations.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Red oak (Quercus rubra)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Idaho; native to central and eastern North America.
Habitat: Disturbed forest edge, fields, and wastelots.
Origin: Introduced from central and eastern North America
Flowers: April-June
Growth Duration: Perennial
Pacific oak-fern (Gymnocarpium disjunctum)
Distribution: Occurring in forested areas on both sides of the Cascades crest except in southeastern Washington; Alaska to Oregon, east to Alberta, Idaho, and Montana, and disjunct in Wyoming; circumboreal.
Habitat: Moist woods, streambanks and wet cliffs.
Origin: Native
Growth Duration: Perennial
Western oak-fern (Gymnocarpium disjunctum)
Distribution: Occurring in forested areas on both sides of the Cascades crest except in southeastern Washington; Alaska to Oregon, east to Alberta, Idaho, and Montana, and disjunct in Wyoming; circumboreal.
Habitat: Moist woods, streambanks and wet cliffs.
Origin: Native
Growth Duration: Perennial
Bulbous oatgrass (Arrhenatherum elatius)
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
California oatgrass (Danthonia californica)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Open, grassy meadows to rocky ridges, from coastal prairies to mid-elevations in the mountains, often with ponderosa pine.
Origin: Native
Flowers: June-July
Growth Duration: Perennial
Few-flower oatgrass (Danthonia unispicata)
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the northern Rocky Mountains and northern Great Plains.
Habitat: Dry to occasionally moist prairies, foothills, and open parks and ridges in mountain forests.
Origin: Native
Flowers: June-July
Growth Duration: Perennial
One-spike oatgrass (Danthonia unispicata)
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the northern Rocky Mountains and northern Great Plains.
Habitat: Dry to occasionally moist prairies, foothills, and open parks and ridges in mountain forests.
Origin: Native
Flowers: June-July
Growth Duration: Perennial
Poverty oatgrass (Danthonia spicata)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to Oregon, east to Newfoundland and eastern United States.
Habitat: Sandy to rocky soil in dry woods and fairly dry meadows.
Origin: Native
Flowers: June-July
Growth Duration: Perennial
Timber oatgrass (Danthonia intermedia)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains, Great Plains, and eastern Canada; also in eastern Russia.
Habitat: Dry, mesic or wet meadows, peatlands, rocky slopes, and talus, from the lowlands to alpine.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Barbed oats (Avena barbata)
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
Cultivated oats (Avena sativa)
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
Wild oats (Avena fatua)
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
Creambush ocean-spray (Holodiscus discolor)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and Texas.
Habitat: Gravelly soil in open, dry to moist woods, coastal bluffs to moderate elevations in the mountains.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Hillside ocean-spray (Holodiscus discolor)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and Texas.
Habitat: Gravelly soil in open, dry to moist woods, coastal bluffs to moderate elevations in the mountains.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Ocean-spray (Holodiscus discolor)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and Texas.
Habitat: Gravelly soil in open, dry to moist woods, coastal bluffs to moderate elevations in the mountains.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Oenanthe (Oenanthe sarmentosa)
Distribution: Occurring chiefly west of the Cascades crest in Washington; Alaska to California.
Habitat: Low elevation wet areas, often in standing water.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Old man in the spring (Senecio vulgaris)
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: Roadsides, waste ground, lawns, and other disturbed, open sites.
Origin: Introduced from Europe
Flowers: February-September
Growth Duration: Annual
Old-man's beard (Clematis vitalba)
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia to Oregon, also in scattered locations in eastern North America.
Habitat: Forest edge, hillsides, parks, wastelots, and other disturbed sites.
Origin: Introduced; native to Europe and Africa
Flowers: June-September
Growth Duration: Perennial
Oldman (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
Oldwoman (Artemisia stelleriana)
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
Autumn olive (Elaeagnus umbellata)
Distribution: Occurring in scattered locations on both sides of the Cascades crest in Washington; British Columbia to Oregon, also in Montana; central and eastern North America.
Habitat: Introduced from eastern Asia as ornamental shrub, occasionally escaping in disturbed areas and waste ground.
