Vascular Plants

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


Browse by scientific name:

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Scientific names beginning with P:
Packera bolanderiBolander's groundsel
Distribution: Along the coast from the estuary of the Columbia River to California.
Habitat: Bluffs, woodlands and beaches.
Origin: Native
Flowers: June-July
var. bolanderi – Bolander's groundsel, Bolander's ragwort
var. harfordii – Harford's ragwort
Packera canawoolly groundsel
Distribution: Occurring east of the Cascades crest in Washington; British Columbia south to California, east to Saskatchewan and Nebraska.
Habitat: Dry, open, often rocky places, from the foothills to above timberline.
Origin: Native
Flowers: May-August
Packera conterminadwarf arctic butterweed
Origin: Native
Packera flettiiFlett's groundsel
Distribution: From the foothills to the tops of the Olympic Mountains in Washington, and also at high elevations in the Cascades in the vicinity of Mount Rainier.
Habitat: Open, rocky places, especilly on talus slopes.
Origin: Native
Flowers: June - August
Packera indecorarayless mountain butterweed, elegant groundsel, rayless mountain groundsel
Distribution: Alaska to Washington, east to Montana
Habitat: Uncommon in moist woods and on stream banks, moderate elevations in the mountains
Origin: Native
Flowers: July - August
Packera macouniiPuget butterweed, long rayed groundsel, Macoun's groundsel, Siskiyou Mountain ragwort
Distribution: West of the Cascades, British Columbia to southern Oregon, mostly in the Puget Trough.
Habitat: Open woods and dry, open places.
Origin: Native
Flowers: May - July
Packera pauciflorarayless alpine butterweed, rayless alpine groundsel
Distribution: Alaska, east across Canada to Labrador, south to northern Washington and Idaho.
Habitat: Alpine and sub-alpine meadows and moist cliffs.
Origin: Native
Flowers: July - August
Packera pauperculaCanadian butterweed, balsam groundsel
Distribution: Occurring east of the Cascades in Washington; British Columbia south to Oregon and New Mexico, east to Labrador and Virginia.
Habitat: Meadows, moist cilffs and woods, foothills to moderate elevations in the mountains.
Origin: Native
Flowers: May-October
Packera porteriPorter's groundsel
Origin: Native
Packera pseudaureastreambank butterweed
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia south to California, east to central Canada and midwestern U.S.
Habitat: Wet meadows, stream-banks and moist woodlands at moderate to mid-elevations in the mountains.
Origin: Native
Flowers: June-August
var. pseudaurea – streambank butterweed, falsegold groundsel
Packera streptanthifoliaRocky Mountain butterweed, cleftleaf groundsel, Rocky Mountain groundsel
Distribution: Alaska to California, east to Colorado
Habitat: Moist to moderately dry open areas and woods, mid- to high elevations in the mountains
Origin: Native
Packera subnudaalpine meadow butterweed, few-leaved groundsel
Distribution: Occurring in the Cascade Mountains of Washington; Washington south to California, east to Montana and Wyoming.
Habitat: Alpine and subalpine wet meadows.
Origin: Native
Flowers: July-September.
var. subnuda – cleftleaf groundsel
Paeonia browniibrown's peony, western peony
Distribution: Occurring east of the Cascades crest in Washington; Washington south to California, east to Montana, south to Utah.
Habitat: Sagebrush deserts to ponderosa pine forests.
Origin: Native
Flowers: May-June
Panicum capillarewitchgrass
Distribution: Introduced and weedy in much of the United States and southern Canada.
Habitat: Moist and irrigated areas, along streams and around ponds.
Origin: Native
Flowers: June - September
ssp. capillare – or common panicgrass, witchgrass
Panicum dichotomiflorumfall panicum
Distribution: Native in most of central and eastern United States; occasionally introduced in Washington.
Habitat: Waste ground.
Origin: Introduced
Flowers: May - September
ssp. dichotomiflorum – fall panicum, western witchgrass
Panicum miliaceummillet
Distribution: Introduced and cultivated in many parts of the United States; occasionally escaping and persisting in the Pacific Northwest.
Habitat: Abandoned fields, roadsides, waste ground.
Origin: Introduced
Flowers: July - September
ssp. miliaceum – broomcorn, hog millet, panic millet, proso millet
ssp. ruderale – broomcorn, hog millet, panic millet
Papaver argemonelong prickly-head poppy
Distribution: Introduced from Europe and occasionally escaping, established in scattered localities east of the Cascades in Washington.
Habitat: Disturbed soil.
Origin: Introduced from Europe
Flowers: May - June
Papaver dubium
Distribution: Introduced in much of eastern United States; occasional in Washington.
Habitat: Fields, dunes, marshy areas, roadsides, disturbed sites.
Origin: Introduced
Flowers: May - July
Papaver rhoeascorn poppy
Distribution: Widely introduced and often escaping in scattered locations in the Pacific Northwest.
Habitat: Disturbed ground, old fields.
Origin: Introduced from Europe
Flowers: June - July
Papaver somniferumopium poppy
Distribution: Introduced and often escaping from cultivation, persisting for a short time.
Habitat: Waste areas, roadsides.
Origin: Introduced from Eurasia
Flowers: June - July
Parameconopsis cambrica
Distribution: Occurring in lowland western Cascades in Washington; southern British Columbia to Washington, perhaps introduced elsewhere.
Habitat: Forest edges where disturbed.
Origin: Introduced
Flowers: May-June
Parapholis incurvasicklegrass
Origin: Introduced
Parathelypteris nevadensisSierran marsh fern
Origin: Native
Parietaria judiacapellitory-of-the-wall
Origin: Introduced from Africa and Eurasia
Parietaria officinaliseastern pellitory-of-the-wall
Origin: Introduced from central and southern Europe
Parietaria pensylvanicaPennsylvania pellitory
Distribution: Occurring east of the Cascades crest in Washington; Yukon Territory south to California, east across southern Canada and the U.S. to the Atlantic Coast.
Habitat: Woods to shaded banks, beneath ledges of large rocks, from low to middle elevations.
Origin: Native
Flowers: May-September
Parnassia cirrataCascade grass-of-parnassus
Origin: Native
var. intermedia – Cascade Grass-of-Parnassus
Parnassia fimbriatafringed Grass-of-Parnassus, fringed grass of parnassus
Distribution: Occurring on both sides of the Cascades in Washington; Alaska to California, east to Alberta, Montana and New Mexico.
Habitat: Bogs, stream banks and wet meadows, mid- to high elevations in the mountains.
