Western wake-robin (Trillium ovatum)
Distribution: Widely distributed on both sides of the Cascades crest in forested areas in Washington; British Columbia to California, east to Montana, Wyoming, and Colorado.
Habitat: Open to dense moist forests at low to mid-elevations, often where boggy in the spring.
Origin: Native
Flowers: March-June
Growth Duration: Perennial

Slimleaf wall rocket (Diplotaxis tenuifolia)
Origin: Introduced

Pale wallflower (Erysimum occidentale)
Distribution: Occurring east of the Cascades crest in Washington; Washington north-central and northeastern Oregon.
Habitat: Sagebrush hills and valleys.
Origin: Native
Flowers: March-May
Growth Duration: Biennial, Perennial

Sand-dwelling wallflower (Erysimum arenicola)
Distribution: Occurring chiefly in the mountainous areas of Washington; British Columbia to Oregon.
Habitat: Open ridges and rock crevices, moderate to high elevations in the mountains.
Origin: Native
Flowers: June-September
Growth Duration: Perennial

Wallflower (Erysimum cheiri)
Distribution: Occurring west of the Cascades crest in Washington; Yukon Territory to California, and in scattered locations in eastern North America.
Habitat: Disturbed areas, often escaped from cultivation.
Origin: Introduced
Flowers: April-June
Growth Duration: Perennial

Wormseed wallflower (Erysimum cheiranthoides)
Distribution: Occurring chiefly east of the Cascades crest in Washington; widely distributed throughout much of North America.
Habitat: Disturbed areas including fields, roadsides and wastelots, often where moist.
Origin: Introduced from Eurasia
Flowers: June-August
Growth Duration: Annual

English walnut (Juglans regia)
Origin: Introduced from Europe
Growth Duration: Perennial

Northern California walnut (Juglans hindsii)
Origin: Introduced

Wapato (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

Lesser wartcress (Lepidium didymum)
Distribution: Occurring west of the Cascades crest in Washington; British Columbia to California, Arizona, and Texas eastward and northward to the Atlantic Coast.
Habitat: Roadsides, gardens and wasteland.
Origin: Introduced from South America (or possibly Eurasia)
Flowers: May-July
Growth Duration: Annual, Biennial

Wartweed (Euphorbia helioscopia)
Distribution: Introduced chiefly west of the Cascades in Washington; widely distributed throughout much of North America.
Habitat: Weed of cultivated areas and abondoned gardens.
Origin: Introduced from Eurasia
Flowers: April-July
Growth Duration: Annual

European water plantain (Alisma plantago-aquatica)
Distribution: Currently only known from King County in Washington; Alaska, where native, to British Columbia, where also introduced.
Habitat: Marshy areas, sometimes largely submerged.
Origin: Introduced from Eurasia and Alaska
Flowers: June-September
Growth Duration: Perennial

Northern water plantain (Alisma triviale)
Distribution: Widely distributed on both sides of the Cascades crest in Washington; Alaska to California, east across much of North America to the Atlantic Coast.
Habitat: Streams, lakes, ponds, wet ditches, wetlands, and cattle ponds.
Origin: Native
Flowers: June-September
Growth Duration: Perennial

Water purslane (Ludwigia palustris)
Distribution: Occurring west of the Cascades crest and along the Columbia River in Washington; southern British Columbia to California, east to Idaho, east across the southwestern U.S. and southern Great Plains to eastern North America; also occurring in New World Tropics and Eurasia.
Habitat: Lakes, marshes, peatlands, shores, and wet meadows.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Water-clover (Marsilea oligospora)
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to Montana, Wyoming, and Utah.
Habitat: Ponds and marshes, in wet depressions in sagebrush and less commonly on river margins.
Origin: Native
Spores: June-October
Growth Duration: Perennial

Bulblet-bearing water-hemlock (Cicuta bulbifera)
Distribution: Occurring in scattered locations on both sides of the Cascades crest in Washington; British Columbia to southern Oregon, east to Newfoundland and Virginia,
Habitat: Marshes, bogs, wet meadows and standing water, lowlands to mountain valleys.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Douglas' water-hemlock (Cicuta douglasii)
Distribution: Widely distributed on both sides of the Cascades crest in Washington; Alaska to Oregon, east to Alberta, Montana and Wyoming.
Habitat: Marshes, ditches, and wet low places, from low to middle elevations in the mountains.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Western water-hemlock (Cicuta douglasii)
Distribution: Widely distributed on both sides of the Cascades crest in Washington; Alaska to Oregon, east to Alberta, Montana and Wyoming.
Habitat: Marshes, ditches, and wet low places, from low to middle elevations in the mountains.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

