Vascular Plants

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Scientific names beginning with S:
Sabulina basalticabasalt sandwort, Olympic sandwort
Sabulina sororiaTwin Sisters sandwort
Sagina apetalaannual pearlwort
Distribution: Occurring in the lowlands west of the Cascades crest in Washington; British Columbia south to California; Kansas.
Habitat: Waste ground.
Sagina decumbens
Distribution: Chiefly west of the Cascades in Washington; British Columbia south to southern California.
Habitat: Moist soil at low elevations, but not typically coastal.
ssp. occidentalis – western pearlwort
Sagina maxima
Distribution: Occurring in counties along the coast in Washington; distinctly coastal, Alaska south to Monterey County, California.
Habitat: Moist sand or rocks.
ssp. crassicaulis – stick-stemmed pearlwort
Sagina procumbensbird-eye pearlwort
Distribution: Introduced west of the Cascades, British Columbia to California
Habitat: Moist areas, especially gardens
Sagina saginoidesalpine pearlwort
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska south to California, east to the Rocky Mountains in the U.S. and Alberta; east across northern Canada to Greenland.
Habitat: Open areas, typically where at least seasonally moist, from mid elevations to the alpine.
Sagittaria cuneataarumleaf arrowhead, northern arrowhead, Sagittaria cuneaire, wapato
Distribution: East of the Cascades in Washington; British Columbia south to California, east to New York.
Habitat: Ponds, lake shores and ditches.
Sagittaria graminea
Distribution: Occurring west of the Cascades in Washington; primary distribution is east of the Mississippi River.
Habitat: Wetlands, ponds, and lakes
Sagittaria latifoliacommon arrowhead, duck potato, wapato
Distribution: Occurring on both sides of the Cascades in Washington; Vancouver Island, British Columbia south to central California; primary distribution in central and eastern North America.
Habitat: Ditches, ponds, lakes, swampy areas.
Sagittaria platyphylla
Distribution: Known from the Puget Sound lowlands in Washington; south-central U.S., and in scattered locations in central and northeastern U.S.
Habitat: Pond and lake margins.
Sagittaria rigidasessile-fruited arrowhead
Distribution: Occurring in lowland areas west of the Cascades crest in Washington; California; central U.S. and southern Canada east to northeastern U.S. and Canada; scattered locations elsewhere in U.S. and Canada.
Habitat: Pond and lake margins.
Sagittaria subulataawl-leaf arrowhead
Salicornia depressalow saltwort
Salicornia rubrared glasswort saltwort
Salix albagolden willow, white willow
Distribution: In scattered locations on both sides of the Cascades in Washington;
Habitat: Disturbed areas where moist to wet, often near urban and suburban settings.
Salix amygdaloidespeach-leaf willow
Distribution: East side of the Cascades in Washington; widely distributed throughout North America except in extreme northwestern and southeastern regions.
Habitat: Wetlands, streambanks, and other riparian areas.
Salix arcticaarctic willow
Distribution: Alaska, British Columbia to Labrador; northern Cascades in Washington, Wallowa Mountains in Oregon, and the Rockies in Idaho and Montana
Habitat: In wet to dry areas in the alpine.
Salix barclayibarclay's willow
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.
Salix bebbianaBebb's willow, gray willow, long-beak willow
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.
Salix boothiiBooth's willow
Distribution: In the Cascades of Washington; distributed in western North America from British Columbia east to Saskatchewan, south to California, east to Arizona.
Habitat: Wet subalpine meadows, streambanks, lakeshores, and other riparian areas.
Salix brachycarpashortfruit willow; short-fruited willow; small-fruit willow
Distribution: Occurring east of the Cascades crest in Washington; Yukon Territory south to California, east to the Rocky Mountains; occurring across Canada.
Habitat: Riparian areas at low to moderate elevations.
var. brachycarpa – short-fruited willow, shortfruit willow; short-fruited willow; small-fruit willow
Salix candidasage willow, sage-leaf willow
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.
Salix cascadensisCascade willow
Distribution: In the Cascade Mountains of Washington; British Columbia south in the Cascades to Mt. Rainier, occasionally east to northeast Oregon, Idaho and Montana, south to Utah and Colorado.
Habitat: High elevations in the mountains in subalpine and alpine habitats
Salix columbianaColumbia River willow
Salix commutataunder-green willow, variable willow
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.
Salix drummondianaDrummond's willow
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.
Salix eastwoodiaeSierran willow
Distribution: In the mountains of Washington; Washington south to California, east to Montana, Wyoming, and Nevada.
Habitat: Alpine and subalpine meadows.
Salix exiguacoyote willow, narrow-leaf willow
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
var. exigua – coyote willow, narrow-leaf willow
Salix farriaeFarr's willow
Distribution: Known only from Okanogan County in Washington; Yukon south to Oregon, east to Montana, Idaho and Wyoming.
Habitat: Wet meadows and riparian zones from montane to subalpine.
Salix fragiliscrack willow
Salix geyerianaGeyer's willow
Distribution: Both sides of the Cascades in Washington; widespread in western North America from British Columbia south to California, east to the Rocky Mountains.
Habitat: Lowland riparian areas including streambanks and pond and lake margins.
Salix glauca
var. villosa – glaucous willow, gray willow
Salix hookerianacoastal willow
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.
Salix lasiandraPacific willow
Distribution: Widely distributed throughout Washington; Alaska south to California, east to Manitoba and New Mexico.
Habitat: Riparian areas from the coast to the mountains.
var. caudata – gland willow, Pacific willow, shining willow
var. lasiandra – Pacific willow
Salix lasiolepisarroyo willow
Distribution: Occurring east of the Cascades crest in Washington; Washington south to California, east to Idaho, south to the southern Rocky Mountains and Texas.
Habitat: Riparian corridors from low to moderate elevations.
Salix maccallianaMaccalla's willow
Distribution: East of the Cascades in Washington; Yukon Territory south to Washington, east across northern North America to Quebec.
Habitat: Wet meadows, bogs, fens, streambanks and lakeshores from low to moderate elevations in the mountains.
Salix melanopsisdusky willow
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia south to California, east to the northern and central Rocky Mountains.
Habitat: Riparian zones including streambanks, pond and lake margins, and subalpine meadows.
Salix monochromaone-color willow
Salix nivalisdwarf snow willow
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.
Salix pedicellarisbog willow
Distribution: Chiefly in the Cascades of Washington; Yukon Territory south to Oregon, east across Canada and northern U.S. to the Atlantic Coast.
Habitat: Bogs, fens, and similar wet meadows.
Salix ×pendulinaweeping willow
Salix petrophilaalpine willow
Distribution: Northern Cascades of Washington; British Columbia south to California, east to the Rocky Mountains.
Habitat: Alpine areas, often near melting snowbanks.
Salix planifoliaplane-leaf willow, tea-leaved willow
Distribution: Chiefly in the Cascade Mountains of Washington; widely distributed throughout western North America and across northern half of North America to the Atlantic Coast.
Habitat: Wet meadows, lake margins, streambanks and other riparian areas in the alpine and subalpine.
Salix prolixaMackenzie's willow
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.
Salix pseudomonticolafalse mountain willow
Distribution: Chiefly in the Cascade Mountains in Washington; Alaska to Washington, east to Quebec.
Habitat: Wet meadows, forested wetlands, and other riparian areas in the mountains.
Salix purpureapurple osier, basket willow, purple willow
Salix ×rubenshybrid white willow
Salix scoulerianaScouler's willow
Distribution: Widely distributed throughout Washington; Alaska south to California, east to Manitoba and New Mexico.
Habitat: Moist woods and streambanks, lowlands to moderate elevations in the mountains.
Salix sessilifoliasessile-leaf willow
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia south to Oregon.
Habitat: Riparian corridors at low to moderate elevations.
Salix sitchensisSitka willow
Distribution: Chiefly west of the east base of the Cascades in Washington; Alaska to California, east to Idaho.
