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)
Origin: Introduced from Europe/Africa
English oak (Quercus robur)
Origin: Introduced from Europe/Africa
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
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
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
Red oak (Quercus rubra)
Origin: Introduced from central and eastern NA
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
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
Barbed oat (Avena barbata)
Distribution: Introduced and common in southwest United States; occasional in Washington and western Oregon.
Habitat: Roadsides and waste land.
Origin: Introduced
Flowers: May - June
Beardless false oat (Graphephorum wolfii)
Origin: Native
Flowers: June - August
Narrow false oat (Trisetum spicatum)
Distribution: Occurring in the mountainous areas on both sides of the Cascades crest throughout Washington; Alaska to California, east to the Rocky Mountains, northern Great Plains, further east to the Great Lakes region and eastern North America.
Habitat: Montane forests to alpine slopes in rocky, dry or moist areas.
Origin: Native
Flowers: June-September
Oat (Avena sativa)
Distribution: Commonly cultivated throught the United States and Canada, occasionally escaping but usually not persisting.
Habitat: Roadsides and field margins.
Origin: Introduced
Flowers: June - August
Tall false oat (Trisetum canescens)
Origin: Native
Flowers: May - July
Wild oat (Avena fatua)
Distribution: Common introduction in most of western North America.
Habitat: A weed in grain fields, roadsides and waste ground.
Origin: Introduced
Flowers: May - September
Yellow false oat (Trisetum flavescens)
Origin: Introduced
California oatgrass (Danthonia californica)
Distribution: British Columbia south on both sides of the Cascades to California, east to Montana and New Mexico.
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
Few-flower oatgrass (Danthonia unispicata)
Distribution: British Columbia south on both sides of the Cascades to California, east to Alberta and Colorado.
Habitat: Dry to occasionally moist prairies, foothills, and open parks and ridges in mountain forests.
Origin: Native
Flowers: June - July
One-spike oatgrass (Danthonia unispicata)
Distribution: British Columbia south on both sides of the Cascades to California, east to Alberta and Colorado.
Habitat: Dry to occasionally moist prairies, foothills, and open parks and ridges in mountain forests.
Origin: Native
Flowers: June - July
Poverty oatgrass (Danthonia spicata)
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia south on both sides of the Cascades 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
Tall oatgrass (Arrhenatherum elatius)
Distribution: Introduced more commonly west of the Cascades, British Columbia south to California, east to Idaho and Montana.
Habitat: Meadows and pastures.
Origin: Introduced
Flowers: May - July
Timber oatgrass (Danthonia intermedia)
Origin: Native
Flowers: July - August
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
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
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
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
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-May
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
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
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
Autumn olive (Elaeagnus umbellata)
Distribution: Scattered localities in Washington; widely distributed east of the Mississippi River in the U.S.
Habitat: Introduced from eastern Asia as ornamental shrub, occasionally escaping in disturbed areas and waste ground.
Origin: Introduced
Flowers: June-July
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
Columbia onion (Allium columbianum)
Distribution: Occurring in easternmost Washington; east to Idaho and Montana.
Habitat: Seasonally wet soils on rock outcrops, wet meadows.
Origin: Native
Flowers: May-July
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
Douglas' onion (Allium douglasii)
Distribution: East of the Cascades in Washington; central and eastern Washington south to northeastern Oregon.
Habitat: Open, vernally-moist areas at low to moderate elevations.
Origin: Native
Flowers: May-July
Fragile onion (Allium scilloides)
Distribution: Douglas County to Klickitat County, Washington, lower foothills of the Cascades to east of the Columbia River
Habitat: Scablands and dry, barren, gravelly soils.
Origin: Native
Flowers: March - April
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
Geyer's onion (Allium geyeri)
Distribution: From the Cascades east in Washington and northern Idaho; disjunct in South Dakota, Utah and Texas.
Habitat: Low meadows and along streams.
Origin: Native
Flowers: May - June
Grand Coulee onion (Allium constrictum)
Distribution: Grant and Douglas Counties, Washington.
Habitat: Shallow, vernally-moist soils in low, open areas.
Origin: Native
Flowers: May - July
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
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
Nodding onion (Allium cernuum)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia south 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
Olympic onion (Allium crenulatum)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia south to Oregon.