European water-horehound (Lycopus europaeus)
Origin: Introduced from Europe

Disk water-hyssop (Bacopa rotundifolia)
Distribution: Occurring east of the Cascades crest in south-central Washington; south-central Washington to California (but not in Oregon), east to the Rocky Mountains, native to central and eastern North America.
Habitat: Mudfalts, mud-bottomed pools, backchannels, and other slow-moving water of streams and rivers.
Origin: Introduced from central North America
Flowers: July-September
Growth Duration: Perennial

American water-lily (Nymphaea odorata)
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia to California, east to central and eastern North America, where native.
Habitat: Lowland ponds and lakes.
Origin: Introduced from central and eastern North America
Flowers: June-October
Growth Duration: Perennial

Pygmy water-lily (Nymphaea tetragona)
Origin: Native
Flowers: June - August
Growth Duration: Perennial

Various-leaved water-milfoil (Myriophyllum heterophyllum)
Distribution: Known only from Puget Sound lowlands in Washington; British Columbia south to California; widely distributed east of the Mississippi River in Canada and the U.S where apparently it is native.
Habitat: Lakes and ponds.
Origin: Introduced
Flowers: May-October
Growth Duration: Perennial

Guadalupe water-nymph (Najas guadalupensis)
Distribution: Occurring west of the Cascades crest in Washington; Washington to Baja California, east to the Atlantic Coast.
Habitat: Fresh water habitats.
Origin: Native
Flowers: June-August
Growth Duration: Annual

Slender water-nymph (Najas flexilis)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to Montana, Colorado, Utah, and Arizona, east across the northern Great Plains to the Great Lakes region and eastern North America.
Habitat: Fresh to slightly brackish water.
Origin: Native
Flowers: April-August
Growth Duration: Annual

Pacific water-parsley (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

Mild water-pepper (Persicaria hydropiper)
Distribution: Introduced weed found in much of North America and throughout the Pacific Northwest.
Habitat: Swamps, ditches, and other wet places, mostly at low elevations.
Origin: Introduced
Flowers: July - September

Narrow-leaf water-plantain (Alisma gramineum)
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east to Minnesota and Wisconsin.
Habitat: Marshy areas, often in standing water.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Different-leaved water-starwort (Callitriche heterophylla)
Distribution: North and South America and Greenland.
Habitat: Sloughs and slow-moving, fresh water.
Origin: Native
Flowers: April - July
Growth Duration: Annual, Perennial

Northern water-starwort (Callitriche hermaphroditica)
Distribution: Across northern North America, south to central California, northern New Mexico, the Great Lakes, and northeast United States.
Habitat: Sloughs and streams.
Origin: Native
Flowers: July - September
Growth Duration: Perennial

Spring water-starwort (Callitriche palustris)
Distribution: General in North America except Mexico and south and southeast United States.
Habitat: Sloughs and slow-moving fresh water.
Origin: Native
Flowers: June - August
Growth Duration: Perennial

Winged water-starwort (Callitriche marginata)
Distribution: Reported from eastern counties in Washington; British Columbia south to California.
Habitat: Ponds, lakes, slow-moving streams.
Origin: Native
Flowers: July-August
Growth Duration: Perennial

Pacific watercarpet (Chrysosplenium glechomifolium)
Distribution: Occurring west of the Cascades crest in Washington; British Columbia to northwest California.
Habitat: Moist, usually swampy places, mostly at low elevations.
Origin: Native
Flowers: March-May
Growth Duration: Perennial

Onerow watercress (Nasturtium microphyllum)
Distribution: Occurring west of the Cascades crest in Washington; British Columbia to Oregon, east to Idaho, Montana, and Wyoming; also in the northeastern U.S.
Habitat: Shallow water, ditches, and marshy areas.
Origin: Introduced from Europe
Flowers: May-July
Growth Duration: Annual

Ballhead waterleaf (Hydrophyllum capitatum)
Distribution: Occurring mostly east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Moist, open slopes and woodlands, foothills to middle elevations in the mountains.
Origin: Native
Flowers: March-July
Growth Duration: Perennial

Pacific waterleaf (Hydrophyllum tenuipes)
Distribution: Occurring west of the Cascades crest in Washington; southwestern British Columbia to California.
Habitat: Forest understory and edge at low elevations, often where moist.
Origin: Native
Flowers: May-July
Growth Duration: Perennial

Columbian watermeal (Wolffia columbiana)
Distribution: Occurring chiefly west of the Cascades crest in Washington; Washington to California, east to Alberta, Idaho, Montana, and Colorado, and east from the Great Plains to the Atlantic Coast.
Habitat: Ponds and standing water at low elevations.
Origin: Native
Growth Duration: Perennial

Watermelon (Citrullus lanatus)
Origin: Introduced

Brazilian waterweed (Egeria densa)
Distribution: Occurring chiefly west of the Cascades crest in Washington; southwestern British Columbia to California, east across the southern half of the United States to the Atlantic.
Habitat: Ponds, lakes, and slow-moving water at low elevation.
Origin: Introduced from South America
Flowers: July-September
Growth Duration: Perennial