Origin: Native
Flowers: July-September
Parnassia kotzebueiKotzebue's Grass-of-Parnassus
Distribution: Known only from Okanogan and Chelan counties in Washington; Arctic Alaska south to Chelan County, WA, east across northern Canada to Labrador, east in the U.S. to the Rocky Mountains.
Habitat: Moist subalpine meadows, cliff faces, and ledges, often in boggy soil.
Origin: Native
Flowers: July-September
Parnassia palustrisGrass-of-Parnassus, northern grass-of-parnassus
Distribution: Primarily west of the Cascades in Washington on the Olympic Peninsula and southwestern counties; Arctic America south to Minnesota and British Columbia, in the Rocky Mountains to Colorado and in parts of the Sierra Nevada in California.
Habitat: Arctic tundra to moist, shaded areas in the mountains, where usually along streams or around springs.
Origin: Native
Flowers: July-August
Parnassia parviflorasmall-flowered Grass-of-Parnassus
Origin: Native
Parthenocissus vitaceathicket-creeper
Distribution: Scattered locations chiefly east of the Cascades in Washington; native to eastern and central U.S.
Habitat: Disturbed, moist areas.
Origin: Introduced from elsewhere in United States
Flowers: May-July
Pascopyrum smithiiwestern-wheat grass
Origin: Native
Flowers: June - August
Paspalum distichumknotgrass, Thompsongrass
Distribution: Occurring chiefly along the lower Columbia River corridor in Washington; occurring in most of western North America and the southeastern U.S.
Habitat: Along ditches and streams where the soil is moist much of the season.
Origin: Native
Flowers: August-October
Pastinaca sativacommon parsnip, wild parsnip
Distribution: Introduced and widely naturalized in North America; found in scattered locations in the Pacific Northwest.
Habitat: Roadsides, ditchbanks and other disturbed sites.
Origin: Introduced; native to Europe
Flowers: May - July
Paulownia tomentosaprincess tree
Distribution: Known from King and Skamania counties in Washington; occurring from the Great Lakes region south to Texas, east to the Atlantic Coast.
Habitat: Disturbed, open areas often relatively close to sites where trees are being cultivated.
Origin: Introduced
Flowers: May-June
Paxistima myrsinitesOregon boxleaf
Distribution: Widely distributed on both sides of the Cascades in Washington; British Columbia south to California, east to the Rocky Mountains.
Habitat: Mid-elevations in the mountains, but coastal in the Puget Sound region.
Origin: Native
Flowers: April-June
Pectiantia brewerifeathery bishop's-cap, Brewer's mitrewort
Distribution: Occurring on both sides of the Cascades Crest in Washington; British Columbia south to California, east to Alberta, Montana, Idaho, and Nevada.
Habitat: Moist mountain valleys and open to wooded slopes, from mid-elevations to timberline.
Origin: Native
Flowers: May-August
Pectiantia ovaliscoastal bishop's cap, coastal mitrewort
Distribution: Occurring west of the Cascades crest in Washington; British Columbia south to California.
Habitat: Deep, moist woods, creek bottoms and wet banks.
Origin: Native
Flowers: March-May
Pectiantia pentandrafive-stamen bishop's-cap, alpine mitrewort
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska south to California, east to the Rocky Mountains of Canada and the U.S.
Habitat: Wet meadows and moist woods, especially along streams, lowlands to mid-elevations in the mountains.
Origin: Native
Flowers: June-August
Pectocarya penicillatashortleaf combseed, winged pectocarya
Distribution: East of the Cascades, southern British Columbia to Baja California, east to Idaho and Utah.
Habitat: Dry, open areas, often in sandy soil and among sagebrush, at low elevations.
Origin: Native
Flowers: April - June
Pectocarya setosabristly combseed
Distribution: Occurring east of the Cascades crest in Washington; Washington south to California, east to Idaho, Utah, and New Mexico.
Habitat: Open areas in sagebrush-steppe habitat.
Origin: Native
Flowers: May-June
Pedicularis bracteosabracted lousewort
Distribution: Widely distributed throughout the mountainous areas of Washington; British Columbia south to California, east to Montana, Colorado and New Mexico.
Habitat: Common in open forests at moderate to high elevations in the mountains.
Origin: Native
Flowers: June-August
var. atrosanguinea – bracted lousewort
var. bracteosa – bracted lousewort
var. flavida – bracted lousewort
var. latifolia – bracted lousewort
var. pachyrhiza – bracted lousewort
var. siifolia – bracted lousewort
Pedicularis contortawhite coiled-beak lousewort
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Montana and south to Wyoming.
Habitat: Open wooded slopes and drier meadows at high elevations in the mountains.
Origin: Native
Flowers: June-August
var. contorta – white-coiled beak lousewort
Pedicularis groenlandicabull elephant's-head, elephant's head
Distribution: Alaska to California, east to Montana, Colorado and New Mexico
Habitat: Seeps, lake shores and other wet areas at mid- to high elevations in the mountains
Origin: Native
Flowers: June - August
Pedicularis ornithorhynchosduck's-bill, bird's beak lousewort
Distribution: In the Cascades of Washington; Alaska south to Washington.
Habitat: High mountain meadows.
Origin: Native
Flowers: July-September
Pedicularis pulchellapretty dwarf lousewort
Origin: Native
Pedicularis racemosaleafy lousewort, sickletop lousewort
Distribution: Widely distributed across Washington; British Columbia south to California, east to Montana, Colorado and New Mexico.
Habitat: Coniferous forests at mid-elevations in the mountains.
Origin: Native
Flowers: June-September
var. alba – sickletop lousewort
var. racemosa – sickletop lousewort
Pedicularis rainierensisMt. Rainier lousewort
Distribution: Endemic to Mt. Rainier and adjacent areas.
Habitat: Moist alpine meadows.
Origin: Native
Flowers: July-August
Pediocactus nigrispinussnowball cactus
Distribution: Endemic to central Washington, Chelan to Yakima Counties.
Habitat: Often with sagebrush, desert valleys to low mountains.