Habitat: Forest openings and mountain meadows, moderate to high elevations.
Origin: Native
Flowers: May-July
Pacific onion (Allium validum)
Distribution: Occurring in the Olympic Mountains and West Cascades in Washington; southern British Columbia to California, east to Idaho and northern Nevada.
Origin: Native
Flowers: June - August
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
Rock onion (Allium macrum)
Distribution: In Washington, Kittitas and Douglas Counties south to Walla Walla and Klickitat Counties; more common in north-central Oregon.
Habitat: Lithosol and barren, gravelly soils in the shrub-steppe.
Origin: Native
Flowers: April - May
Rosy Sierra onion (Allium campanulatum)
Distribution: In the mountains in eastern Oregon, California dnd Nevada, and on Bethel Ridge, Yakima County, Washington.
Habitat: Dry soils at medium to high elevations.
Origin: Native
Flowers: June - July
Scalloped onion (Allium crenulatum)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia south to Oregon.
Habitat: Forest openings and mountain meadows, moderate to high elevations.
Origin: Native
Flowers: May-July
Scilla-like onion (Allium scilloides)
Distribution: Douglas County to Klickitat County, Washington, lower foothills of the Cascades to east of the Columbia River
Habitat: Scablands and dry, barren, gravelly soils.
Origin: Native
Flowers: March - April
Swamp onion (Allium validum)
Distribution: Occurring in the Olympic Mountains and West Cascades in Washington; southern British Columbia to California, east to Idaho and northern Nevada.
Origin: Native
Flowers: June - August
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
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
Tolmie's onion (Allium tolmiei)
Distribution: South-east Washington; eastern Oregon, western Idaho and north-east California.
Habitat: Rocky, gravelly or clayey soils, generally with sparse cover.
Origin: Native
Flowers: April-July
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
Alaska oniongrass (Melica subulata)
Distribution: Southern Alaska south to California, east to Montana and Wyoming.
Habitat: Open slopes to thick, dry or moist woods, from near sea level to mid-elevations in the mountains.
Origin: Native
Flowers: May - July
Ookow (Dichelostemma congestum)
Distribution: Scattered locations in Washington from the east side of the Olympic Peninsula and Island County to the Columbia River; Washington south to California.
Habitat: Grassy meadows, rocky prairies and sagebrush slopes.
Origin: Native
Flowers: May-June
Orach (Atriplex heterosperma)
Distribution: Primarily east of the Cascades crest in Washington; occurring in scattered locations throughout North America.
Habitat: Riparian zones and adjacent fields; tolerant of alkaline.
Origin: Introduced from Eurasia
Flowers: June-August
Red orach (Atriplex rosea)
Distribution: Occurring east of the Cascades crest in Washington; British Columbia south to California, east to the Rocky Mountains; scattered locations in central and eastern U.S.
Habitat: Weedy species of irrigated land and roadsides.
Origin: Introduced from Eurasia
Flowers: July-September
Russian atriplex orach (Atriplex heterosperma)
Distribution: Primarily east of the Cascades crest in Washington; occurring in scattered locations throughout North America.
Habitat: Riparian zones and adjacent fields; tolerant of alkaline.
Origin: Introduced from Eurasia
Flowers: June-August
Tumbling orach (Atriplex rosea)
Distribution: Occurring east of the Cascades crest in Washington; British Columbia south to California, east to the Rocky Mountains; scattered locations in central and eastern U.S.
Habitat: Weedy species of irrigated land and roadsides.
Origin: Introduced from Eurasia
Flowers: July-September
Garden orache (Atriplex hortensis)
Distribution: Occurring east of the Cascades crest in Washington; Alaska south 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
Gmelin's orache (Atriplex gmelinii)
Distribution: Occurring along the coast in Washington; Alaska south to California.
Habitat: On coastal beaches, strands, and rocky outcroppings near the high tide in saline soil.
Origin: Native
Flowers: June-September
Grassleaf orache (Atriplex littoralis)
Origin: Introduced from Europe
Flowers: June - September
Halberdleaf orache (Atriplex patula)
Distribution: Occurring on both sides of the Cascades crest in Washington; occurring in scattered locations throughout North America.
Habitat: Coastal and inland, saline or alkaline soil.