Origin: Introduced from eastern Asia
Flowers: June-July
Growth Duration: Perennial
Blue Mountain onion (Allium dictuon)
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
Columbia onion (Allium columbianum)
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
Cuddy Mountain onion (Allium fibrillum)
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
Douglas' onion (Allium douglasii)
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
Fragile onion (Allium scilloides)
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
Fringed onion (Allium fibrillum)
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
Geyer's onion (Allium geyeri)
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
Grand Coulee onion (Allium constrictum)
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
Narrow-leaf onion (Allium amplectens)
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
Nevius's onion (Allium nevii)
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
Nodding onion (Allium cernuum)
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
Pacific onion (Allium validum)
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
Robinson's onion (Allium robinsonii)
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
Rock onion (Allium macrum)
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
Rosy Sierra onion (Allium campanulatum)
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
Scalloped onion (Allium crenulatum)
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
Scilla-like onion (Allium scilloides)
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
Swamp onion (Allium validum)
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
Taper-tip onion (Allium acuminatum)
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
Textile onion (Allium textile)
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
Tolmie's onion (Allium tolmiei)
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
White wild onion (Allium textile)
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
Alaska oniongrass (Melica subulata)
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 slopes to thick, dry or moist woods, from near sea level to middle elevations in the mountains.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Bulbous oniongrass (Melica bulbosa)
Distribution: Occurring east of the Cascades crest in Washington;
Habitat: Grassland, sagebrush, open forest, rocky slopes, and talus.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Ookow (Dichelostemma congestum)
Distribution: Occurring west of the Cascades crest and east in the Columbia River Gorge in Washington; Washington to California.
Habitat: Grassy meadows, rocky prairies and sagebrush slopes.
Origin: Native
Flowers: May-June
Growth Duration: Perennial
Orach (Atriplex heterosperma)
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
Red orach (Atriplex rosea)
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
Russian atriplex orach (Atriplex heterosperma)
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
Tumbling orach (Atriplex rosea)
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
Garden orache (Atriplex hortensis)
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
Gmelin's orache (Atriplex gmelinii)
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
Grassleaf orache (Atriplex littoralis)
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
Halberdleaf orache (Atriplex patula)
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
Hastate orache (Atriplex prostrata)
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
Long-stalked orache (Atriplex longipes)
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
Narrow-leaved orache (Atriplex littoralis)
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
Oblongleaf orache (Atriplex oblongifolia)
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
Silver orache (Atriplex argentea)
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
Silverscale orache (Atriplex argentea)
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
Thickleaf orache (Atriplex dioica)
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
Thin-leaf orache (Atriplex prostrata)
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
Wedge orache (Atriplex truncata)
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
Wedgeleaf orache (Atriplex truncata)
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
Wedgescale orache (Atriplex truncata)
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
Spear oracle (Atriplex patula)
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
Canyon bog orchid (Platanthera sparsiflora)
Distribution: south-central Washington to Baja California, east to Colorado and New Mexico.
Habitat: Wet meadows, fens, and seeps.
Origin: Native
Growth Duration: Perennial
Canyon bog orchid (Platanthera stricta)
Distribution: Widely distributed on both sides of the Cascades crest in Washington; Alaska to California, east to Alberta, Montana, and Wyoming.
Habitat: Wet meadows, swamps and coniferous forests, low to mid-elevations.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Choriso bog orchid (Platanthera chorisiana)
Distribution: Occurring west of the Cascades crest, where known only from Snohomish County in Washington; Aleutian Islands to Vancouver Island, British Columbia, and in Snohomish County, Washington.
Habitat: Moist areas, especially at the edges of streams and bogs.
Origin: Native
Flowers: July-August
Growth Duration: Perennial
Dense orchid (Platanthera elongata)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Idaho and Montana.
Habitat: Dry, open forest from low to middle elevations.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
Dense-flower rein orchid (Platanthera elongata)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Idaho and Montana.
Habitat: Dry, open forest from low to middle elevations.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
Eagle rein orchid (Platanthera aquilonis)
Distribution: Occurring east of the Cascades crest in Washington in north-central and northeastern Washington; Alaska to Oregon, east across the northern half of North America to the Atlantic Coast.
Habitat: Wet meadows from the montane to subalpine.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Fen orchid (Liparis loeselii)
Distribution: Occurring east of the Cascades crest in Washington in south-central Washington; Northwest Territory to Washington, east to Montana; also from Canadian Great Plains to eastern North America where more common; also in western and central Europe.
Habitat: Around springs and in bogs.
Origin: Native
Flowers: July-August
Growth Duration: Perennial
Frog orchid (Dactylorhiza viridis)
Distribution: Known only from Okanogan County in Washington; Alaska to Washington, east to the Rocky Mountains, Great Plains, Great Lakes region, and eastern North America.
Habitat: Moist to wet meadows at moderate elevations.
Origin: Native
Flowers: July-August
Growth Duration: Perennial
Large round-leaf orchid (Platanthera orbiculata)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to Oregon, east across Canada and the northern U.S. to the Atlantic Coast, also in the southeastern U.S.