Origin: Native
Flowers: May-July
ssp. nigrispinus – dark-spine ball cactus
Peganum harmalaAfrican rue
Origin: Introduced
Flowers: June - August
Pellaea brachypteraSierran cliffbrake
Origin: Native
Pellaea breweriBrewer's cliffbrake
Distribution: East slope of the Cascades, Washington to California, east to Montana and Utah
Habitat: Talus slopes, cliff crevices and other rocky places, foothills to timberline
Origin: Native
Pellaea gastonyiGastony's cliff-brake
Origin: Native
Pellaea glabellasmooth cliff-brake
Origin: Native
ssp. simplex – simple cliffbrake
Peltandra virginicaarrow arum, tuckahoe
Origin: Introduced
Pennisetum glaucumpearl millet
Origin: Introduced
Pennisetum setaceumtender fountaingrass
Origin: Introduced from the eastern Mediterranean
Penstemon acuminatussand dune penstemon, sharp-leaved penstemon
Distribution: Douglas County south to Klickitat Count, east to Franklin County; Washington south to Wasco County, Oregon, also in southeastern Oregon and adjacent southwestern Idaho.
Habitat: Dry, open, sandy places at low elevations.
Origin: Native
Flowers: April-June
var. acuminatus – sand dune penstemon, sharp-leaved penstemon
Penstemon attenuatussulphur penstemon, taper-leaved penstemon
Distribution: Occurring east of the Cascades crest in Washington; Washington south to Oregon, east to western Montana and southern Idaho.
Habitat: Drier meadows and moist, open to wooded slopes in the mountains and foothills.
Origin: Native
Flowers: June-August
var. attenuatus – sulphur penstemon, taper-leaved penstemon
Penstemon barrettiaeBarrett's beardtongue
Distribution: Endemic to the Klickitat River canyon and the east end of the Columbia River Gorge in Washington and Oregon.
Habitat: Dry soil at low elevations.
Origin: Native
Flowers: April-May
Penstemon cardwelliiCardwell's beardtongue
Distribution: Skamania County, Washington, south on the west slopes of the Cascades to the Klamath region of southwest Oregon, and north in the Coast Range to Tillamook County.
Habitat: Open or wooded summits or slopes at moderate elevations in the mountains.
Origin: Native
Flowers: Late May - July
Penstemon confertuslesser yellow beardtongue
Distribution: Chiefly east of the Cascades crest in Washington; British Columbia to Oregon, east to Idaho and Montana.
Habitat: Open woods at mid-elevations in the mountains.
Origin: Native
Flowers: May-August
Penstemon davidsoniiDavidson's penstemon
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia south to California and Nevada.
Habitat: Open, rocky areas, mid- to high elevations in the mountains.
Origin: Native
Flowers: June-August
var. davidsonii – Davidson's beardtongue
var. menziesii – Davidson's beardtongue
Penstemon deustushot-rock penstemon
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to Montana and Utah.
Habitat: Dry sites at moderate to mid-elevations in the mountains.
Origin: Native
Flowers: May-July
var. deustus – hot-rock penstemon
var. variabilis – hotrock penstemon, scabland penstemon, scorched penstemon
Penstemon diphyllustwo-leaf beardtongue
Origin: Native
Flowers: Late June - October
Penstemon ellipticusrockvine beardtongue
Distribution: Southwest Alberta, southeast British Columbia, northern Idaho and northwest Montana.
Habitat: Rocky places at high elevations in the mountains, often on cliffs, ledges, or in rock crevices.
Origin: Native
Flowers: Late June - September
Penstemon eriantheruscrested tongue penstemon, fuzzy penstemon
Distribution: Southeast British Columbia, central Washington and central Oregon, east to North Dakota and Nebraska.
Habitat: Dry, open places in the valleys, plains and foothills, sometimes ascending to moderate elevations in the mountains.
Origin: Native
Flowers: May - July
var. eriantherus – fuzzy-tongue penstemon
var. whitedii – fuzzy-tongue penstemon
Penstemon euglaucusglaucous beardtongue
Distribution: In Washington from Mt. Adams south; Washington south to central Oregon.
Habitat: Dry, sandy, open or sparsely wooded slopes at moderate elevations to subalpine meadows.
Origin: Native
Flowers: June-September
Penstemon fruticosusbush penstemon, shrubby penstemon
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia south to Oregon, east to Montana and Wyoming.
Habitat: Common in rocky, open or wooded areas, foothills to rather high elevations in the mountains.
Origin: Native
Flowers: May-August
var. fruticosus – shrubby penstemon
var. scouleri – shrubby penstemon
var. serratus – shrubby penstemon
Penstemon gairdnerigairdner's penstemon
Distribution: East of the Cascades in Washington; Washington south to Oregon, east to Idaho.
Habitat: Dry, open sagebrush desert and scablands, low to moderate elevations in the mountains.
Origin: Native
Flowers: May-June
var. gairdneri – Gairdner's penstemon
Penstemon glandulosusglandular penstemon
Distribution: Along the east base of the Cascades, Chelan to Klickitat Counties, Washington, and at scattered locations in Oregon and Idaho.
Habitat: Open, often rocky hillsides and banks in the foothills, valleys, and lower mountains.
Origin: Native
Flowers: May-July
var. chelanensis – sticky-stem penstemon
var. glandulosus – sticky-stem penstemon
Penstemon hesperiustall beardtongue
Origin: Native
Penstemon humilislowly penstemon
Distribution: Occurring east of the Cascades crest in Washington; Washington south to California, east to the Rocky Mountains.
Habitat: Dry, open, often rocky places, frequently with sagebrush, from the plains and foothills to high elevations in the mountains.
Origin: Native
Flowers: May-July
var. humilis – lowly penstemon
Penstemon ovatusegg-leaf beardtongue, broad-leaved penstemon
Distribution: Occurring on both sides of the Cascades crest in Washington; southern British Columbia south to northern Oregon.
Habitat: Open woods below 3000 feet in elevation.
Origin: Native
Flowers: May-August
Penstemon palmeriPalmer's penstemon
Distribution: Reported from Spokane County in Washington; Washington south to California, east to the Rocky Mountains.
Habitat: Roadsides where seeded for soil stabilization.
Origin: Introduced from southwestern United States
Flowers: May-July
var. palmeri – Palmer's penstemon
Penstemon pennellianusBlue Mountain beardtongue
Distribution: In Washington occurring in the Blue Mountains in the southeast corner of the state; Washington south to east-central Oregon.
Habitat: Dry, rocky areas in coniferous forests.
Origin: Native
Flowers: May-June
Penstemon procerussmall-flowered penstemon
Distribution: Widely distributed throughout Washington; Alaska south to California, east to North Dakota, Wyoming and Colorado.
Habitat: Moist forest openings at moderate elevations to rocky slopes at high elevations.
Origin: Native
Flowers: June-August
var. procerus – small-flowered penstemon
var. tolmiei – small-flowered penstemon
Penstemon pruinosusChelan beardtongue
Distribution: Chiefly on the east slope of the Cascades in Washington; British Columbia south to Washington.