Habitat: Moist woods and streambanks, lowlands to moderate elevations in the mountains.
Salix tweedyiTweedy's willow
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.
Salix vestitarock willow
Distribution: North Cascade Mountains in Washington; British Columbia south to Oregon, east across northern North America to the Canadian Maritime Provinces.
Habitat: Moist forest opening, streambanks, and other riparian areas in montane and subalpine habitats.
Salsola tragusRussian thistle, tumbleweed
Distribution: Introduced from Eurasia world-wide in arid regions; chiefly east of the Caascades, southern British Columbia to California.
Habitat: Dry, open ground and wasteland.
Salvia aethiopisafrican sage
Distribution: Introduced from the Mediterranean region to southwest United States, spreading north to eastern Oregon.
Habitat: A weed of dry waste places and roadsides.
Salvia dorrii
Distribution: East of the Cascades in Washington; south to California, east to Utah and Arizona.
Habitat: Dry, open, often sandy or rocky areas in the plains and foothills.
var. incana – fleshy sage, gray-ball sage
Salvia nemorosaBalkan clary
Salvia pratensismeadow clary, prairie-meadow sage
Distribution: Scattered locations on both sides of the Cascades in Washington; escaping in parts of western, central, and eastern North America.
Habitat: Roadsides and other disturbed habitats.
Salvia sclareacleareye
Distribution: Scattered locations on both sides of the Cascades in Washington; occasionally escaping in parts of western, central, and eastern North America.
Habitat: Roadsides and other disturbed areas.
Salvia virgatawand sage
Sambucus nigra
Distribution: Widely distributed throughout Washington; southern British Columbia south to California, east to western Montana and New Mexico.
Habitat: Valley bottoms and open slopes where not too dry, from near sea level to moderate elevations in the mountains.
ssp. caerulea – blue elde, blue elder, blue elderberry
Sambucus racemosa
Distribution: Widely distributed throughout much of Washington; ranging throughout the United States and Canada, except the southern States.
Habitat: A wide variety of areas, typically in forests, fields, and wet areas.
var. melanocarpa – black elderberry
var. racemosa – coast red elderberry
Samolus parvifloruswater pimpernel
Sandbergia perplexapuzzling halimolobos
Distribution: Known from Douglas County in Washington; Washington east toIdaho and Montana.
Habitat: Sagebrush desert, typically on lithosol.
Sandbergia whitediifissurewort, whited's halimolobos fissurewort
Distribution: Occurring east of the Cascades crest in Washington; British Columbia south to Washington.
Habitat: Dry scabland, forest openings, talus slopes and alpine meadows.
Sanguisorba menziesiiMenzies' burnet, small-head burnet
Sanguisorba officinalisgarden burnet, great burnet
Distribution: Alaka to northwest California, chiefly along the coast, inland to Mt. Hood, Oregon, where up to 5000 feet.
Habitat: Muskeg, swamps, and bogs.
Sanguisorba stipulataCanadian burnet, Sitka burnet
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska south to Oregon, east to Idaho in the west, and Illimois to Maine, south to Alabama in the east.
Habitat: Wet places at mid-elevations in the mountains.
Sanicula arctopoidesfootsteps-of-spring, bear's-foot sanicle
Distribution: Along the coast in Washington; Vancouver Island, B.C. south along the coast to California.
Habitat: Maritime species of coastal bluffs and meadows.
Sanicula bipinnatifidapurple black-snakeroot, purple sanicle
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia south to California.
Habitat: Uncommon at low to moderate elevations in dry, open areas.
Sanicula crassicaulis
Distribution: Chiefly west of the Cascades in Washington; British Columbia south to California.
Habitat: Common in meadows and open woods from the coast to low elevations in the mountains.
var. crassicaulis – Pacific sanicle
Sanicula graveolensSierran black-snakeroot
Distribution: Distributed on both sides of the Cascades in Washington; British Columbia south to California, east to Montana and Wyoming.
Habitat: Common in open woods at low to mid-elevations in the mountains.
Sanicula marilandicaMaryland black-snakeroot
Distribution: Eastern British Columbia, northeast Washington, and northern Idaho, east to the Atlantic coast.
Habitat: Moist, low ground, less often on moist, wooded slopes.
Saponaria ocymoidesrock soapwort
Distribution: Garden plant, occasionally escaping but rarely persistent, in the Pacific Coast states and a few states in eastern United States.
Habitat: Old gardens, waste sites and rocky places.
Saponaria officinalisbouncing-bet
Distribution: Introduced throughout the United States; common east of the Cascades in Washington
Habitat: Roadsides and waste ground
Sarcobatus vermiculatusgreasewood
Distribution: East of the Cascade in Washington; Washington south to California, east to the Dakotas, south to Colorado.
Habitat: Saline or alkaline, usually heavy soils of the drier regions.
Sarcocornia perennischickenclaws, glasswort, woody glasswort, woody saltwort glasswort, pickelweed, pickleweed
Distribution: Along the coast in Washington; Alaska south to Baja California, also on Atlantic coast, Europe, and Mediterranean region.
Habitat: Salt marshes and beaches along coast.
Sarracenia flavayellow pitcher plant, yellow trumpet
Distribution: Native in southeastern United States; introduced in western Washington.
Habitat: Swamps, bogs and seeps.
Sarracenia leucophyllawhite-topped pitcher plant
Sarracenia purpurea
ssp. purpurea – northern pitcher plant, purple pitcher plant
Sasa palmatabroadleaf bamboo
Distribution: Occurring in the Puget Sound lowlands in Washington; also known from Tennessee.
Habitat: Disturbed lowland areas where escaping from cultivation.
Saussurea americanaAmerican sawwort
Distribution: Occurring in the Olympic and Cascade Mountains of Washington; Yukon Territory south to California, east to Alberta, Montana, and Idaho.
Habitat: Meadows and open, often rocky slopes, where moist, at mid- to high elevations in the mountains.
Saxifraga adscendenswedge-leaf saxifrage, wedge-leaved saxifrage
Saxifraga bronchialis
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska south to Oregon, east to the Rocky Mountains.
Habitat: Cliff crevices, talus and scree slopes, mid- to high elevations in the mountains.
ssp. austromontana – matted saxifrage, spotted saxifrage
Saxifraga cernuanodding saxifrage
Distribution: Known only east of the Cascades crest in north-central Washington; Alaska south to California, east to the Rocky Mountains and across northern Canada to the Atlantic Coast.
Habitat: Among rocks in alpine areas, often where moist.
Saxifraga cespitosatufted alpine saxifrage, tufted saxifrage
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to south California, east to the Rocky Mountains; east across Canada to the Atlantic Coast.
Habitat: Ledges, gravelly ridges and scree, near sea level to alpine.
Saxifraga hyperboreapygmy saxifrage
Distribution: In the Olympic and Cascade mountains of Washington; Alaska south to California, throughout the Rocky Mountains, across northern Canada to the Maritime Provinces.
Habitat: Alpine tundra, often where moist with rocky outcroppings, crevices, and snowmelt.
Saxifraga mertensianaMerten's saxifrage, woodland saxifrage
Distribution: Distributed on both sides of the Cascades in Washington; Alaska south to California, east to Idaho and Montana.
Habitat: Wet ledges and gravelly streambanks, sea level to subalpine.
Saxifraga oppositifoliapurple saxifrage, twinflowered saxifrage
Distribution: In the Olympic and Cascade mountains of Washington; Alaska south to Oregon, east to the Rocky Mountains; across northern Canada and northeastern U.S.
Habitat: Alpine slopes and rocky outcroppings
ssp. oppositifolia – purple mountain saxifrage, purple saxifrage, twinflowered saxifrage
Saxifraga tridactylitesrue-leaved saxifrage
Saxifraga vespertinamatted saxifrage, spotted saxifrage
Distribution: West of the Cascades crest in Washington; Washington south to Oregon.
Habitat: Rocky outcroppings.
Saxifragopsis fragarioidesstrawberry saxifrage
Distribution: Western United States.