Habitat: Moist, mossy forests.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Long-bracted green orchid (Dactylorhiza viridis)
Distribution: Known only from Okanogan County in Washington; Alaska to Washington, east to the Rocky Mountains, Great Plains, Great Lakes region, and eastern North America.
Habitat: Moist to wet meadows at moderate elevations.
Origin: Native
Flowers: July-August
Growth Duration: Perennial
Needle-spur green orchid (Platanthera stricta)
Distribution: Widely distributed on both sides of the Cascades crest in Washington; Alaska to California, east to Alberta, Montana, and Wyoming.
Habitat: Wet meadows, swamps and coniferous forests, low to mid-elevations.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Phantom orchid (Cephalanthera austiniae)
Distribution: Occurring on both sides of the Cascades crest and in the Blue Mountains in Washington; British Columbia to California, east to Idaho.
Habitat: Generally deep coniferous woods where somewhat moist.
Origin: Native
Flowers: June-July
Growth Duration: Perennial
Royal rein orchid (Platanthera transversa)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia south to California.
Habitat: Forest understory from low to middle elevations.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
Sheviak's bog orchid (Platanthera aquilonis)
Distribution: Occurring east of the Cascades crest in Washington in north-central and northeastern Washington; Alaska to Oregon, east across the northern half of North America to the Atlantic Coast.
Habitat: Wet meadows from the montane to subalpine.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Slender bog orchid (Platanthera stricta)
Distribution: Widely distributed on both sides of the Cascades crest in Washington; Alaska to California, east to Alberta, Montana, and Wyoming.
Habitat: Wet meadows, swamps and coniferous forests, low to mid-elevations.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
White orchid (Platanthera dilatata)
Distribution: Widely distributed on both sides of the Cascades crest through the mountainous and forested areas of Washington; Alaska to California, east to the Rocky Mountains; also from the Great Lakes region east to the Atlantic Coast.
Habitat: Wet meadows, forest openings, and streambanks from low elevations to the subalpine.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
Cascade Oregon-grape (Mahonia nervosa)
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia to California, east to western Montana.
Habitat: Generally in light woodland and forest edge.
Origin: Native
Flowers: April-May
Growth Duration: Perennial
Creeping Oregon-grape (Mahonia repens)
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia south to California, east to the Rocky Mountains.
Habitat: Sagebrush valleys to open forested slopes.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Dull Oregon-grape (Mahonia nervosa)
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia to California, east to western Montana.
Habitat: Generally in light woodland and forest edge.
Origin: Native
Flowers: April-May
Growth Duration: Perennial
Holly-leaf Oregon-grape (Mahonia aquifolium)
Distribution: Occurring on both sides of the Cascades crest in Washington; southern British Columbia to Northern California, east to northern Idaho and western Montana.
Habitat: Sagebrush slopes and open woods.
Origin: Native
Flowers: March-May
Growth Duration: Perennial
Low Oregon-grape (Mahonia repens)
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia south to California, east to the Rocky Mountains.
Habitat: Sagebrush valleys to open forested slopes.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Shining Oregon-grape (Mahonia aquifolium)
Distribution: Occurring on both sides of the Cascades crest in Washington; southern British Columbia to Northern California, east to northern Idaho and western Montana.
Habitat: Sagebrush slopes and open woods.
Origin: Native
Flowers: March-May
Growth Duration: Perennial
Tall Oregon-grape (Mahonia aquifolium)
Distribution: Occurring on both sides of the Cascades crest in Washington; southern British Columbia to Northern California, east to northern Idaho and western Montana.
Habitat: Sagebrush slopes and open woods.
Origin: Native
Flowers: March-May
Growth Duration: Perennial
Oregon-tea (Clinopodium douglasii)
Distribution: Occurring chiefly west of the Cascades crest in Washington; Alaska to California, east to Montana.
Habitat: Coniferous woods, from sea level to middle elevations in the mountains.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Cockscomb oreocarya (Oreocarya glomerata)
Distribution: Occurring east of the Cascades crest and in the Columbia River Gorge in Washington; southern British Colombia to California, east to the northern Great Plains and Colorado.
Habitat: Dry, open places in the valleys, plains and foothills, occasionally higher.
Origin: Native
Flowers: April-July
Growth Duration: Biennial, Perennial
Gray oreocarya (Oreocarya leucophaea)
Distribution: Occurring east of the Cascades in central and south-central Washington, where endemic.
Habitat: Dry, usually sandy places at low elevations.
Origin: Native
Flowers: May-June
Growth Duration: Biennial, Perennial
Snake River oreocarya (Oreocarya spiculifera)
Distribution: Occurring east of the Cascades crest in Washington; Washington to Oregon and Nevada, east to Idaho, Montana, Wyoming, and Utah.