Habitat: Open, rocky places from the valleys and plains to moderate elevations in the mountains, and in the scablands in Washington.
Origin: Native
Flowers: May-July
Penstemon richardsoniiRichardson's penstemon
Distribution: Chiefly east of the Cascades in Washington; southern British Columbia to Oregon.
Habitat: Cliff crevices and other dry, rocky places at low elevations.
Origin: Native
Flowers: June-August
var. richardsonii – Richardson's penstemon
Penstemon rupicolacliff beardtongue, rock penstemon
Distribution: In the Cascades of Washington; Washington south to California.
Habitat: Rock cliffs and rocky slopes at mid- to high elevations in the mountains.
Origin: Native
Flowers: May-August
Penstemon rydbergiiRydberg's beardtongue
Distribution: Occurring east of the Cascades in Washington; Washington south to the Sierras of California, east to northern Wyoming and northern New Mexico.
Habitat: Meadows and moist, open slopes, occasionally on drier slopes with sagebrush, chiefly in the foothills and at moderate elevations in the mountains.
Origin: Native
Flowers: May-July
Penstemon serrulatusCascade beardtongue, coast penstemon
Distribution: Occurring in the Olympics and Cascades mountains in Washington; Alaska south to Oregon.
Habitat: Moist places at mid- to high elevations in the Cascades, but at lower elevations to the west
Origin: Native
Flowers: June-August
Penstemon speciosusroyal beardtongue, showy penstemon
Distribution: East of the Cascades in Washington; Washington south to California, east to Nevada and Utah.
Habitat: Dry, open or sparsely wooded areas, often with sagebrush, juniper or ponderosa pine, mostly in the lowlands and foothills.
Origin: Native
Flowers: May-July
Penstemon subserratusfine-tooth beardtongue
Origin: Native
Flowers: May - July
Penstemon triphylluswhorled beardtongue
Distribution: Occurring chiefly in the southeastern area of Washington; Southeast Washington south to adjacent Oregon and east to adjacent Idaho.
Habitat: Cliff crevices and dry, rocky banks and slopes at low elevations.
Origin: Native
Flowers: May-July
Penstemon venustuselegant beardtongue, Blue Mountain penstemon
Distribution: Occurring east of the Cascades in Washington, especially in the Blue Mountains area; Washington south to California and Utah, east to Idaho.
Habitat: Open, rocky slopes, from the foothills to moderate elevations in the mountains.
Origin: Native
Flowers: May-August
Penstemon washingtonensisWashington beardtongue
Distribution: Endemic to Chelan and Okanogan counties, Washington.
Habitat: From open slopes and flats at moderate elevations to alpine meadows.
Origin: Native
Flowers: July-August
Penstemon wilcoxiiWilcox's beardtongue
Distribution: East of the Cascades in Washington; Washington south to Oregon, east to Montana.
Habitat: Open or often wooded, sometimes in rocky places, from the foothills to moderate elevations in the mountains.
Origin: Native
Flowers: May-July
Pentaglottis sempervirensgreen alkanet
Distribution: Occurring in lowland western Washington; British Columbia south to California.
Habitat: Disturbed soil in shaded areas.
Origin: Introduced from sw Europe
Flowers: April-July
Pentagramma triangularisgold fern, gold-back fern
Distribution: Mostly west of the Cascades, Vancouver Island, B.C., to Baja California, east to Arizona, and in the Blue Mountains of Washington
Habitat: Rock crevices and open, rocky slopes in the valleys and foothills
Origin: Native
Penthorum sedoidesditch stonecrop
Origin: Introduced
Perideridia bolanderiBolander's yampah
Distribution: Northeast Oregon and adjacent Idaho, south through eastern Oregon and western Idaho to Nevada and Utah.
Habitat: Dry, open, often rocky hillsides, ridges and dry washes in the foothills and high plains.
Origin: Native
Flowers: July - August
Perideridia montanaGairdner's yampah
Distribution: Occurring on both sides of the Cascades crest in Washington; southern British Colombia to southern California, east to Saskatchewan, South Dakota and New Mexico.
Habitat: Woodlands and vernally wet meadows.
Origin: Native
Flowers: July-September
Perideridia oreganasquaw-potato
Distribution: Western Washington to northern California, in and west of the Cascades.
Habitat: Moist to dry meadows and open slopes or flats, from the valleys to well up in the mountains.
Origin: Native
Flowers: June - August
Perilla frutescens
Origin: Introduced
Peritoma luteayellow bee plant
Distribution: East of the Cascades in Washington; widely distributed throughout western U.S.
Habitat: Sagebrush desert to Ponderosa pine forests.
Origin: Native
Flowers: June-September
Peritoma serrulataguaco Rocky Mountain bee-plant, Rocky Mountain beeplant, guaco, stinkweed
Distribution: East of the Cascades in Washington; widely distributed throughout North America except Alaska and southeastern U.S.
Habitat: Sagebrush deserts and Ponderosa pine forest openings.
Origin: Native
Flowers: June-August
Perovskia atriplicifolia
Origin: Introduced
Persicaria amphibiawater smartweed
Distribution: Widely distributed throughout Washington; distributed throughout North America and worldwide.
Habitat: Wet soil, often partially submersed.
Origin: Native
Flowers: July-October
Persicaria hydropipersmartweed, mild water-pepper
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
Persicaria hydropiperoideswater pepper, swamp smartweed
Distribution: Chiefly west of the Cascades in Washington; British Columbia south to Mexico and South America, east across North America to the Atlantic coast.
Habitat: Moist to swampy areas, often growing in mud, from the lowlands to the lower mountain valleys.
Origin: Native
Flowers: July-September
Persicaria lapathifoliadock-leaf smartweed, pale smartweed, willow weed
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
Persicaria maculosaheartweed, lady's-thumb, spotted lady's-thumb, redshank
Distribution: Occurring throughout much of Washington; widely distributed throughout North America.
Habitat: A weedy species, usually on moist, cultivated or otherwise disturbed soil.
Origin: Introduced
Flowers: March-September
Persicaria nepalensisNepal knotweed
Origin: Introduced
Persicaria orientalisKiss-me-over-the-garden-gate, princess-feather
Origin: Introduced
Persicaria punctatadotted knotweed, dotted smartweed, water smartweed
Distribution: Occurring mostly in south-central Washington; British Columbia south to California, east to the Atlantic Coast.
Habitat: Lake and pond shores, marshes, and wet forests.