Sceptridium multifidumleathery grapefern
Schedonorus arundinaceustall fescue, tall rye grass
Distribution: Occurring on both sides of the Cascades crest in Washington; widely distributed throughout North America.
Habitat: Meadowlands, fallow fields an ditch banks.
Schedonorus pratensismeadow fescue, meadow rye grass
Distribution: Occurring in scattered localities on both sides of the Cascades crest in Washington; widely distributed throughout North America.
Habitat: Meadows, pastures, roadsides, and other disturbed areas, often where moist
Scheuchzeria palustrisscheuchzeria
Distribution: Southern Alaska south to northern California, east to Labrador and New Jersey.
Habitat: In bogs or on lake margins.
Schizachyrium scoparium
Distribution: Alberta east to Quebec, south through most of the United States east of the rockies; sparingly introduced in the Pacific Northwest.
Habitat: Prairies and foothills.
var. scoparium – broom beardgras, broom bluestem, little bluestem
Schoenoplectus acutus
Distribution: Both sides of the Cascades in Washington; throughout all of North America except southeastern U.S.
Habitat: Pond and lake margins, wetland and riparian areas.
var. acutus – hardstem bulrush, viscous bulrush
var. occidentalis – common tule
Schoenoplectus americanusOlney's three-square bulrush
Schoenoplectus heterochaetusslender bulrush
Schoenoplectus mucronatusricefield bulrush, rough-seed bulrush
Schoenoplectus pungenschairmaker's clubrush, common three square
Distribution: Occurring on both sides of the Cascades crest in Washington; widespread throughout North America.
Habitat: Marshes and wet, low ground; tolerent of alkali.
Schoenoplectus saximontanusRocky Mountain bulrush
Schoenoplectus subterminalisswaying clubrush, water clubrush
Distribution: Chiefly west of the Cascades, southern Alaska to southern Oregon; also in northern Idaho, northwest Montana, and eastern United States.
Habitat: Quiet, shallow water 2-8 dm. deep,
Schoenoplectus tabernaemontanigreat bulrush, soft-stem bulrush
Distribution: Widespread in temperate North America; common throughout the Pacific Northwest, but less so than S. acutus.
Habitat: Marshes and muddy shores of lakes and streams at lower elevations; tolerant of alkali.
Schoenoplectus triqueterrounded three square
Scirpus atrocinctuscommon woolly sedge
Distribution: Known only from Whatcom County in Washington; British Columbia south to Washington, east across the northern half of North America to the Atlantic Coast.
Habitat: Wet, low ground.
Scirpus cyperinuscottongrass bulrush
Distribution: Newfoundland south to Florida, occasionally west across southern Canada to southeast British Columbia and northern Washington.
Habitat: Wet, low ground.
Scirpus microcarpuspanicled bulrush, small fruited bulrush
Distribution: British Columbia to California, east in Canada and northern United States to New England
Habitat: Wet ground from low to moderate elevations in the mountains
Scirpus palliduspale bulrush
Distribution: Southest Washington and northeast Oregon, east to Utah, Minnisota and Texas.
Habitat: Wet, low ground, from the lowlands to moderate elevations in the mountains.
Scleranthus annuusannual knawel
Distribution: Occasional introductions throughout the Pacific Northwest
Habitat: Disturbed soils, waste lots, cultivated areas.
Sclerochloa duracommon hard grass
Distribution: Sparingly introduced in much of western United States; established in eastern Washington and Oregon.
Habitat: Weed of waste areas.
Sclerolinon digynumnorthwestern yellow-flax
Distribution: East of the Cascades in Washington; Washington south to the Sierra Nevada of California, east to Idaho.
Habitat: Meadows and prairies at low to moderate elevations.
Scribneria bolanderiScribner's grass
Scrophularia californica
Distribution: West of the Cascades in Washington, chiefly in coastal counties; British Columbia south to Oregon.
Habitat: Forest margins and prairies at low elevations.
var. oregana – California figwort, Oregon figwort
Scrophularia lanceolatalance-leaf figwort
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia south to California, east across the northern two-thirds of the United States and most of Canada.
Habitat: Moist areas at low elevations, but not along the coast.
Scrophularia nodosacommon figwort
Scutellaria angustifolia
Distribution: East of the Cascades in Washington; British Columbia south to Oregon, southeast to Idaho, Nevada and Utah.
Habitat: Moist and drier sites, moderate to mid-elevations in the mountains.
ssp. angustifolia – narrow-leaved skullcap
Scutellaria galericulatahooded skullcap, marsh skullcapp
Distribution: Both sides of the Cascades in Washington; circumboreal, extending south to California, Arizona and Missouri.
Habitat: Wet meadows and similar habitats at moderate elevations.
Scutellaria laterifloramadweed, mad-dog skullcap
Distribution: Both sides of the Cascades in Washington; occurring throughout North America.
Habitat: Moist bottomlands and meadows, low to moderate elevations.
Secale cerealecultivated rye
Distribution: Widely cultivated, especially in poor, dry soil, often persistent for more than one season.
Habitat: Roadsides and waste ground.
Securigera variapurple crown-vetch, crown vetch
Distribution: Occurring in scattered locations in Washington; widely distributed throughout much of North America.
Habitat: Disturbed areas including wastelots, roadsides, and fields.
Sedum acremossy stonecrop
Distribution: Occurring chiefly west of the Cascades in Washington; British Columbia south to Oregon, east across Canada, and the central, southeastern, and northeastern U.S. to the Atlantic Coast.
Habitat: Disturbed ground.
Sedum albumwhite stonecrop
Distribution: Occurring in scattered locations across Washington; British Columbia south to California, Utah, and in northeastern North America.
Habitat: Disturbed, open areas including fields, lawns, parking areas, and rocky outcroppings.
Sedum brevifoliumshort-leaved stonecrop
Sedum divergensPacific stonecrop, spreading stonecrop
Distribution: Alaska to California, Olympic mountains and the Cascades
Habitat: Open, rocky areas, mid- to high elevations in the mountains
Sedum forsterianumForster's stonecrop
Sedum lanceolatumlance-leaved stonecrop
Distribution: Widely distributed across Washington; Alaska south to California, east to the Rocky Mountains and northern Great Plains in the U.S. and Canada.
Habitat: Usually on rocks or gravel in open, dry areas, from sea level to high elevations in the mountains.
Sedum leibergiiLeiberg's stonecrop
Distribution: Yakima County, Washington, south to northcentral Oregon and east to southeast Washington and western Idaho; along the Snake River.
Habitat: Mossy rocks to open, gravelly hillsides, chiefly in canyons.
Sedum oreganum
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska south to California.
Habitat: Rock ledges, talus slopes and gravelly ridges in the mountains to occasionally near the coast.
var. oreganum – Oregon stonecrop
var. tenue – Oregon stonecrop
Sedum rupicolalance-leaved stonecrop
Distribution: In the Cascades and Olympic Mountains of Washington; Washington east to Idaho.
Habitat: Open, exposed places, usually on rocks or in gravelly soil, at moderate elevations in the mountains.
Sedum spathulifolium
Distribution: West of the Cascades crest in Washington except in the Columbia River Gorge where found as far east as Klickitat County; southern British Columbia south to California.
Habitat: Coastal cliffs, and ledges and gravelly soil in the foothills.
var. spathulifolium – broadleaf stonecrop, spatula-leaf stonecrop
Sedum stenopetalum
Distribution: Occurring chiefly east of the Cascade crest in Washington; British Columbia south to California, east to the northern Rocky Mountains.
Habitat: Grasslands and ponderosa pine forests to sub-alpine ridges, on dry, gravelly benches, rock crevices and talus.
var. monanthum – wormleaf stonecrop
var. stenopetalum – wormleaf stonecrop
Sedum thartiiJenny's stonecrop
Selaginella douglasiiDouglas' spikemoss clubmoss, lesser clubmoss
Distribution: Abundant in the Columbia River Gorge, especially on the Oregon side, west along the river to Portland, OR, and Cowlitz County, WA; also along the Clearwater River in Idaho.