Origin: Introduced from Eurasia
Flowers: June-September
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
Long-stalked orache (Atriplex longipes)
Origin: Introduced
Narrow-leaved orache (Atriplex littoralis)
Origin: Introduced from Europe
Flowers: June - September
Oblongleaf orache (Atriplex oblongifolia)
Origin: Introduced from Europe
Silver orache (Atriplex argentea)
Origin: Native
Flowers: July - September
Silverscale orache (Atriplex argentea)
Origin: Native
Flowers: July - September
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
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
Wedge orache (Atriplex truncata)
Origin: Native
Flowers: June - August
Wedgeleaf orache (Atriplex truncata)
Origin: Native
Flowers: June - August
Wedgescale orache (Atriplex truncata)
Origin: Native
Flowers: June - August
Spear oracle (Atriplex patula)
Distribution: Occurring on both sides of the Cascades crest in Washington; occurring in scattered locations throughout North America.
Habitat: Coastal and inland, saline or alkaline soil.
Origin: Introduced from Eurasia
Flowers: June-September
Alaska rein orchid (Platanthera unalascensis)
Distribution: Widely distributed throughout Washington; Alaska south to California, east to Quebec and Colorado.
Habitat: Dry, open woods and gravelly streambanks, low to mid-elevations in the mountains.
Origin: Native
Flowers: June-August
Boreal bog orchid (Platanthera dilatata)
Distribution: Widely distributed through the mountainous and forested areas of Washington; Alaska south to California, east to the Rocky Mountains; also in northeastern in North America.
Habitat: Wet meadows, forest openings, and streambanks from low elevations to the subalpine.
Origin: Native
Flowers: June-September
Canyon bog orchid (Platanthera sparsiflora)
Origin: Native
Canyon bog orchid (Platanthera stricta)
Distribution: Widely distributed throughout Washington; Alaska south to California, east to Montana and New Mexico.
Habitat: Wet meadows, swamps and coniferous forests, low to mid-elevations.
Origin: Native
Flowers: June-August
Choriso bog orchid (Platanthera chorisiana)
Distribution: Known only from Snohomish County in Washington; Aleutian Islands south the 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
Dense orchid (Platanthera elongata)
Distribution: Occurring on both sides of the Cascades in Washington; British Columbia south to California, east to Idaho and Montana.
Habitat: Dry, open forest from low to middle elevations.
Origin: Native
Flowers: July-September
Dense-flower rein orchid (Platanthera elongata)
Distribution: Occurring on both sides of the Cascades in Washington; British Columbia south to California, east to Idaho and Montana.
Habitat: Dry, open forest from low to middle elevations.
Origin: Native
Flowers: July-September
Eagle rein orchid (Platanthera aquilonis)
Distribution: Known only from Steven County in Washington; Alaska south to Oregon, east across the northern half of North America to the Atlantic Coast;
Habitat: Wet meadows from montane to subalpine.
Origin: Native
Flowers: June-August
Fen orchid (Liparis loeselii)
Distribution: Occasional, Saskatchewan to Nova Scotia, south to North Dakota and Iowa; Klickitat and Yakima Counties in Washington.
Habitat: Around springs and in bogs.
Origin: Native
Flowers: July - August
Large round-leaf orchid (Platanthera orbiculata)
Distribution: Alaska to Newfoundland, south on both sides of the Cascades to Oregon, Idaho and northwest Montana; east to Minnisota, Indiana and Georgia.
Habitat: Moist, mossy forests.
Origin: Native
Flowers: June - August
Long-bracted orchid (Dactylorhiza viridis)
Distribution: Known only from Okanogan County in Washington; Alaska south to Washington, east across the southern half of Canada to the Atlantic Coast; south in the Rocky Mountains to New Mexico; east from the upper Midwest to the northeastern U.S., south in the Appalachian Mts.
Habitat: Moist to wet meadows at moderate elevations.
Origin: Native
Flowers: July-August
Needle-spur green orchid (Platanthera stricta)
Distribution: Widely distributed throughout Washington; Alaska south to California, east to Montana and New Mexico.
Habitat: Wet meadows, swamps and coniferous forests, low to mid-elevations.
Origin: Native
Flowers: June-August
Northern green bog orchid (Platanthera huronensis)
Distribution: Occurring chiefly east of the Cascades crest in Washington; Alaska south to Oregon, east to the Rocky Mountains; also from north-central to northeastern North America.