Common waterweed (Elodea canadensis)
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: Common in ponds, lakes, streams, rivers, and slow-moving waters.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Rocky Mountain waterweed (Elodea canadensis)
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: Common in ponds, lakes, streams, rivers, and slow-moving waters.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Waterweed (Egeria densa)
Distribution: Occurring chiefly west of the Cascades crest in Washington; southwestern British Columbia to California, east across the southern half of the United States to the Atlantic.
Habitat: Ponds, lakes, and slow-moving water at low elevation.
Origin: Introduced from South America
Flowers: July-September
Growth Duration: Perennial

California waterwort (Elatine californica)
Origin: Native
Growth Duration: Annual

Pacific wax-myrtle (Morella californica)
Distribution: Occurring west of the Cascades crest along the outer coast in Washington; coastal Vancouver Island, British Columbia to California.
Habitat: Hillsides and sandy areas near the coast.
Origin: Native
Flowers: April-May
Growth Duration: Perennial

Prairie wedgescale (Sphenopholis obtusata)
Origin: Native
Flowers: June - July
Growth Duration: Annual, Perennial

Jimson weed (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

Pahute weed (Suaeda calceoliformis)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Great Plains, and also along the coast of eastern North America.
Habitat: Open, moist to wet areas, typically where saline.
Origin: Native
Flowers: June-August
Growth Duration: Annual

Poverty weed (Iva axillaris)
Distribution: Occurring east of the Cascades crest in Washington; southern British Columbia to California, east to the Rocky Mountains, Great Plains, and Great Lakes region.
Habitat: Dry, often alkaline places, in the valleys, plains and foothills.
Origin: Native
Flowers: May-September
Growth Duration: Perennial

Rattlesnake weed (Daucus pusillus)
Distribution: Occurring west of the Cascades crest and east in the Columbia River Gorge in Washington; southwestern British Columbia to California, east across the southern U.S. to the Atlantic Coast.
Habitat: Grassy balds, headlands, rocky outcroppings, and other to seasonally moist open areas at low elevations.
Origin: Native
Flowers: May-July
Growth Duration: Annual

Weld (Reseda luteola)
Distribution: Occurring in scattered locations on both sides of the Cascades crest in Washington; British Columbia to California; scattered locations in central and eastern North America.
Habitat: Disturbed ground at low elevations.
Origin: Introduced from Europe
Flowers: May-September
Growth Duration: Biennial

Narrow-leaved cow wheat (Melampyrum lineare)
Distribution: Occurring in the northeastern corner of Washington; British Columbia south to Washington, east across the northern half of North America to the Atlantic Coast.
Habitat: Forest openings, rocky outcroppings, and wet areas from low to moderate elevations.
Origin: Native
Flowers: July-August
Growth Duration: Annual

Annual false wheatgrass (Eremopyrum triticeum)
Distribution: Occurring in scattered locations east of the Cascades crest in Washington; British Columbia to Arizona, east to the Rocky Mountains and Great Plains.
Habitat: Dry wasteland, disturbed areas.
Origin: Introduced
Flowers: May-July
Growth Duration: Annual

Bearded wheatgrass (Elymus violaceus)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to Oregon, east to the Rocky Mountains, east across Canada to the Atlantic Coast.
Habitat: High montane to alpine rocks and grassland.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Crested wheatgrass (Agropyron cristatum)
Distribution: Occurring east of the Cascades crest in Washington; Alaska to California, east across much of North America to the Atlantic Coast.
Habitat: Dry, open areas where distiurbed; frequently planted for soil stabilization and forage.
Origin: Introduced from Eurasia
Flowers: June-August
Growth Duration: Perennial

Intermediate wheatgrass (Thinopyrum intermedium)
Origin: Introduced
Flowers: June - August
Growth Duration: Perennial

Slender wheatgrass (Elymus trachycaulus)
Origin: Native
Growth Duration: Perennial

Common whipplea (Whipplea modesta)
Distribution: Occurring on the Olympic Peninsula in Washington; Washington to California.
Habitat: Dry, rocky, open to lightly forested areas.
Origin: Native
Flowers: April-June
Growth Duration: Perennial

Asian white-top (Lepidium chalepense)
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Great Lakes region.
Habitat: Disturbed areas, especially where dry, often associated with agriculture.
Origin: Introduced from Asia
Flowers: May-June
Growth Duration: Perennial

Alaska whitlow-grass (Draba stenoloba)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to Oregon, east to Alberta.
Habitat: Sublapine meadows to alpine slopes.
Origin: Native
Flowers: May-August
Growth Duration: Annual, Biennial, Perennial