Origin: Native
Flowers: June-September
Persicaria wallichiigarden knotweed, Himalayan knotweed
Distribution: Occurring west of the Cascades crest in Washington; British Columbia south to California; also in eastern North America.
Habitat: Waste areas, roadsides, and other disturbed areas where often where somewhat moist.
Origin: Introduced from eastern Asia
Flowers: July-October
Petasites frigidus
Distribution: Occurring in forested and mountainous areas throughout Washington; Alaska south to California, east across the northern half of North America to the Atlantic Coast; circumboreal.
Habitat: Wet meadows and damp woods.
Origin: Native
Flowers: March-July
var. frigidus – alpine butterbur, arctic butterbur, sweet coltsfoot
var. palmatus – western coltsfoot
var. sagittatus – arrowhead coltsfoot, arrowhead sweet coltsfoot, arrowleaf coltsfoot
var. ×vitifolius – hybrid coltsfoot, Wenatchee coltsfoot
Petasites japonicusJapanese coltsfoot
Distribution: Sparingly introduced in Washington
Habitat: Escaped from cultivation
Origin: Introduced
var. giganteus – Japanese sweet coltsfoot
var. japonicus – Japanese sweet coltsfoot
Petrophytum caespitosumRocky Mountain rockmat
Origin: Native
ssp. caespitosum – Rocky Mountain rockmat
Petrophytum cinerascensChelan rockmat
Distribution: Endemic to Columbia River region of central Washington.
Habitat: Basaltic cliffs.
Origin: Native
Flowers: June-August
Petrophytum hendersoniiOlympic Mountain rockmat
Distribution: Endemic to (only occurring in) the Olympic Mountains of Washington.
Habitat: Rocky cliffs and talus slopes at mid- to high elevations.
Origin: Native
Flowers: July-September
Petroselinum crispumparsely
Distribution: Occurring west of the Cascades crest in Washington at low elevations;
Origin: Introduced from Europe
Phacelia bolanderiBolander's phacelia, Bolander's scorpion-weed
Distribution: Disjunct in Pacific and Wahkiakum counties, Washington; Coos Bay, Oregon south along the coast to Sonoma County, California.
Habitat: Mostly on open, often unstable slopes at low elevations.
Origin: Native
Flowers: June-July
Phacelia frankliniiFranklin's scorpion-weed
Origin: Native
Flowers: June - July
Phacelia glanduliferasticky phacelia, glandular-hair scorpion-weed
Distribution: Occurring east of the Cascades crest in Washington; Washington south to California, east to Idaho, Nevada, Utah, and Wyoming.
Habitat: Open areas in sagebrush-steppe habitat.
Origin: Native
Flowers: June
Phacelia hastatasilverleaf phacelia, whiteleaf phacelia
Distribution: Both sides of the Cascades in Washington; British Columbia to California, east to the Dakotas and Nebraska.
Habitat: Dry, open, often sandy areas, low to high elevations.
Origin: Native
Flowers: May-August
var. compacta – silverleaf phacelia, whiteleaf phacelia
var. hastata – silverleaf phacelia, whiteleaf phacelia
var. leptosepala – narrow-sepal scorpion-weed
Phacelia heterophyllavarileaf phacelia, virgate phacelia
Distribution: Occurring on both sides of the Cascades in Washington; British Columbia south to California, east to Montana and New Mexico.
Habitat: Widespread in dry, open places from the foothills to mid-elevations in the mountains.
Origin: Native
Flowers: May-July
var. heterophylla – varileaf phacelia
var. virgata – varileaf phacelia
Phacelia humilislow phacelia
Distribution: Okanogan to Yakima counties in central Washington; south through Oregon to east slope of the Sierra in California and Nevada.
Habitat: Moist to moderately dry soil at low to mid-elevations in the mountains.
Origin: Native
Flowers: May-July
var. humilis – low phacelia
Phacelia lentasticky scorpion-weed
Distribution: Endemic to Columbia Basin of central Washington.
Habitat: Open rocky habitats, talus, rocky outcrops.
Origin: Native
Flowers: April-June
Phacelia linearisthread-leaf scorpion-weed
Distribution: Chiefly east of the Cascades in Washington; British Columbia to California, east to Utah.
Habitat: Common in dry, open places in the foothills and plains to moderate elevations in the mountains
Origin: Native
Flowers: April-June
Phacelia minutissimaleast phacelia, dwarf scorpion-weed
Distribution: Uncommon; known from the type locality in Idaho, the Wallowa Mountains of Oregon, Elko County, Nevada, and Kittitas County, Washington.
Habitat: Moderate elevations in the mountains.
Origin: Native
Flowers: July
Phacelia mutabilischangeable scorpion-weed
Distribution: Occurring in scattered locations in Washington; Washington south to California, east to Nevada.
Habitat: Open areas at middle elevations.
Origin: Native
Flowers: May-July
Phacelia nemoralisshade phacelia, woodland phacelia
Distribution: Chiefly from the coast to the lower western slopes of the Cascades in Washington; south to California.
Habitat: Thickets and woodlands, usually in fairly dry and shady areas, at low elevations.
Origin: Native
Flowers: April-July
var. oregonensis – woodland phacelia
Phacelia proceratall scorpion-weed
Distribution: Chiefly in the East Cascades Mountains of Washington; south to the northern Sierra and Coast Ranges of California; also in the Blue Mountains of Oregon and adjacent Idaho.
Habitat: Meadows and lightly wooded slopes at moderate elevations in the mountains.
Origin: Native
Flowers: June-August
Phacelia ramosissimabranched phacelia
Distribution: East of the Cascades in central Washington, sout to California, east to southwest Idaho and Arizona.
Habitat: Dry, open places in the plains and foothills, commonly on basaltic talus, ledges and cliffs.
Origin: Native
Flowers: May - August
var. ramosissima – branched phacelia
Phacelia sericeasilky phacelia
Distribution: In the Olympic and Cascade mountains of Washington; Alaska south to California, east to Montana and New Mexico.
Habitat: Open, often rocky areas, mid- to high elevations in the mountains.
Origin: Native
Flowers: June-August
var. sericea – silky phacelia
Phacelia tetrameradwarf phacelia, four-part yellow scorpion-weed
Origin: Native
Flowers: May - June
Phalaris arundinaceareed canary grass
Distribution: Widely distributed throughout Washington; widely distributed throughout North America.
Habitat: Wet places, usually where disturbed, especially along roads, streambanks, and open fields.