Habitat: Dry, open slopes and flats in the plains, valleys and foothills.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Thompson's oreocarya (Oreocarya thompsonii)
Distribution: Occurring east of the Cascades crest in Washington, where endemic to the Wenatchee Mountains and nearby areas.
Habitat: Middle elevations in the mountains
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Osage-orange (Maclura pomifera)
Distribution: Occurring east of the Cascades crest in southeastern Washington; south-central Washington to California, east to west-central Idaho, native from the south-central U.S. to the mid-Atlantic states.
Habitat: Open, disturbed areas, often along riparian corridors or abandoned fields.
Origin: Introduced from elsewhere in United States
Flowers: May-June
Growth Duration: Perennial
Purple osier (Salix purpurea)
Distribution: Occurring in scattered lowland locations west of the Cascades crest in Washington; British Columbia to California, also in Utah, and from the central U.S. and Canada to the Atlantic Coast.
Habitat: Ditches, floodplains, and shores.
Origin: Introduced from Europe
Flowers: April-May
Growth Duration: Perennial
Western red osier (Cornus occidentalis)
Distribution: Occurring on both sides of the Cascades crest in Washington, through more common west of the crest; Alaska to California, east to Idaho, western Montana, and Nevada.
Habitat: Moist soil, especially along streams, from low to middle elevations.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Oso-berry (Oemleria cerasiformis)
Distribution: Occurring west of the Cascades crest and east in the Columbia River Gorge in Washington; British Columbia to California.
Habitat: Moist to dry, open forest, forest edge, and stream bank thickets at low elevation.
Origin: Native
Flowers: February-April
Growth Duration: Perennial
Ovalpurse (Hornungia procumbens)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains, central Canada, and Newfoundland.
Habitat: Open areas where seasonally moist.
Origin: Introduced from Europe, North Africa, and Asia
Flowers: March-June
Growth Duration: Annual
Dwarf owl-clover (Triphysaria pusilla)
Distribution: Occurring west of the Cascades crest and east in the Columbia River Gorge in Washington; southwestern British Columbia to California.
Habitat: Vernally moist, open ground at low elevations.
Origin: Native
Flowers: April-June
Growth Duration: Annual
Golden-tongue owl-clover (Orthocarpus luteus)
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains, northern Great Plains, and Great Lakes region.
Habitat: Low ground, from the plains to moderate elevations in the mountains.
Origin: Native
Flowers: June-August
Growth Duration: Annual
Grand Coulee owl-clover (Orthocarpus barbatus)
Distribution: Occurring east of the Cascades crest in Washington. southern British Columbia to Washington.
Habitat: Dry, open ground in sagebrush-steppe.
Origin: Native
Flowers: May-June
Growth Duration: Annual
Mountain owl-clover (Orthocarpus imbricatus)
Distribution: Occurring west of the Cascades crest in the Olympic Mountains; British Columbia to Oregon and California.
Habitat: Fairly dry meadows and rocky slopes, mid- to high elevations in the mountains.
Origin: Native
Flowers: July-September
Growth Duration: Annual
Narrow-leaved owl-clover (Orthocarpus tenuifolius)
Distribution: Occurring east of the Cascades crest in Washington; southern British Columbia to central Oregon, east to western Montana.
Habitat: Open, moist or rather dry places, from the valleys and plains to moderate elevtions in the mountains.
Origin: Native
Flowers: May-August
Growth Duration: Annual
Paintbrush owl-clover (Castilleja ambigua)
Distribution: Occurring west of the Cascades crest along the coast in Washington; southwestern British Columbia to California.
Habitat: Margins of coastal salt marshes and brackish areas.
Origin: Native
Flowers: June-September
Growth Duration: Annual
Rosy owl-clover (Orthocarpus bracteosus)
Distribution: Occurring chiefly east of the Cascades crest in Washington; southern British Columbia to northern California.
Habitat: Meadows at low elevations.
Origin: Native
Flowers: June-August
Growth Duration: Annual
Thin-leaved owl-clover (Orthocarpus tenuifolius)
Distribution: Occurring east of the Cascades crest in Washington; southern British Columbia to central Oregon, east to western Montana.
Habitat: Open, moist or rather dry places, from the valleys and plains to moderate elevtions in the mountains.
Origin: Native
Flowers: May-August
Growth Duration: Annual
Hawkweed oxtongue (Picris hieracioides)
Distribution: Occurring in the Columbia River Gorge in Washington; British Columbia to Washington; also in eastern North America.
Origin: Introduced from Europe
Growth Duration: Biennial, Perennial