Alpine whitlow-grass (Draba aureola)
Distribution: Occurring west of the Cascades crest in Washington in the Mount Rainier area; Washington to northern California
Habitat: Alpine areas, including scree and moraine areas.
Origin: Native
Flowers: June-August
Growth Duration: Biennial, Perennial

Carolina whitlow-grass (Draba reptans)
Distribution: Occurring east of the Cascades crest in Washington; central British Columbia to California, east to the Atlantic Coast.
Habitat: Desert plains and foothills.
Origin: Native
Flowers: March-May
Growth Duration: Annual

Dense-leaf whitlow-grass (Draba densifolia)
Distribution: Occurring east of the Cascades crest in Washington; Alaska to California, east to Alberta, Idaho, Wyoming, Nevada and Utah.
Habitat: Open, rocky places from mid- to high elevations in the mountains.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Few-seeded whitlow-grass (Draba oligosperma)
Distribution: Occurring chiefly east of the Cascades crest in Washington; Alaska to California, east to Colorado.
Habitat: From sagebrush plains to alpine slopes.
Origin: Native
Flowers: May-August
Growth Duration: Perennial

Great alpine whitlow-grass (Draba aureola)
Distribution: Occurring west of the Cascades crest in Washington in the Mount Rainier area; Washington to northern California
Habitat: Alpine areas, including scree and moraine areas.
Origin: Native
Flowers: June-August
Growth Duration: Biennial, Perennial

Payson's whitlow-grass (Draba novolympica)
Distribution: Occurring in the Olympics and Cascades mountains of Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Open slopes, talus ridges, and other exposed areas in the alpine.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Snowbed whitlow-grass (Draba crassifolia)
Distribution: Occurring in the Olympic Mountains and North Cascades in Washington; Alaska to Washington, Nevada, east to the Rocky Mountains; east across northern Canada to Greenland; northern Europe.
Habitat: Subalpine and alpine meadows, often in rock crevices and outcroppings.
Origin: Native
Flowers: June-August
Growth Duration: Annual, Perennial

Tall whitlow-grass (Draba praealta)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, e to Northwest Territories, Alberta Montana, Idaho, Wyoming, and central Nevada.
Habitat: Montane woodland to subalpine ridges.
Origin: Native
Flowers: June-August
Growth Duration: Biennial, Perennial

Whitlow-wort (Draba incerta)
Distribution: Occurring in the Cascades and Olympic Mountains in Washington; British Columbia and Alberta south to Washington, east to Montana and Wyoming.
Habitat: Alpine and subalpine slopes.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Yellowstone draba whitlow-wort (Draba incerta)
Distribution: Occurring in the Cascades and Olympic Mountains in Washington; British Columbia and Alberta south to Washington, east to Montana and Wyoming.
Habitat: Alpine and subalpine slopes.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Blue wild-rye (Elymus glaucus)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Great Plains and Great Lakes region.
Habitat: Prairies, open woods, and dry to moist hillsides, from the lowlands to middle elevations in the mountains.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Beardless wildrye (Leymus triticoides)
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and Texas.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Creeping wildrye (Elymus repens)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast; circumboreal.
Habitat: Fields, roadsides, meadows, pastures, wastelots, and other disturbed open areas.
Origin: Introduced from Eurasia
Flowers: June-August
Growth Duration: Perennial

Mammoth wildrye (Leymus racemosus)
Distribution: Occurring east of the Cascades crest in Washington; central Washington to north-central Oregon, east to Wyoming.
Habitat: Sandy areas in sagebrush flats and plains.
Origin: Introduced from Eurasia
Flowers: July-August
Growth Duration: Perennial

Scribner's wildrye (Elymus scribneri)
Distribution: Occurring in the Cascades Range in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Open, rocky, often windswept subalpine and alpine regions.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Sweet William (Dianthus barbatus)
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia to California, east to Idaho and Montana, also from the Great Plains east to the Atlantic Coast.
Habitat: Fields, roadsides, wastelots, and other disturbed areas.
Origin: Introduced from Europe
Flowers: June-August
Growth Duration: Perennial

Arctic willow (Salix arctica)
Distribution: Occurring in northwestern Washington; Alaska to northwestern Washington, east across northern Canada; circumboreal.
Habitat: In wet to dry areas in the alpine.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Barclay's willow (Salix barclayi)
Distribution: Chiefly in the Olympic and Cascade mountains of Washington; Alaska east to Northwest Territories, south to Oregon and Wyoming.
Habitat: Lakes, streams, and other riparian areas in subalpine and alpine zone.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Bebb's willow (Salix bebbiana)
Distribution: Chiefly east of the Cascades in Washington; widely distributed throughout North America except for southcentral and southeastern U.S.
Habitat: Lakes, streams, and other riparian areas from low to moderate elevations in the mountains.
Origin: Native
Flowers: April-June
Growth Duration: Perennial