Origin: Introduced
Flowers: June-July
Phalaris canariensiscommon canary grass
Origin: Introduced
Flowers: June - August
Phalaris paradoxaMediterranean canary grass
Origin: Introduced
Flowers: June - August
Phegopteris connectilisnarrow beech fern, northern fern
Distribution: Circumboreal; south in the Pacific Northwest to northern Oregon and the Selkirk Mountains
Habitat: Cliff crevices and moist banks in wooded regions
Origin: Native
Phemeranthus sediformisOkanogan fameflower
Distribution: Occurring east of the Cascades crest in north-central Washington; southern British Columbia south to northern Washington.
Habitat: Rocky, exposed slopes and ledges in the lower mountains.
Origin: Native
Flowers: May-July
Phemeranthus spinescensspinescent fameflower, spiny fameflower
Distribution: Occurring east of the Cascades crest in Washington; Washington south to Oregon.
Habitat: Rocky, basaltic outcrops and scabland in sagebrush.
Origin: Native
Flowers: May-September
Philadelphus lewisiiColumbian mock orange, Lewis' mock orange, Piper's mock orange, Zeller's mock orange
Distribution: Widely distributed throughout Washington; British Columbia south to California, east to Montana.
Habitat: Various habitats, dry to moist, sea level to 7000 feet (on the east slopes of the Cascades).
Origin: Native
Flowers: May-July
Phleum alpinummountain Timothy
Distribution: Alaska east to Newfoundland, south in the subalpine regions of the mountains in most of western United States.
Habitat: Streambanks and meadows at higher elevations.
Origin: Native
Flowers: Late June - August
Phleum pratenseTimothy
Distribution: Both sides of the Cascades in Washington; throughout North America.
Habitat: Disturbed areas, especially moist, open meadows, from coast to midmontane.
Origin: Introduced
Flowers: May-July
ssp. pratense – common Timothy
Phlox caespitosaclumped phlox, clustered phlox, stiff phlox, tufted phlox
Distribution: East of the Cascades, British Columbia to California, east to Colorado
Habitat: Primarily in and near Ponderosa pine forest.
Origin: Native
Flowers: April - June
Phlox colubrinaSnake River phlox
Origin: Native
Flowers: April - June
Phlox diffusaspreading phlox
Distribution: Widely distributed throughout most of Washington; British Columbia south to California, east to the Rocky Mountains and into the Great Plains in the north.
Habitat: Open, often rocky areas, mid- to high elevations in the mountains.
Origin: Native
Flowers: May-August
Phlox hendersoniiHenderson's phlox
Distribution: In Washington known from the Olympic Mountains and central Cascades east of the crest; Washington south to Oregon.
Habitat: Open, often rocky areas, mid- to high elevations in the mountains.
Origin: Native
Flowers: July-August
Phlox hoodiiHood's phlox
Distribution: Occurring east of the Cascades crest in Washington; Alaska south to California, east to the Rocky Mountains and Great Plains in the north.
Habitat: Dry, open places in the plains and foothills, often in lithosol, occasionally to moderate elevations in the mountains.
Origin: Native
Flowers: April-June
ssp. canescens – Hood's phlox
Phlox longifolialong-leaf phlox
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia south to California, east to the Rocky Mountains.
Habitat: Dry, open, rocky places, from the lowlands to moderate or occasionally high elevations in the mountains.
Origin: Native
Flowers: April-June
Phlox mollissoft phlox
Origin: Native
Phlox multifloramany-flowered phlox
Origin: Native
Phlox solivagayeti phlox
Origin: Native
Phlox speciosashowy phlox
Distribution: Occurring east of the Cascades crest in Washington; British Columbia south to California, east to Idaho, Montana, Nevada, Arizona, and New Mexico.
Habitat: Shrub-steppe, often with sagebrush, and in ponderosa pine areas.
Origin: Native
Flowers: April-June
Phlox viscidasticky phlox
Distribution: Occurring east of the Cascades crest in Washington; Washington south to Arizona, east to Idaho, Utah, and New Mexico.
Habitat: Open areas in grasslands and ponderosa pine forest.
Origin: Native
Flowers: April-June
Phoenicaulis cheiranthoidesdaggerpod
Distribution: East of the Cascades in Washington; Washington to California, east to Idaho and Nevada.
Habitat: Shrub-steppe and open Ponderosa pine forests.
Origin: Native
Flowers: April-June
Photinia davidianaChinese redtip, stranvaesia
Origin: Introduced from China
Photinia villosaoriental redtip
Origin: Introduced from China
Phragmites australiscommon reed
Distribution: In scattered locations throughout many areas of Washington; widely distributed throughout North America; circumboreal.
Habitat: Disturbed areas, including roadsides, often where wet or seasonally moist.
Origin: Native
Flowers: July-September
ssp. americanus – common reed
ssp. australis – common reed
Phyllodoce empetriformispink mountain-heath
Distribution: Alaska to California, east to Alberta and Wyoming; in the Olympics and Cascades in Washington
Habitat: Rocky sites in high coniferous forests to alpine meadows
Origin: Native
Flowers: June - August
Phyllodoce glanduliflorayellow mountain-heath
Distribution: Occurring in mountainous areas across Washington; Alaska south to Oregon, east to Wyoming.
Habitat: Rocky sites in high coniferous forests to alpine meadows and seeps.
Origin: Native
Flowers: July-September
Phyllodoce ×intermedia
Distribution: Occasional where Phylodoce empetriformis and P. glandulosum are found growing in the same area, in the Cascades and Rocky Mountains.
Habitat: High elevations in the mountains.
Origin: Native
Flowers: July - August
Phyllospadix scouleriScouler's surf-grass
Distribution: Occurring along the coast of Washington where rocky; Alaska south to California.
Habitat: Intertidal and sub-tidal levels.
Origin: Native
Flowers: May-August
Phyllospadix serrulatustoothed surf-grass
Origin: Native
Phyllospadix torreyiTorrey's surf-grass
Origin: Native
Flowers: May - September
Physalis grisealow hairy ground cherry, strawberry-tomato
Origin: Introduced from eastern North America
Flowers: July - September
Physalis heterophyllaground cherry
Origin: Introduced
Physalis longifoliaground-cherry, long-leaved ground-cherry, wild tomatillo
Distribution: Occurring chiefly east of the Cascades in Washington; occurring throughout much of North America.
Habitat: Weed of cultivated fields and waste places.
Origin: Introduced
Flowers: June-September
Physalis philadelphicatomatillo
Distribution: In scattered localities in lowland western Washington; occurring across much of North America.
Habitat: Disturbed areas at low elevations near towns and cities.