Habitat: Cliffs, banks and tree trunks in humid regions at low elevations
Selaginella oreganafestoon spikemoss, Oregon spikemoss
Selaginella scopulorumcliff spikemoss, Rocky Mountain spikemoss
Selaginella wallaceiWallace's spikemoss
Distribution: British Columbia through central Oregon to California, east to Montana
Habitat: Exposed, terrestrial, often rocky sites, such as pocket of soil in ledges and cliffs
Senecio elmeriElmer's ragwort
Distribution: Occurring in the Cascade and Wenatchee Mountains of central and northern Washington; British Columbia south to Washington.
Habitat: Talus slopes and other rocky places in alpine areas.
Senecio fremontii
Distribution: British Columbia to California, east to Colorado
Habitat: Open, rocky slopes at high elevations in the mountains
var. fremontii – dwarf mountain groundsel
Senecio hydrophiloidessweet marsh butterweed, stout meadow groundsel
Distribution: East of the Cascades, Okanogan County and adjacent British Columbia, south to eastern Oregon and east to western Montana.
Habitat: Wet meadows in the mountains and foothills, but not in alkali.
Senecio hydrophilusalkali marsh butterweed, water groundsel, alkali marsh ragwort
Distribution: East of the Cascades, British Columbia to California, east to South Dakota and Colorado.
Habitat: Swampy places in the valleys and foothills; tolerant of alkali.
Senecio integerrimus
Distribution: Widely distributed throughout most of Washington; British Columbia south to California, east to the central regions of Canada and the U.S.
Habitat: Open areas from the valleys to near timberline.
var. exaltatus – lambstongue groundsel, tall western groundsel
var. ochroleucus – white western groundsel
Senecio jacobaeatansy ragwort
Distribution: Widely distributed on both sides of the Cascades in Washington; British Columbia south to California, east to Idaho and Montana; eastern North America.
Habitat: A weed of pastures, roadsides, forest edges, and other disturbed areas.
Senecio lugensblack-tipped groundsel
Distribution: Alaska and Yukon, south to the Olympic Mountains and the northern mountains in Wyoming; reported in Okanogan County, but otherwise not known in the Cascades.
Habitat: Wet meadows, grassy alpine slopes and rich northern woods.
Senecio minimusAustralian bornweed, toothed coast burnweed
Senecio neowebsteriOlympic Mountain ragwort
Distribution: Olympic Mountains of Washington at high elevations.
Habitat: Talus slopes and rocky places.
Senecio serra
Distribution: Occurring chiefly east of the Cascades crest in Washington; Washington south to California, east to the Rocky Mountains north of Arizona and New Mexico.
Habitat: Meadows and open, moist hillsides, foothills to mid-elevations in the mountains.
var. serra – tall butterweed, butterweed groundsel
Senecio sylvaticuswood groundsel, woodland groundsel, woodland ragwort
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia to California, also in eastern North America.
Habitat: Disturbed ground at low elevations.
Senecio triangularisarrowleaf groundsel, arrowleaf ragwort
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska south to California, east to the Rocky Mountains.
Habitat: Moist places and streambanks, moderate to high elevations in the mountains, and low elvations west of the Cascades.
Senecio viscosussticky ragwort
Senecio vulgariscommon groundsel, old man in the spring
Distribution: Introduced throughout the United States; common west of the Cascades in the Pacific Northwest
Habitat: Roadsides, waste ground
Sericocarpus oregonensis
Distribution: Occurring in the Columbia River Gorge in Washington; Washington south to California.
Habitat: Grasslands, forest openings, and savanna.
ssp. oregonensis – Oregon white topped aster
Sericocarpus rigidusColumbian white-topped aster, Columbian whitetop aster, rigid white topped aster
Distribution: West of the Cascades from southern Vancouver Island, BC, to southwest Oregon, but chiefly in Washington.
Habitat: Prairies and open areas at low elevations.
Setaria faberiChinese foxtail
Setaria italicaItalian bristlegrass, foxtail millet
Setaria pumila
ssp. pallidefusca – yellow foxtail, pigeon grass
ssp. pumila – yellow foxtail
Setaria verticillatahooked bristlegrass, rough bristlegrass
Distribution: Sparingly introduced in the Pacific Northwest; more common in other parts of the United States.
Habitat: Weed of gardens, irrigated areas and wasteland.
Setaria viridis
Distribution: Widely distributed throughout much of Washington; widely distributed throughout much of North America.
Habitat: Disturbed soil and wasteland.
var. viridis – green bristlegrass
Shepherdia canadensisrusset buffalo-berry, soapberry, soopolallie
Distribution: Both sides of the Cascades in Washington; Alaska to Oregon, east to the Atlantic Coast.
Habitat: Moderately dry, open to wooded areas, sea level to mid-elevations in the mountains.
Sherardia arvensisblue field-madder
Distribution: Chiefly west of the Cascades in Washington; British Columbia south to California, east to Idaho and Arizona; introduced from Michigan to Maine, south to Texas to Florida in the east.
Habitat: Weed of prairies, meadows, and other open, disturbed areas.
Sibbaldia procumbenscreeping-glow-wort, creeping sibbaldia
Distribution: Occurring on both sides of the Cascades crest in Washington; widely distributed throughout western North America and northeastern North America; circumboreal.
Habitat: Open, dry to moist subalpine and alpine slopes.
Sidalcea campestrismeadow checker-mallow, meadow sidalcea
Distribution: Native only to the Willamette Valley area (Multnomah and Washington to Benton and Linn counties). Introduced as a garden plant in western Washington, but rarely persisting.
Habitat: Dry fields and roadsides.
Sidalcea hendersoniiHenderson's checker-mallow
Distribution: Along the coast in Washington; Vancouver Island south to the mouth of the Umquah River in Oregon.
Habitat: On or adjacent to tidelands, coastal marshes.
Sidalcea hirtipesbristly-stem checker-mallow
Distribution: Clark and Lewis counties in Washington; south to Lincoln, Tillamook and Clatsop Counties, Oregon.
Habitat: Coastal mountains to bluffs along the ocean, but not on tideflats.
Sidalcea nelsonianaNelson's checker-mallow
Distribution: Occurring in southwest Washington; south in Willamette Valley of Oregon from Portland to Salem, west to Tillamook County.
Habitat: Gravelly, well-drained soil at low elevations.
Sidalcea oregana
Distribution: Chiefly east of the Cascades in Washington; Washington south to California, east to Wyoming.
Habitat: Sagebrush plains, meadows and ponderosa pine forests.
var. calva – Oregon checkermallow
var. oregana – Oregon checkermallow
var. procera – Oregon checkermallow
Sidalcea virgatavirgate checkerbloom
Distribution: Known only from Thurston County in Washington; Thurston County, WA and then Yamhill County, Oregon south along West Cascades to California.
Habitat: Moist prairies and meadows at low elevations.
Silene acaulismoss campion
Distribution: Alaska to Oregon, and south in the Rocky Mountains to Arizona
Habitat: Rock crevices and talus slopes at high elevations in the mountains
Silene antirrhinasleepy catchfly
Distribution: Distributed widely throughout Washington; occurring across North America from low elevations to 10,000 feet.
Habitat: Open areas, often where disturbed.
Silene armeriasweet William catchfly
Distribution: Introduced as an ornmental and occasionally escaping throughout North America.
Habitat: Disturbed soil and wasteland.
Silene bernardinaPalmer's catchfly
Silene conicasand catchfly
Silene conoideaconoid catchfly
Silene coronariarose campion
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia south to California, east to Idaho and Utah; eastern North America.
Habitat: Along roadways, railways and waste land.
Silene csereiibiennial campion
Distribution: Occurring in scattered locations east of the Cascades crest in Washington; British Columbia south to Washington, east across the central and northern U.S. and Canada to the Atlantic Coast.
Habitat: Disturbed areas including fields, roadsides, and wastelots.