Booth's willow (Salix boothii)
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and Sasketchewan.
Habitat: Wet subalpine meadows, streambanks, lakeshores, and other riparian areas.
Origin: Native
Flowers: May-July
Growth Duration: Perennial

Coastal willow (Salix hookeriana)
Distribution: Chiefly west of the Cascades in Washington; British Columbia south to California.
Habitat: Moist, often swamps areas, from the sea coast to mid-elevations in the mountains.
Origin: Native
Flowers: March-April
Growth Duration: Perennial

Coyote willow (Salix exigua)
Distribution: Chiefly east of the Cascades in Washington; British Columbia and Alberta south to California, east through the Rocky Mountains to Nebraska and Texas.
Habitat: Riparian areas, gravel bars, lake and pond shore margins
Origin: Native
Flowers: April-May
Growth Duration: Perennial

Drummond's willow (Salix drummondiana)
Distribution: In the East Cascades and mountains of eastern Washington; Yukon Territory east to Northwest Territories, south to California, east through the Rocky Mountains.
Habitat: Streambanks, lakeshores, floodplains, and other riparian areas in montane and subalpine habitats.
Origin: Native
Flowers: April-June
Growth Duration: Perennial

Dwarf snow willow (Salix nivalis)
Distribution: In the Olympic and Cascade mountains of Washington; British Columbia and Alberta, south to California, east to Colorado.
Habitat: Subalpine meadows and alpine areas.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Farr's willow (Salix farriae)
Distribution: Occurring east of the Cascades crest in Washington, where known only from Okanogan County; Yukon to northern Washington and northeast Oregon, east to Montana, Idaho and Wyoming.
Habitat: Wet meadows and riparian zones from montane areas to the subalpine.
Origin: Native
Flowers: June-July
Growth Duration: Perennial

Gray willow (Salix bebbiana)
Distribution: Chiefly east of the Cascades in Washington; widely distributed throughout North America except for southcentral and southeastern U.S.
Habitat: Lakes, streams, and other riparian areas from low to moderate elevations in the mountains.
Origin: Native
Flowers: April-June
Growth Duration: Perennial

Long-beak willow (Salix bebbiana)
Distribution: Chiefly east of the Cascades in Washington; widely distributed throughout North America except for southcentral and southeastern U.S.
Habitat: Lakes, streams, and other riparian areas from low to moderate elevations in the mountains.
Origin: Native
Flowers: April-June
Growth Duration: Perennial

Mackenzie's willow (Salix prolixa)
Distribution: Widely distributed throughout Washington; British Columbia to California, east to Newfoundland and Virginia.
Habitat: Along streams in the lowlands to lower valleys in the mountains.
Origin: Native
Flowers: April-June
Growth Duration: Perennial

One-color willow (Salix monochroma)
Origin: Native
Growth Duration: Perennial

Peach-leaf willow (Salix amygdaloides)
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to Oregon and Nevada, east to the Great Plains, upper midwest, and eastern North America.
Habitat: Wetlands, streambanks, and other riparian areas.
Origin: Native
Flowers: March-May
Growth Duration: Perennial

Purple willow (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.
Origin: Introduced

Sage willow (Salix candida)
Distribution: In the mountains of northeastern and southeastern Washington; widespread across North America from Alaska south to Washington, east through central U.S. to Canadian Maritimes.
Habitat: Lakeshores, pond margins, streambanks, and other riparian areas.
Origin: Native
Flowers: April-June
Growth Duration: Perennial

Scouler's willow (Salix scouleriana)
Distribution: Widely distributed on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains and northern Great Plains.
Habitat: Moist woods and streambanks, lowlands to moderate elevations in the mountains.
Origin: Native
Flowers: March-June
Growth Duration: Perennial

Short-fruited willow (Salix brachycarpa)
Distribution: Occurring east of the Cascades crest in Washington; Yukon Territory to California, east to the Rocky Mountains, and east across Canada to Quebec.
Habitat: Riparian areas, wetlands, and meadows from middle elevations to the subalpine.
Origin: Native
Flowers: April-June
Growth Duration: Perennial

Sitka willow (Salix sitchensis)
Distribution: Occurring in forested areas on both sides of the Cascades crest in Washington; Alaska to California, east to western Montana.
Habitat: Moist woods and stream banks, lowlands to moderate elevations in the mountains.
Origin: Native
Flowers: April-June
Growth Duration: Perennial

Tweedy's willow (Salix tweedyi)
Distribution: Chiefly North Cascade Mountains in Washington; British Columbia south to Washington, east to Montana, Idaho and Wyoming.
Habitat: Wet meadows, lake margins, streambanks, and other riparian areas in alpine and subalpine.
Origin: Native
Flowers: July-August
Growth Duration: Perennial