Origin: Introduced from Mexico
Flowers: June-September
Physaria alpestrisalpine twinpod, Washington twinpod
Distribution: East side of the Cascades in Washington, Chelan County to Mt. Adams.
Habitat: Open rocky areas, mid- to high elevations in the mountains.
Origin: Native
Flowers: April-July
Physaria didymocarpacommon twinpod
Origin: Native
Flowers: June - August
ssp. didymocarpa – common twinpod
Physaria douglasiiColumbia bladderpod, Douglas' bladderpod
Distribution: British Columbia to northern Oregon, east to Idaho; chiefly near the Columbia and Snake Rivers
Habitat: Common in sagebrush desert, especially near or in juniper or ponderosa pine woodlands.
Origin: Native
Flowers: March-July
ssp. douglasii – Douglas's bladderpod
ssp. tuplashensis – white bluffs bladderpod, White Bluffs bladderpod
Physaria geyeriGeyer's twinpod
Distribution: Occurring in eastern portion of Washington; Washington east to Idaho and Montana.
Habitat: Gravelly stream banks and hillsides.
Origin: Native
Flowers: May-July
ssp. geyeri – double bladderpod, Geyer's twinpod bladderpod, Geyer's twinpod
Physaria occidentaliswestern bladderpod
Distribution: Occurring east of the Cascades in Washington; Washington south to California, east to Idaho and Nevada.
Habitat: Open, rocky slopes at low to moderate elevations.
Origin: Native
Flowers: April-June
ssp. occidentalis – western bladderpod
Physaria oregonaOregon twinpod
Distribution: Occurring in southeastern corner of Washington; Washington east to Idaho, south to Oregon.
Habitat: Dry areas including rocky slopes, gravel banks, and stream shores.
Origin: Native
Flowers: April-June
Physocarpus capitatusPacific ninebark
Distribution: Occurring on both sides of the Cascades crest in Washington, but found chiefly on the west side; Alaska south to California, east to Alberta and Idaho.
Habitat: Moist woods and swamps in the lower mountains.
Origin: Native
Flowers: May-June
Physocarpus malvaceusmallow ninebark, mallow-leaf ninebark
Distribution: East of the Cascades, British Columbia to Oregon, east to Alberta and Montana, and south to Utah and Wyoming
Habitat: Canyons and hillsides, grasslands, ponderosa pine and Douglas fir forests
Origin: Native
Flowers: June - July
Physostegia parviflorapurple dragonhead, western false dragonhead
Distribution: East of the Cascade summits, British Columbia south through Washington to the Columbia Gorge, where west to Portland, Oregon; east to Idaho and North Dakota.
Habitat: Shores of strams and lakes, marshes, and other low, wet places in the valleys and foothills.
Origin: Native
Flowers: July - September
Phyteuma scorzonerifolium
Distribution: Known in Washington from a single population in King County, WA.
Habitat: Disturbed areas.
Origin: Introduced
Flowers: July-August
Phytolacca americanapigeonberry, pokeberry, pokeweed
Distribution: A few scattered locations across Washington.
Habitat: Roadsides, pastures, clearings, disturbed areas.
Origin: Introduced
Flowers: June-August
var. americana – pigeonberry, pokeberry, pokeweed
Picea ×albertianainterior spruce
Origin: Native
Picea engelmanniiEngelmann's spruce
Distribution: British Columbia south through the Cascades of Washington and Oregon to Shasta County, California, east to Montana and New Mexico.
Habitat: Moderate to high elevations in the mountains, mostly where somewhat moist.
Origin: Native
Cones: New cones from June-August
var. engelmannii – Engelmann spruce
Picea sitchensisSitka spruce
Distribution: West of the Cascades, Alaska to California
Habitat: Along the coast, from sea level up to about 2,000 feet in moist valleys
Origin: Native
Cones: May
Picris hieracioideshawkweed oxtongue
Origin: Introduced from Europe
Pilularia americanaAmerican pillwort
Origin: Native
Pimpinella saxifragaburnet-saxifrage
Origin: Introduced
Flowers: July - September
ssp. nigra – burnet-saxifrage
Pinguicula vulgariscommon butterwort
Distribution: Widely distributed on both sides of the Cascades in Washington; circumboreal, in America extending south to southwest Oregon, east to Montana and New York.
Habitat: Bogs and wet soil in the mountains.
Origin: Native
Flowers: July-August
ssp. macroceras – common butterwort
Pinus albicauliswhite-bark pine
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Wyoming and Montana.
Habitat: Generally near timberline, preferring south-facing slopes.
Origin: Native
Cones: June-July
Pinus contorta
Distribution: Alaska south into Oregon, east to Alberta and South Dakota, and in the Rocky Mountain states
Habitat: Dry montane forests, rocky balds, coastal bluffs and sand dunes, and sphagnum bogs.
Origin: Native
Cones: April - June
var. contorta – shore pine
var. latifolia – lodgepole pine
var. murrayana – Sierra lodgepole pine
Pinus monticolawestern white pine
Distribution: British Columbia to California, east to Utah and Montana; in the Washington Olympics
Habitat: Moist valleys and drier slopes, near sea level to mid-elevations in the mountains
Origin: Native
Cones: May - June
Pinus pinaster
Origin: Introduced
Pinus ponderosablackjack pine, bull pine, ponderosa pine, western yellow pine
Distribution: Mostly east of the Cascades, British Columbia to Baja California, east to the Dakotas and Texas; in a few localities in the Puget Trough, Washington, and the Willamette Valley Oregon
Habitat: Mostly dry areas in open forests at low to moderate elevations
Origin: Native
Cones: May - June
Piptatheropsis exigualittle mountain-ricegrass
Distribution: Occurring chiefly east of the Cascades crest in Washington; southern British Columbia, south east of the Cascade crest to Oregon, east to Montana and Colorado.
Habitat: Sandy to rocky soil, mountain meadows to subalpine and alpine ridges and slopes.
Origin: Native
Flowers: June-August
Pisum sativumgarden pea
Origin: Introduced
Pityopus californicusCalifornia pinefoot
Origin: Native
Flowers: June - July
Plagiobothrys cognatus
Origin: Native
Plagiobothrys cusickiimatted popcorn flower
Origin: Native
Plagiobothrys figuratusfragrant plagiobothrys
Distribution: Occurring chiefly west of the Cascades and in the Columbia River Gorge in Washington; British Columbia south to Oregon.
Habitat: Nonalkaline meadows, low ground, and moist fields.