Habitat: Moist to boggy areas, often on limestone, low to mid-elevations.
Origin: Native
Flowers: June-August
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
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
Sheviak's bog orchid (Platanthera aquilonis)
Distribution: Known only from Steven County in Washington; Alaska south to Oregon, east across the northern half of North America to the Atlantic Coast;
Habitat: Wet meadows from montane to subalpine.
Origin: Native
Flowers: June-August
Slender bog orchid (Platanthera stricta)
Distribution: Widely distributed throughout Washington; Alaska south to California, east to Montana and New Mexico.
Habitat: Wet meadows, swamps and coniferous forests, low to mid-elevations.
Origin: Native
Flowers: June-August
White orchid (Platanthera dilatata)
Distribution: Widely distributed through the mountainous and forested areas of Washington; Alaska south to California, east to the Rocky Mountains; also in northeastern in North America.
Habitat: Wet meadows, forest openings, and streambanks from low elevations to the subalpine.
Origin: Native
Flowers: June-September
White rein orchid (Platanthera dilatata)
Distribution: Widely distributed through the mountainous and forested areas of Washington; Alaska south to California, east to the Rocky Mountains; also in northeastern in North America.
Habitat: Wet meadows, forest openings, and streambanks from low elevations to the subalpine.
Origin: Native
Flowers: June-September
White-lip rein orchid (Platanthera ephemerantha)
Distribution: West of the Cascades in Washington and Columbia River Gorge; Alaska to California.
Habitat: Moist coniferous forest at low elevations.
Origin: Native
Flowers: May-June
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
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
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
Holly-leaf Oregon-grape (Mahonia aquifolium)
Distribution: Widely distributed throughout 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
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
Shining Oregon-grape (Mahonia aquifolium)
Distribution: Widely distributed throughout 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
Tall Oregon-grape (Mahonia aquifolium)
Distribution: Widely distributed throughout 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
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
Cockscomb oreocarya (Oreocarya glomerata)
Distribution: Chiefly east of the Cascades, from southern British Colombia to Grant County, Oregon, east to North Dakota.
Habitat: Dry, open places in the valleys, plains and foothills, occasionally higher.
Origin: Native
Flowers: April - July
Sheldon's oreocarya (Oreocarya glomerata)
Distribution: Chiefly east of the Cascades, from southern British Colombia to Grant County, Oregon, east to North Dakota.
Habitat: Dry, open places in the valleys, plains and foothills, occasionally higher.
Origin: Native
Flowers: April - July
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
Purple osier (Salix purpurea)
Origin: Introduced
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
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
Ovalpurse (Hornungia procumbens)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia south to California, east to the Rocky Mountains, central Canada, and Newfoundland.
Habitat: Open areas where seasonally moist.
Origin: Native?
Flowers: March-June
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
Golden-tongue owl-clover (Orthocarpus luteus)
Distribution: East of the Cascades in Washington; British Columbia south to California, east to Manitoba and Nebraska.
Habitat: Low ground, from the plains to moderate elevations in the mountains.
Origin: Native
Flowers: June-August
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
Johnny-tuck owl-clover (Triphysaria eriantha)
Origin: Introduced as waif and/or cultivar from CA; occurrence based on records from late 1800s; no recent records or evidence of establishment in WA
Mountain owl-clover (Orthocarpus imbricatus)
Distribution: Olympic Mountains and Cascades of Washington; British Columbia south to Oregon and California.
Habitat: Fairly dry meadows and rocky slopes, mid- to high elevations in the mountains.
Origin: Native
Flowers: July-September
Narrow-leaved owl-clover (Orthocarpus tenuifolius)
Distribution: East of the Cascade 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
Paint-brush owl-clover (Castilleja ambigua)
Distribution: Coastal areas, Washington to California
Habitat: Salt marshes and borders of brackish ponds
Origin: Native
Flowers: June-September
Rosy owl-clover (Orthocarpus bracteosus)
Distribution: In Washington from the east base of the Cascades westward; southern British Columbia south to northern California.
Habitat: Meadows at low elevations.
Origin: Native
Flowers: June-August
Thin-leaved owl-clover (Orthocarpus tenuifolius)
Distribution: East of the Cascade 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
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