Variable willow (Salix commutata)
Distribution: Chiefly in the Olympic and Cascade mountains of Washington; Alaska and Yukon south to Oregon, occasionally east to idaho and Montana.
Habitat: Moist areas, mid- to high elevations in the mountains.
Origin: Native
Flowers: June-September
Growth Duration: Perennial

Willow weed (Persicaria lapathifolia)
Distribution: Widely distributed throughout Washington; widely distributed throughout all of North America.
Habitat: Streambanks, pond and lakeshores and other wet places.
Origin: Native
Flowers: May-September
Growth Duration: Perennial

Broad-leaved willow-herb (Epilobium montanum)
Origin: Introduced

Brook willow-herb (Epilobium torreyi)
Distribution: Occurring east of the Cascades crest in Washingtpn; southwestern British Columbia to California, east to Idaho and Nevada.
Habitat: Places that are soggy with standing water in winter and spring, drying in summer.
Origin: Native
Flowers: June-July
Growth Duration: Annual

Chaparral willow-herb (Epilobium minutum)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Alberta, Montana, Utah, and Arizona.
Habitat: Dry or gravelly soil, sea level to mid-elevations in the mountains.
Origin: Native
Flowers: April-August
Growth Duration: Annual

Marsh willow-herb (Epilobium palustre)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska east to California, east to the Rocky Mountains, Great Lakes region, and the Atlantic coast;.
Habitat: Wet soil, often in bogs.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Oregon willow-herb (Epilobium oregonense)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Montana, Wyoming, and Arizona.
Habitat: Streambanks, bogs, and wet meadows from moderate elevations in mountains to alpine.
Origin: Native
Flowers: June-September
Growth Duration: Perennial

Small-flowered willow-herb (Epilobium minutum)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Alberta, Montana, Utah, and Arizona.
Habitat: Dry or gravelly soil, sea level to mid-elevations in the mountains.
Origin: Native
Flowers: April-August
Growth Duration: Annual

Yellow willow-herb (Epilobium luteum)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to Alberta.
Habitat: Stream banks and wet areas at mid- to high elevations in the mountains.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Bog willowherb (Epilobium leptophyllum)
Origin: Introduced
Growth Duration: Perennial

Ciliate willowherb (Epilobium glandulosum)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains, also across southern Canada and the northern U.S. to the Atlantic Coast.
Habitat: Moist meadows and riparian areas from coastal elevations to subalpine.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Glandular willowherb (Epilobium hallianum)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and northern Great Plains.
Habitat: Moist to wet areas from montane to alpine habitats.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Slender-fruit willowherb (Epilobium leptocarpum)
Distribution: Occurring in scattered locations on both sides of the Cascades crest in Washington; Alaska to Oregon, east to Alberta and Idaho.
Habitat: Damp rocky slopes and ledges, shores, and wet meadow margins.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Smooth willowherb (Epilobium glaberrimum)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Wet places at mid-elevations in the mountains.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Talus willowherb (Epilobium clavatum)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to Alberta, Montana and Colorado.
Habitat: Moist meadows and talus slopes in the mountains, subalpine.
Origin: Native
Flowers: June-September
Growth Duration: Perennial

Columbian windflower (Anemone deltoidea)
Distribution: Occurring chiefly west of the Cascades crest and east in the Columbia River Gorge in Washington; Washington to California.
Habitat: Dry to moist woodlands at low to middle elevations.
Origin: Native
Flowers: April-May
Growth Duration: Perennial

Lyall's windflower (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

Oregon windflower (Anemone oregana)
Distribution: Occurring in forested areas on both sides of the Cascades crest in Washington; Washington to northern California.
Habitat: Moist, open woods, low to mid-elevations in the mountains, also in marshes and bogs along the coast.
Origin: Native
Flowers: March-June
Growth Duration: Perennial

Wingscale (Atriplex canescens)
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to the Great Plains.
Habitat: Sand or gravel slopes and sagebrush flats, saline or not.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Early wintercress (Barbarea verna)
Distribution: Occurring west of the Cascades crest in Washington; Alaska to California, east to Idaho and Colorado; also in central and eastern U.S.
Habitat: Fields, roadsides, wastelots, and other disturbed sites.
Origin: Introduced from Eurasia
Flowers: April-July
Growth Duration: Biennial, Perennial

Alpine wintergreen (Gaultheria humifusa)
Distribution: In the Olympics and Cascades mountains of Washington; British Columbia south to northern California, east to the Rocky Mountains from Alberta to Colorado.
Habitat: Subalpine to alpine, usually where moist to wet.
Origin: Native
Flowers: July-August
Growth Duration: Perennial