Silene dichotomaforked catchfly
Silene dioicared catchfly
Distribution: Occurring in scattered locations in lowland western Washington; British Columbia south to Oregon, east to eastern North America.
Habitat: Disturbed areas, roadsides, and wastelots where escaped from cultivation.
Silene douglasii
Distribution: Widely distributed throughout most of Washington; British Columbia south to California, east to the Rocky Mountains.
Habitat: Sagebrush plains to mountain slopes.
var. douglasii – Douglas's catchfly
var. rupinae – Douglas's catchfly
Silene flos-cuculiragged-robin
Silene gallicawindmill-pink
Distribution: Occurring in the lowlands west of the Cascades crest in Washington; British Columbia south to California, east to Idaho and Arizona; also in the eastern half of the U.S.
Habitat: Weed of disturbed soil and wasteland.
Silene latifoliawhite campion
Distribution: Widely distributed throughout Washington; introduced in much of North America.
Habitat: Well established in undisturbed areas.
Silene menziesiiMenzies' catchfly
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska south to California, east to Montana and New Mexico.
Habitat: Common in open woods from the lowlands to moderate elevations in the mountains.
Silene noctifloranight-flowering catchfly
Distribution: Introduced in much of the United States; more common east of the Cascades in Washington.
Habitat: Grain fields and waste areas.
Silene oreganaOregon catchfly
Distribution: Occurring chiefly east of the Cascades crest in Washington; Washington south to California, east to the Rocky Mountains of Montana, Wyoming, and Utah.
Habitat: Forest openings and meadows from middle elevation to subalpine.
Silene parryiParry's silene
Distribution: Widely distributed across Washington; Alaska south to Oregon, east in the mountains to Montana and Utah.
Habitat: Open areas, mid- to high elevations in the mountains.
Silene repenscampion, pink catchfly campion, creeping silene
Silene scouleri
Distribution: Occuring in localities on both sides of the Cascades in Washington; British Columbia south to California, east to the Rocky Mountains.
Habitat: Prairies and open timberland, low to moderate elevations.
ssp. hallii – Hall's catchfly
ssp. scouleri – Scouler's silene
Silene seelyiSeely's silene
Distribution: Wenatchee Mountains, Kittitas and Chelan Counties, Washington.
Habitat: Cliffs and talus slopes at moderate to mid-elevations in the mountains.
Silene spaldingiiSpalding's silene
Distribution: Occurring in southeastern counties of Washington; southeastern Washington to adjacent northeastern Oregon and western Idaho, also in western Montana.
Habitat: Sagebrush, scabland and ponderosa pine forests.
Silene suksdorfiiCascade catchfly
Distribution: Occurring in the Cascades Mountains in Washington; from Mt. Baker, Washington area south to northern California.
Habitat: Alpine and subalpine slopes, often on talus.
Silene vulgarisbladder campion
Distribution: Occurring in many areas throughout Washington; widely distributed throughout North America except along the southern areas of the U.S.
Habitat: Weed of waste ground, usually at lower elevations.
Silybum marianummilk thistle
Distribution: Introduced weed now well established in California; occasional at scattered locations in the Pacific Northwest.
Habitat: Waste places.
Sinapis albawhite mustard
Distribution: Reported from Whitman County in Washington; widely distributed throughout North America.
Habitat: Waste ground near fields.
Sinapis arvensischarlock, corn mustard, wild mustard
Distribution: Occurring in scattered locations throughout Washington; widely distributed throughout North America.
Habitat: Waste places and other disturbed areas.
Sisymbrium altissimumJim Hill mustard, tumble mustard, tall rocket
Distribution: Distributed throughout Washington but more common east of the Cascades; occurring throughout North America.
Habitat: Shrub-steppe, grasslands, and waste ground, especially following rangeland fires.
Sisymbrium linifoliumlava cress, rush mustard, flax-leaved plainsmustard, Salmon River plainsmustard
Distribution: East of the Cascades crest in Washington; British Columbia south to Arizona (not including California), east to the Rocky Mountains.
Habitat: Sagebrush-steppe communities, rock crevices.
Sisymbrium loeseliifalse london rocket, Loesel's tumblemustard
Distribution: Occurring east of the Cascades in Washington; British Columbia south to Nevada, east to the Atlantic Coast.
Habitat: Roadsides and drier disturbed areas.
Sisymbrium officinalehedge mustard
Distribution: Occurring chiefly west of the Cascades crest in Washington; widely distributed throughout much of North America.
Habitat: Waste ground and other disturbed areas at low elevations.
Sisyrinchium californicumgolden-eyed grass
Distribution: Chiefly west of the Cascades in Washington; southern Vancouver Island, B.C, south to southern California.
Habitat: Wet ground, especially at the edges of lakes and bogs, at low to moderate elevations.
Sisyrinchium idahoense
Distribution: Widely distributed across Washington; British Columbia to California, east to Montana and New Mexico.
Habitat: Vernally wet areas and marshes, near sea level to mid-elevations in the mountains.
var. idahoense – Idaho blue-eyed grass
var. macounii – Macoun's blue-eyed grass
var. occidentale – western blue-eyed grass
var. segetum – cornfield blue-eyed grass, prairie grass
Sisyrinchium littoraleAlaska blue-eyed grass, shore grass
Sisyrinchium sarmentosumpale grass, Suksdorf's blue-eyed grass
Distribution: In the Cascade Mountains of Washington and Oregon near the Columbia River Gorge.
Habitat: Moist, grassy areas.
Sisyrinchium septentrionalenorthern blue-eyed grass
Distribution: Occurring in northeastern Washington; British Columbia east to Saskatchewan, south into northern Washington.
Habitat: Mesic to dry meadows and stream banks.
Sium suavewater parsnip, hemlock water-parsnip
Distribution: Southern British Columbia to central California, east to Newfoundland and Virginia.
Habitat: Swampy places and shallow water, in the valleys and foothills.
Smelowskia americanaalpine smelowskia, Siberian smelowskia
Distribution: In the Olympic and Cascades mountains in Washington; British Columbia and Alberta south to Nevada, east to the Rocky Mountains.
Habitat: Rocky areas at high elevations in the mountains.
Smelowskia ovalisshort-fruited smelowskia
Distribution: In the Cascades Mountains in Washington; British Columbia south to California.
Habitat: Rocky crevices, moraines, ridges and talus slopes in alpine and sup-alpine regions.
Solanum americanumAmerican black nightshade
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia south to California, east along the southern border of the U.S. to the Atlantic Coast.
Habitat: Disturbed open areas, roadsides, waste ground.
Solanum dulcamarafelonwort, bittersweet nightshade, climbing nightshade
Distribution: Widely distributed throughout Washington; widely distributed throughout North America.
Habitat: Thickets, clearings and open woods, usually in moist soil
Solanum elaeagnifoliumwhite horse nettle, silver-leaf nightshade
Solanum lycopersicumtomato
Distribution: Known from scattered locations in Whatcom and King counties in Washington; likely escaping as occasional waif anywhere where cultivated in North America.
Habitat: Sunny, moist, open, disturbed areas.
Solanum nigrumEuropean black nightshade
Distribution: Occurring in scattered locations on both sides of the Cascades crest in Washington; widely distributed throughout North America.
Habitat: Fields, roadsides and other disturbed sites, especially in moister areas; often in urban and suburban areas.
Solanum physalifolium
var. nitidibaccatum – ground-cherry nightshade
Solanum rostratumbuffalo bur, horned nightshade
Distribution: Widely distributed throughout Washington, where it is considered a noxious weed; widely distributed throughout North America.
Habitat: Roadsides and other disturbed areas, often where dry.
Solanum triflorumcut-leaf nightshade
Distribution: East of the Cascades in Washington; widespread throughout North America, except eastern U.S.
Habitat: Weedy native in fields and roadsides, often in undisturbed sites at low to moderate elevations.
Solanum tuberosumirish potato
Solidago elongataCascade Canada goldenrod, West Coast goldenrod
Solidago lepida
Distribution: Both sides of the Cascades in Washington; British Columbia to Idaho and Nevada, east to the Rocky Mountains and Manitoba.
Habitat: Dry to moist areas in meadows and riparian areas, from low to middle elevations.
var. lepida – western Canada goldenrod
var. salebrosa – Canada goldenrod, late goldenrod, meadow goldenrod, Rocky Mountains Canada goldenrod, smooth goldenrod
Solidago missouriensisMissouri goldenrod
Distribution: Southern British Columbia and western Washington, east to Ontario and Tennesee.
Habitat: Rather dry, open places, from the valleys and plains to fairly high elevations in the mountains.
Solidago multiradiatanorthern goldenrod, Rocky Mountain goldenrod
Distribution: Alaska to California, east to Colorado
Habitat: Mountain meadows and open slopes at high elevations
Solidago simplex
Distribution: Occurring in the Olympic and Cascade Mountains in Washington; Alaska to California, east to Minnesota and Texas.
Habitat: Open, slightly moist areas from coastal dunes to alpine meadows.
var. nana – dwarf goldenrod
var. simplex – sticky goldenrod
Soliva sessilislawn burrweed, common soliva, prickly soliva
Distribution: Known from western Washington, Oregon, and British Columbia
Habitat: Disturbed areas, roadsides, lawns
Sonchus arvensis
Distribution: Introduced noxious weed, found across the United States and Canada.
Habitat: Usually in disturbed ground, dry to wet.
ssp. arvensis – field sow-thistle, corn sow thistle, perennial sow thistle
ssp. uliginosus – field sow-thistle, marsh sow thistle, wet ground sow thistle
Sonchus asperprickly sow thistle, spiny leaf sow thistle
Distribution: Cosmopolitan; common in the Pacific Northwest
Habitat: Disturbed areas, roadsides, gardens
Sonchus oleraceuscommon sow thistle
Distribution: Occurring on both sides of the Cascades crest in Washington, but more common on the west side; widely distributed throughout North America.
Habitat: Roadsides and waste ground.
Sorbaria kirilowiigian false spiraea, giant false spiraea
Sorbaria sorbifoliafalse spiraea
Sorbus aucupariaEuropean mountain-ash
Distribution: Introduced, commonly planted species, spread by birds, near habitations.
Habitat: Often in areas where it appears to be native.
Sorbus hybridaSwedish service-tree
Sorbus intermediaSwedish whitebeam
Sorbus scopulina
Distribution: Alaska south to California, east to the Dakotas and Colorado.
Habitat: Open areas, from the foothils to sub-alpine.
var. cascadensis – Cascade mountain-ash
var. scopulina – Greene's mountain ash, western mountain-ash
Sorbus sitchensis
Distribution: In the mountains on both sides of the Cascades and Olympic Mountains in Washington; Alaska south to northern California, east to Idaho and Montana.
Habitat: Forest openings at mid- to high elevations in the mountains.
var. grayi – Sitka mountain-ash
var. sitchensis – Sitka mountain-ash
Sorghum bicolorsorghum
Sorghum halepenseJohnson grass
Distribution: Introduced and established in much of the United States; rarely persistent in the Pacific Northwest.
Habitat: Waste ground, especially where moist.
Sparganium angustifoliumfloating bur-reed, narrow-leaved bur-reed
Distribution: Widely distributed in much of Washington; Alaska south to California, east to the Rocky Mountain states.
Habitat: Ponds and shallow lakes at moderate elevations in the mountains.
Sparganium emersumsimplestem bur-reed
Distribution: Alaska south to California, east to Colorado.
Habitat: Shallow ponds and marshes.
Sparganium eurycarpumbroadfruited bur-reed
Distribution: British Columbia to Baja, California, east to Newfoundland and Florida.
Habitat: Wet meadows to shallow marshes, mostly emersed.
Sparganium fluctuansfloating bur-reed, water bur-reed
Sparganium natansarctic bur-reed, small bur-reed
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska south to California, across the northern half of North America to the Atlantic Coast.
Habitat: Shallow water, mostly in mountain lakes, sometimes completely submersed.
Spartina alterniflorasaltwater cordgrass, smooth cordgrass
Distribution: Introduced in Pacific County, Washington; common along the Atlantic and Gulf Coasts of the United States.
Habitat: Along the coast in brackish water.
Spartina anglicaEnglish cordgrass
Spartina densifloraChilean cordgrass
Spartina gracilisalkali cordgrass
Spartina patenssaltmeadow cordgrass
Spartina pectinatafreshwater cordgrass, prairie cordgrass
Distribution: Eastern Washington and Oregon, east to Newfoundland and North Carolina.
Habitat: Ditches, ponds, and fresh-water marshes.
Spartina ×townsendiiTownsend's cordgrass
Spartium junceumSpanish-broom
Distribution: West of the Cascades in Washington; Washington south to California
Habitat: Disturbed areas, roadsides, forest margins.
Spergula arvensiscorn spurry
Distribution: Introduced in much of the United States; mostly west of the Cascades in Washington and Oregon
Habitat: Weed of waste ground, usually at lower elevations
Spergularia canadensis
Distribution: Along the coast in Washington; Alaska south to California.
Habitat: Coastal tidelands and mudflats.
var. occidentalis – Canadian sandspurry
Spergularia diandraalkali sandspurry
Spergularia macrotheca
Distribution: Along the coast in Washington; British Columbia south to Baja California.
Habitat: Along the sea shore, often in salt marshes and rock crevices in the splash zone.
var. macrotheca – beach sandspurry
Spergularia rubrared sandspurry
Distribution: Occurring throughout Washington; introduced from Europe and common throughout North America.
Habitat: Weed of gardens, waste places, disturbed grasslands and forest openings.
Spergularia salinasaltmarsh sandspurry
Distribution: Both coastal and inland populations in Washington; Native and introduced throughout North America.
Habitat: Saline or brackish areas along the coast, and alkaline areas inland.
Sphaeralcea grossulariifoliagooseberry-leaved globemallow
Distribution: East of the Cascades in Washington; south-central Washington to central Idaho, south to Utah and Nevada.
Habitat: Open desert to the lower levels of the mountains.
Sphaeralcea munroanaMunro's globemallow, white-stemmed globemallow
Distribution: Widely distributed east of the Cascades in Washington; southeast British Columbia and Montana, south to California.
Habitat: Desert plains to open lower mountain slopes.
Sphaerophysa salsulared bladder-vetch
Distribution: Occurring east of the Cascades in Washington; widely distributed in western half of North America except for northwestern provinces and Alaska.
Habitat: Alkaline soil at low elevations.
Sphenopholis intermediaslender wedgescale
Sphenopholis obtusataprairie wedgescale
Spinacia oleraceaspinach
Spiraea densiflora
Distribution: Chiefly in the Cascades and Olympic Mountains of Washington; British Columbia south to California and Nevada, east to Montana and Wyoming.
Habitat: Moist forest openings and rocky slopes, mid- to high elevations in the mountains.
var. densiflora – subalpine spiraea
var. splendens – subalpine spiraea
Spiraea douglasii
Distribution: Alaska to California, east to Idaho; more common west of the Cascades
Habitat: Swamps, lake margins and damp meadows, sea level to subalpine
var. douglasii – Douglas' spiraea
var. menziesii – Menzies' spiraea
var. roseata – western hardhack, Douglas' spiraea, rose spiraea
Spiraea ×hitchcockiiHitchcock's spiraea
Distribution: Currently only known from Pierce County in Washington; Washington south to Oregon.
Habitat: Forest openings at low to moderate elevations in the mountains.
Spiraea lucidashiny-leaf spiraea, shinyleaf spiraea
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia south to Oregon, east to Saskatchewan and Wyoming.
Habitat: Stream banks and open to wooded areas, sea level to high elevations in the mountains.
Spiraea ×pyramidatapyramid spiraea
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to south Oregon, east to Idaho and Montana.