Green-flower wintergreen (Pyrola chlorantha)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska south to California, east to the Rocky Mountains and across northern U.S. and Canada to the Atlantic Coast.
Habitat: Chiefly in coniferous forests at moderate to mid-elevations, usually where moist.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Lesser wintergreen (Pyrola minor)
Distribution: Occurring on both sides of the Cascades in Washington; Alaska south to California, east to the Rocky Mountains; east across Canada and northern U.S. to the Atlantic Coast.
Habitat: Uncommon, mostly in moist areas in coniferous woods, moderate to high elevations in the mountains.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Slender wintergreen (Gaultheria ovatifolia)
Distribution: Chiefly in the Olympics and Cascades mountains in Washington, but also in the northeastern part of the State; British Columbia south to California, east to Idaho and Montana.
Habitat: Forested areas from fairly dry Ponderosa pine to subalpine bogs.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

White wintergreen (Pyrola elliptica)
Origin: Native

Small wirelettuce (Stephanomeria exigua)
Distribution: Occurring east of the Cascades crest in Washington, where known from Douglas County; otherwise central Oregon to California, east to Idaho, Colorado, and Texas.
Habitat: Sandy, open sites, often in sagebrush.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

False wireweed (Rigiopappus leptocladus)
Distribution: Occurring east of the Cascades crest in south-central Washington; Washington to California, east to Idaho and Nevada.
Habitat: Dry, open areas at low elevations; sagebrush and grasslands area
Origin: Native
Flowers: April-June
Growth Duration: Annual

Chinese wolfberry (Lycium chinense)
Origin: Introduced

Wolfberry (Symphoricarpos occidentalis)
Distribution: Occurring east of the Cascades crest in Washington; British Columbia south to Utah, east to the Atlantic Coast.
Habitat: Prairies, forest margins, and bottomlands from low to mid-elevations.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Crested wood-fern (Dryopteris cristata)
Distribution: Occurring east of the Cascades crest in northeastern Washington; Alaska to Idaho, east across northern U.S. and Canada to eastern North America; also in Europe.
Habitat: Moist woods and thickets at middle elevations in the mountains.
Origin: Native
Growth Duration: Perennial

Spreading wood-fern (Dryopteris expansa)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to Alberta, Idaho, and Montana.
Habitat: Moist to wet woods and streambanks.
Origin: Native
Growth Duration: Perennial

Slender wood-reed (Cinna latifolia)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains, northern Great Plains, and eastern North America.
Habitat: Moist woods and meadows, sea level to subalpine.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Creeping yellow wood-sorrel (Oxalis corniculata)
Distribution: Scattered locations throughout Washington; distributed widely throughout North America.
Habitat: A weed of gardens, disturbed areas, and waste places.
Origin: Introduced from Europe
Flowers: May-October
Growth Duration: Perennial

Oregon wood-sorrel (Oxalis oregana)
Distribution: Olympic Mountains and west slope of the Cascades in Washington; British Columbia south to California.
Habitat: Moist woods, low to moderate elevations.
Origin: Native
Flowers: April-September
Growth Duration: Perennial

Trillium-leaf wood-sorrel (Oxalis trilliifolia)
Distribution: West slope of the Cascades in Washington; Washington south to northwest California.
Habitat: Meadows and moist woods in the coastal mountains and up to 6000 feet in the Cascades.
Origin: Native
Flowers: May-August
Growth Duration: Perennial

Western yellow wood-sorrel (Oxalis suksdorfii)
Distribution: Occurring west of the Cascades crest in Washington; southern Washington to northwest California.
Habitat: Low elevations, usually in moist, coastal woods but sometimes on rather dry, open slopes.
Origin: Native
Flowers: April-August
Growth Duration: Perennial

Bulbous woodland star (Lithophragma glabrum)
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and northern Great Plains.
Habitat: Grasslands and sagebrush desert to ponderosa pine and Douglas-fir forest openings.
Origin: Native
Flowers: April-June
Growth Duration: Perennial

Small-flower woodland star (Lithophragma parviflorum)
Distribution: Widely distributed on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and Great Plains.
Habitat: Prairies, balds, sagebrush desert, and forest openings, sea level to mid-elevations in the mountains.
Origin: Native
Flowers: April-June
Growth Duration: Perennial

Common woodrush (Luzula multiflora)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to Oregon, east to Alberta and western Montana; also in northeastern United States.
Habitat: Fields, meadows, open woods and clearings, at low to middle elevations in the mountains.
Origin: Native
Flowers: May-July
Growth Duration: Perennial

Field woodrush (Luzula campestris)
Distribution: Occurring west of the Cascades crest in Washington; southwestern British Columbia to western Washington; also in New England.
Habitat: Lowland lawns or dry, disturbed ground.
Origin: Introduced
Flowers: April-May
Growth Duration: Perennial

Large-anthered woodrush (Luzula macrantha)
Distribution: Occurring chiefly west of the Cascades crest and in the Columbia River Gorge in Washington; southwestern British Columbia to California.
Habitat: Balds, prairies, grasslands, and forest openings at low to moderate elevations.
Origin: Native
Flowers: April-June
Growth Duration: Perennial

Pacific woodrush (Luzula comosa)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Coastal to montane openings, rocky slopes, forests and shores.
Origin: Native
Flowers: April-July
Growth Duration: Perennial

Prairie woodrush (Luzula macrantha)
Distribution: Occurring chiefly west of the Cascades crest and in the Columbia River Gorge in Washington; southwestern British Columbia to California.
Habitat: Balds, prairies, grasslands, and forest openings at low to moderate elevations.
Origin: Native
Flowers: April-June
Growth Duration: Perennial

Smooth woodrush (Luzula hitchcockii)
Distribution: Occurring on both sides of the Cascades crest in Washington; southern British Columbia to Crater Lake and the Wallowa Mountains of Oregon, east to Alberta, Montana, and northwestern Wyoming.
Habitat: Montane forests to alpine slopes, ridges and meadows.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Spiked woodrush (Luzula spicata)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains, east across northern Canada to northeastern North America; also in Eurasia.
Habitat: Subalpine to alpine slopes, moraines, and stream banks.
Origin: Native
Flowers: June-August
Growth Duration: Perennial

Woodsia (Woodsia scopulina)
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains, Great Plains, and scattered areas in eastern North America.
Habitat: Rock crevices, ledges and talus slopes in the mountains, and in less arid parts of the lowlands.
Origin: Native
Growth Duration: Perennial

Dwarf woolly-marbles (Psilocarphus brevissimus)
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the northern Great Plains and Rocky Mountains.
Habitat: Dried beds of vernal pools.
Origin: Native
Flowers: May-July
Growth Duration: Annual

Slender woollyheads (Psilocarphus tenellus)
Distribution: Occurring on both sides of the Cascades crest in Washington; southwestern British Columbia to California, east to Idaho.
Habitat: Dry or seasonally moist barren or wooded slopes or flats, often on disturbed sites.
Origin: Native
Flowers: March-August
Growth Duration: Annual

Wilcox's woolstar (Eriastrum wilcoxii)
Distribution: Occurring east of the Cascades crest in central Washington; central Washington to southern California, east to southern Idaho and western Utah.
Habitat: Sagebrush desert in sandy or stony soil.
Origin: Native
Flowers: May-August
Growth Duration: Annual

Annual wormwood (Artemisia annua)
Distribution: Occurring in scattered locations east of the Cascades crest and in the Columbia River Gorge in Washington; Washington to California, east across most of North America to the Atlantic Coast.
Habitat: Roadsides, fields, ditches, wastelots, and other disturbed open places.
Origin: Introduced from Eurasia
Flowers: August-October
Growth Duration: Annual

Biennial wormwood (Artemisia biennis)
Distribution: Occurring on both sides of the Cascades crest and in the Columbia River Gorge in Washington; Alaska to California, east across most of North America to the Atlantic Coast, where considered introduced.
Habitat: Roadsides, fields, irrigation ditches, streambanks, and other disturbed open areas, especially in sandy soil.
Origin: Native
Flowers: August-October
Growth Duration: Annual, Biennial

Cascade wormwood (Artemisia tilesii)
Distribution: Occurring in the Olympic and Cascade Mountains of Washington; Alaska to Oregon, east to Montana, and east across Canada to Quebec.
Habitat: Open rocky or gravelly, wet or dry sites, from middle elevations to the alpine, descending to sea level northward.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Douglas's wormwood (Artemisia douglasiana)
Distribution: Occurring on both sides of the Cascades crest and in the Columbia River Gorge in Washington; Washington to California, east to Nevada.
Habitat: Mostly along stream banks and river bottoms.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Forked wormwood (Artemisia furcata)
Distribution: Occurring in the Cascades and Olympic Mountains of Washington; Alaska to Washington, east to Northwest Territories, Alberta, and Nunavut.
Habitat: Open, rocky ledges and talus slopes in the subalpine and alpine.
Origin: Native
Flowers: July-September
Growth Duration: Perennial

Michaux's wormwood (Artemisia michauxiana)
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Alberta and Wyoming.
Habitat: Rocky places in the mountains at rather high elevations.
Origin: Native
Flowers: May-August
Growth Duration: Perennial

Steller's wormwood (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

Square-stalked St. John's Wort (Hypericum tetrapterum)
Distribution: Introduced occasionally in western Washington.
Habitat: Damp wasteland.
Origin: Introduced
Flowers: July - September
Growth Duration: Perennial

Narrowleaf wyethia (Wyethia angustifolia)
Distribution: Occurring west of the Cascades crest in southwestern Washington, and east in the Columbia River Gorge; Washington to California.
Habitat: Meadows and moist, open hillsides at low elevations.
Origin: Native
Flowers: May-July
Growth Duration: Perennial