Habitat: Somewhat dry forest openings, moderate to mid-elevations in the mountains.
Spiranthes diluvialisdiluvial ladies'-tresses
Distribution: East of the Cascades in Washington; scattered localities in Colorado, Utah, Wyoming, Idaho and Montana.
Habitat: Moist to wet meadows, marshes, and riparian areas.
Spiranthes porrifoliawestern ladies'-tresses
Distribution: Washington south to California, east to Idaho.
Habitat: Moist to swampy areas.
Spiranthes romanzoffianahooded ladies'-tresses
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska south to California, east to the Rocky Mountains and across the northern U.S. and Canada to the Atlantic Coast.
Habitat: Seasonally moist to swampy areas, sometimes in disturbed areas.
Spirodela polyrrhizaduckmeal, common duckmeat, greater duckweed
Distribution: Widely distributed throughout the United States and southern Canada
Habitat: Quiet water, ponds, marshes and slow-moving streams
Spirodela punctatadotted duckmeat
Sporobolus airoidesalkali-sacaton
Sporobolus compositus
var. compositus – rough dropseed
Sporobolus cryptandrussand dropseed
Distribution: British Columbia south, east of the Cascades, to southern California, east to Ontario, Maine, and most of the United States except the extreme southeast.
Habitat: Sagebrush desert, especilly where sandy, to the foothills and grassland.
Sporobolus neglectussmall dropseed
Stachys arvensisfield hedge-nettle, staggerweed
Distribution: West of the Cascades in Washington near Seattle and Bellingham; British Columbia south to California; Gulf Coast and northeastern U.S.
Habitat: Weed in disturbed areas.
Stachys cooleyaeCooley's hedge-nettle
Distribution: Chiefly west of the Cascades in Washington; Alaska south to California.
Habitat: Forest understory, openings, and margins at low to moderate elevations in the mountains; often where moist.
Stachys mexicanaMexican hedge-nettle
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska south to California.
Habitat: Forest understory, openings, and margins, often where moist.
Stachys pilosa
Distribution: Occurring chiefly east of the Cascades crest in Washington; widely distributed throughout most of North America except extreme southeastern U.S. and northeastern Canada.
Habitat: Swamps, marshes, wetlands and riparian areas.
var. pilosa – marsh betony, swamp hedge-nettle
Stachys rigida
Distribution: Scattered locations mostly west of the Cascades in Washington; south to California and adjacent Nevada.
Habitat: Stream banks and moist bottom lands, mostly at low elevations.
var. rigida – rigid hedge-nettle
Stellaria alsinebog stichwort
Distribution: Occurring west of the Cascades crest in Washington; British Columbia south to Washington in western North America; native to eastern North America; also introduced in Chile.
Habitat: Streambanks, culverts, ditches, and moist forest edges, typically where disturbed.
Stellaria borealis
Distribution: Alaska to California, east to New York and Wyoming.
Habitat: Moist areas, rocky slopes and meadows.
ssp. borealis – boreal starwort
ssp. sitchana – boreal starwort
Stellaria calycanthanorthern bog starwort
Distribution: Circumpolar, south in North America to California, Michegan and New York.
Habitat: Moist meadows and steam banks, low to high elevations.
Stellaria crispacrisped starwort
Distribution: Alaska to California, east to Alberta and Wyoming.
Habitat: Moist areas in the lowlands and lower mountains.
Stellaria gramineagrass-leaf starwort
Distribution: Introduced and abundant in eastern United States; occasional in western Washington and Idaho.
Habitat: Chiefly in lawns.
Stellaria humifusasaltmarsh starwort
Distribution: Occurring along the coast in Washington; Alaska south to Oregon, east across Canada to the Atlantic coast; circumpolar.
Habitat: Salt marshes.
Stellaria longifolialong-leaved starwort
Distribution: Occurring on both sides of the Cascades crest in Washington; widely distributed throughout North America except in the south-central and southeastern U.S.
Habitat: Wet meadows, swamps, marshes, forested wetlands at low to moderate elevations.
Stellaria longipes
Distribution: Widely distributed throughout Washington; Alaska south to California, east to New York and New Mexico.
Habitat: Moist streambanks and rocky slopes at mid-elevations in the mountains.
ssp. longipes – Goldie's starwort
Stellaria mediacommon chickweed
Distribution: Widely distributed throughout most of Washington; widely distributed throughout North America.
Habitat: Disturbed areas, often where moist in spring; very common.
Stellaria neglectagreater chickweed
Stellaria nitensshiny starwort
Distribution: British Columbia to Baja California, east to Idaho and Utah.
Habitat: Gravelly prairies and stream banks to grassy hillsides at low elevations.
Stellaria obtusablunt-sepaled starwort
Distribution: Occurring on both sides of the Cascades in Washington; British Columbia south to California, east to the Canadian and Southern Rocky Mountains.
Habitat: Moist forest and riparian zone understory, talus slopes, from low to moderate elevations.
Stellaria pallidalesser chickweed
Stellaria umbellataumbrella starwort
Distribution: Occurring chiefly east of the Cascades crest in central and south-central Washington; Alaska south to California, east to Northwest Territories, south throughout western U.S.
Habitat: Wetlands, riparian zones, stream banks.
Stenotus lanuginosus
Distribution: Occurring east of the Cascades crest in Washington; Washington south to California, east to Idaho, Montana, and Nevada.
Habitat: Open, dry, often rocky places, foothills to moderate elevations in the mountains.
var. lanuginosus – woolly goldenweed, woolly stenotus
Stephanomeria exigua
ssp. exigua – skeletonplant, small wirelettuce
Stephanomeria paniculatastiff branched stephanomeria, stiff branched wirelettuce
Distribution: Occurring east of the Cascades in Washington; Oregon and adjacent Idaho, south to California.
Habitat: Dry, open places in the plains and foothills.
Stephanomeria tenuifoliawire lettuce, narrowleaf stephanomeria
Distribution: East of the Cascades in Washington; southern British Columbia south to California, east to Texas and western Montana.
Habitat: Dry, often rocky places, from the foothills and plains to moderate elevations in the mountains.
Streptanthella longirostrislong-beaked fiddle mustard, streptanthella
Distribution: Occurring in south-central Washington; Washington south to California, east to Wyoming and New Mexico.
Habitat: Open desert and sagebrush slopes.
Streptopus amplexifoliuscucumber root, clasping twisted stalk, clasp-leaf twisted-stalk, clasping twisted-stalk
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains, also in northeastern North America.
Habitat: Open to dense moist forests from low elevations to subalpine.
Streptopus lanceolatusrosy twisted stalk
Distribution: Distributed throughout the Olympic and Cascade mountains in Washington; Alaska south to Oregon.
Habitat: Streambanks and damp woods at moderate to high elevations in the mountains.
Streptopus streptopoideskruhsea, Kruhsea
Stuckenia filiformis
Distribution: Only known from Whatcom County in Washington; Alaska south to California, east to the Rocky Mountains; east across Canada to the Atlantic Coast and Greenland.
Habitat: Lakes, ponds, slow moving waters.
ssp. alpina – slender-leaved pondweed
ssp. occidentalis – western pondweed, threadleaf-pondweed
Stuckenia pectinatafennel-leaved pondweed, sago pondweed, sago-pondweed
Distribution: Both sides of the Cascades in Washington; common throughout North America; Eurasia
Habitat: Shallow, fresh to brackish water.
Stuckenia vaginatabigsheath-pondweed
Suaeda calceoliformispaiuteweed, common seablite, horned seablite, pahute weed
Distribution: Occurring on both sides of the Cascades crest in Washington; widely distributed throughout North America from Alaska south 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.
Suaeda nigrabushy seablite seepweed
Suaeda occidentalisslender seablite, western seepweed
Distribution: Eastern Washington to northern Nevada, east through southern Idaho to Colorado.
Habitat: Saline or alkaline flats and marshes in sagebrush area.
Subularia aquatica
Distribution: Known from a few locations in northwestern Washington; Alaska to California, east to the Rocky Mountains and across the northern U.S. and Canada to the Atlantic Coast.
Habitat: Shallow water or mud flats of ponds, lakes, slow-moving streams, tidal flats, wet meadows, and marshes.
ssp. americana – awlwort
Suksdorfia violaceaviolet mock brookfoam
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia south to Oregon, east to Alberta, Montana and Idaho.
Habitat: Vernally moist mossy banks and rock crevices.
Sullivantia oreganaOregon coolwort
Distribution: Columbia River Gorge and lower Willamatte Valley, Oregon.
Habitat: On moist cliffs, especially near waterfalls.
Swertia perennisalso felwort, alpine bog swertia
Distribution: Narrowly distributed in Cascades of Washington; Alaska south to California, east through the Rocky Mountains.
Habitat: Streambanks, wet meadows and other moist places, mid- to high elevations in the mountains.
Symphoricarpos albus
Distribution: Widely distributed throughout Washington; Alaska south to California, east across Canada and northern United States to the Atlantic Coast.
Habitat: Thickets and open slopes, lowlands to mid-elevations in the mountains.
var. albus – common snowberry
var. laevigatus – common snowberry
Symphoricarpos molliscreeping snowberry
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia south to California, east to Idaho and Nevada.
Habitat: Slopes and forest edges, often where wet.
var. hesperius – creeping snowberry, spreading snowberry
Symphoricarpos occidentaliswestern snowberry, wolfberry
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.
Symphoricarpos rotundifolius
Distribution: Chiefly east of the Cascades in Washington; British Columbia south to California and New Mexico.
Habitat: Open slopes and dry meadows, foothills to high elevations in the mountains.
var. vaccinoides – mountain snowberry
Symphyotrichum ×amethystinumamethyst aster, hybrid aster
Symphyotrichum ascendensintermountain aster, long leaved aster, long-leaved aster, western American aster, western aster
Distribution: Occurring east of the Cascades crest in Washington; British Columbia south to California, east to the Rocky Mountains and northern Great Plains.
Habitat: Meadows, grasslands, and forest openings, often where moist.
Symphyotrichum borealenorthern bog aster, rush aster, slender white aster
Distribution: Alaska south to Idaho, east to Minnesota; rare in the Pacific Northwest.
Habitat: Cold bogs.
Symphyotrichum bracteolatumbracted aster, Eaton's aster, Oregon aster
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Sasketchewan and Rocky Mountain states.
Habitat: Moist to wet sunny places, wet thickets, along streams and ditches
Symphyotrichum campestrewestern meadow aster, Western meadow aster
Symphyotrichum chilense
Distribution: Both sides of the Cascades, Washington to California, east to Montana and New Mexico.
Habitat: Dry, open places in the valleys and plains, to moderate elevations in the mountains.
var. chilense – common California aster, Pacific aster
Symphyotrichum ciliatumalkali American aster, rayless alkali aster, rayless annual aster
Distribution: Occurring east of the Cascades in northern Washington; British Columbia south to northern Washington, east to Minnesota.
Habitat: Moist, usually saline ground, often along the shores of lakes and ponds.
Symphyotrichum cusickiiCusick's American aster, Cusick's aster
Distribution: Occurring east of the Cascades crest in Washington; Washington south to Oregon, east to Alberta, Idaho, and Montana.
Habitat: Moist, often wooded places at moderate to high elevations in the mountains.
Symphyotrichum ericoides
Distribution: Occurring chiefly east of the Cascades crest in Washington; southern British Columbia and eastern Washington and Montana, south to Utah, Colorado and Nebraska.
Habitat: Open, wet or dry places in the valleys and plains; tolerant of alkali.
var. pansum – little gray aster, tufted white prairie aster, white heath aster
Symphyotrichum falcatum
Distribution: Occurring east of the Cascades crest in Washington; Alaska south through the Rocky Mountain states to Arizona, east to Ontario, the Great Lakes region and the Great Plains.
Habitat: Streambanks, open slopes, edges of alkali lakes and flats, grasslands, and mesic montane habitats.
var. commutatum – rough white prairie aster, western heath aster
Symphyotrichum foliaceum
Distribution: Alaska to California, east to Colorado
Habitat: Open, usually moist areas, low to high elevations in the mountains.
var. apricum – alpine leafybract aster, leafy aster, leafy-bracted aster
var. canbyi – Canby's leafybract aster
var. foliaceum – alpine leafybract aster, leafy aster, leafy-bracted aster
var. parryi – alpine leafybract aster, leafy aster, leafy-bracted aster, Parry's aster
Symphyotrichum frondosumalkali aster, short rayed aster, short-rayed alkali aster
Distribution: Eastern Washington, south to California and east to Wyoming and Utah.
Habitat: Moist, usually saline soil, often along the shores of lakes and ponds, or in vernally moist, alkaline bottoms.
Symphyotrichum halliiHall's aster
Distribution: West of the Cascades in Washington and, more commonly, in Oregon.
Habitat: Dry, open places in the valleys and plains.
Symphyotrichum hendersoniiHenderson's aster, Kootenai aster
Distribution: Occurring in northeastern region of Washington; Washington south to Oregon, east to Idaho and Montana.
Habitat: Moist, often wooded places at moderate to high elevations in the mountains.
Symphyotrichum jessicaeJessica's aster, Palouse aster
Distribution: Occurring in southeastern Washington; southeastern Washington and adjacent Idaho.
Habitat: Streambanks and open places.
Symphyotrichum laeve
Distribution: Eastern British Columbia, eastern Washington and northeast Oregon, east to Maine and Georgia.
Habitat: Open places in the plains and valleys to moderate elevations in the mountains.
var. geyeri – smooth aster
Symphyotrichum lanceolatum
var. hesperium – lance-leaved aster, panicled aster, white panicled aster
Symphyotrichum novae-angliaeNew England aster
Distribution: Native to eastern United States; introduced as an ornamental and occasionally escaping in the Pacific Northwest.
Habitat: Roadsides and disturbed areas where somewhat moist.
Symphyotrichum spathulatum
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia south to California, east to the Rocky Mountains.
Habitat: Meadows and forest openings, moderate to mid-elevations in the mountains.
var. spathulatum – western aster, western mountain aster, Western mountain aster
Symphyotrichum subspicatumDouglas' aster, Douglas's aster
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia south to California, east to Alberta, Montana and Idaho.
Habitat: Moist woods, streambanks and seashores.
Symphytum asperumprickly comfrey, rough comfrey
Distribution: Introduced and occasionally escaped from cultivation, scattered in the United States; chiefly west of the Cascades in Washington.
Habitat: Roadsides and other disturbed habitats.
Symphytum grandiflorumcreeping comfrey
Symphytum officinalecommon comfrey
Distribution: Distributed west of the Cascades in Washington; widely distributed throughout North America except in extreme north and south states/provinces.
Habitat: Escaped from cultivation, often found in disturbed areas.
Symphytum orientalewhite comfrey
Symphytum ×uplandicumhybrid comfrey
Synthyris missuricamountain kittentails
Distribution: Columbia River Gorge, southeast Washington and northeast Oregon, east to Idaho and Montana and south to California
Habitat: Moist ground, foothills to mid-elevations in the mountains
Synthyris pinnatifida
Distribution: Olympic Mountains of Washington; also in central Idaho, Utah, western Wyoming and southwest Montana.
Habitat: Open, often rocky slopes, at high elevations in the mountains.
var. lanuginosa – cut-leaf kittentails
Synthyris reniformis
Distribution: Occurring west of the Cascades crest in Washington; Washington south to California.
Habitat: Coniferous woods, less commonly in open areas, at low elevations.
var. reniformis – round-leaved kittentails, snow queen
Synthyris schizanthafringe-petal kitten's-tail
Distribution: In the Olympics and Cascades foothills of western Washington; Washington south to northwest Oregon.
Habitat: Uncommon on moist ground at mid-elevations in the mountains.