Origin: Native
Flowers: May-July
Plagiobothrys figuratus var. figuratusfragrant popcorn flower
Origin: Native
Plagiobothrys hispidulusharsh plagiobothrys
Origin: Native
Plagiobothrys leptocladusalkali popcorn flower, slender branched popcorn flower
Distribution: East of the Cascades in Oregon, south to Baja California, east to northern Utah and the Snake River plains in Idaho.
Habitat: Moist clay flats and beds of drying pools; tolerant of alkali.
Origin: Native
Flowers: April - July
Plagiobothrys nothofulvusrusty popcorn flower
Distribution: Common in the east end of the Columbia River Gorge in Washington; Oregon south to northern Baja California and east to Nevada.
Habitat: Open slopes, fields and roadsides.
Origin: Native
Flowers: March-May
Plagiobothrys scouleriScouler's popcorn flower
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska south to California, east to Wisconsin and New Mexico.
Habitat: Moist areas, foothills to mid-elevations in the mountains, seldom in alkaline areas.
Origin: Native
Flowers: May-August
Plagiobothrys tenellusPacific popcorn flower, slender popcorn flower
Distribution: Occurring chiefly east of the Cascades crest in Washington; southern British Columbia to Baja California, east to Idaho and Nevada.
Habitat: Dry, open places at low elevations.
Origin: Native
Flowers: April-June
Plantago arenariasand plantain
Distribution: Scattered locations west of the Cascades in Washington; British Columbia south to California; upper central and eastern North America.
Habitat: A weed of waste places, sandy areas, roadsides, and along railroad tracks.
Origin: Introduced
Flowers: June-October
Plantago coronopusbuck-horn plantain
Distribution: West of the Cascades along the coast in Washington; British Columbia south to California; scattered locations in central and eastern North America.
Habitat: Occasional at low elevations along the coast in sandy or disturbed areas.
Origin: Introduced
Flowers: May-October
Plantago elongataslender plantain
Distribution: West of the Cascades in Washington, often along the coast; British Columbia south to California, east to Minnesota and Texas.
Habitat: Moist, somewhat saline areas.
Origin: Native
Flowers: April-June
Plantago lanceolataEnglish plantain
Distribution: Widely distributed throughout Washington; a cosmopolitan weed distributed widely throughout North America.
Habitat: Roadsides, fields and other disturbed, open areas.
Origin: Introduced from Europe
Flowers: April-August
Plantago macrocarpaAlaska plantain
Distribution: Occurring along the outer coast in Washington; Alaska south to Oregon.
Habitat: Coastal wetlands.
Origin: Native
Flowers: May-June
Plantago majornippleseed, common plantain, great plantain
Distribution: Widely distributed throughout Washington; a cosmopolitan weed widely distributed throughout North America.
Habitat: Roadsides, fields and other disturbed, open areas.
Origin: Introduced from Europe
Flowers: April-August
Plantago maritimasea plantain, seaside plantain
Distribution: West of the Cascades in Washington along the coast; British Columbia south to California.
Habitat: Salt marshes, bluffs and cliffs along the coast.
Origin: Native
Flowers: May-July
Plantago patagonicawoolly plantain
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia south to California, east to Texas.
Habitat: Dry, open places in the foothills and plains.
Origin: Native
Flowers: April-June
Plantago pusilladwarf plantain
Origin: Introduced from eastern North America
Plantago subnudaMexican plantain, tall coastal plantain
Distribution: West of the Cascades in Washington in the southwestern portion of the state; Washington south to California.
Habitat: Tidal flats and coastal bluffs.
Origin: Native
Flowers: May-September
Platanthera aquiloniseagle rein orchid, Sheviak's bog orchid
Distribution: Known only from Steven County in Washington; Alaska south to Oregon, east across the northern half of North America to the Atlantic Coast;
Habitat: Wet meadows from montane to subalpine.
Origin: Native
Flowers: June-August
Platanthera chorisianachoriso bog orchid
Distribution: Known only from Snohomish County in Washington; Aleutian Islands south the Vancouver Island, British Columbia, and in Snohomish County, Washington.
Habitat: Moist areas, especially at the edges of streams and bogs.
Origin: Native
Flowers: July-August
Platanthera dilatatascent bottle, bog candle, boreal bog orchid, white orchid, white rein orchid
Distribution: Widely distributed through the mountainous and forested areas of Washington; Alaska south to California, east to the Rocky Mountains; also in northeastern in North America.
Habitat: Wet meadows, forest openings, and streambanks from low elevations to the subalpine.
Origin: Native
Flowers: June-September
var. albiflora – white bog orchid
var. dilatata – white bog orchid
var. leucostachys – white bog orchid
Platanthera eleganshillside rein orchid, elegant rein-orchid
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia south to California, east to Idaho and Montana.
Habitat: Mostly in dry, open woods and hills where moist in spring.
Origin: Native
Flowers: June-September
ssp. elegans – elegant rein orchid, hillside rein orchid
Platanthera elongatadense orchid, dense-flower rein orchid
Distribution: Occurring on both sides of the Cascades in Washington; British Columbia south to California, east to Idaho and Montana.
Habitat: Dry, open forest from low to middle elevations.
Origin: Native
Flowers: July-September
Platanthera ephemeranthawhite-lip rein orchid
Distribution: West of the Cascades in Washington and Columbia River Gorge; Alaska to California.
Habitat: Moist coniferous forest at low elevations.
Origin: Native
Flowers: May-June
Platanthera huronensisnorthern green bog orchid
Distribution: Occurring chiefly east of the Cascades crest in Washington; Alaska south to Oregon, east to the Rocky Mountains; also from north-central to northeastern North America.
Habitat: Moist to boggy areas, often on limestone, low to mid-elevations.
Origin: Native
Flowers: June-August
Platanthera obtusatasmall northern bog-orchid, blunt-leaf rein-orchid, one-leaf rein-orchid
Distribution: Scattered locations on both sides of the Cascades in Washington; Alaska to Oregon, east to Montana and Colorado, across Canada to Newfoundland.
Habitat: Damp to wet forests at mid-elevations in the mountains.
Origin: Native
Flowers: June-July
ssp. obtusata – blunt-leaf rein orchid, one-leaf rein orchid, small northern bog orchid
Platanthera orbiculatalarge round-leaf orchid
Distribution: Alaska to Newfoundland, south on both sides of the Cascades to Oregon, Idaho and northwest Montana; east to Minnisota, Indiana and Georgia.
Habitat: Moist, mossy forests.
Origin: Native
Flowers: June - August
Platanthera sparsifloracanyon bog orchid
Origin: Native
Platanthera strictacanyon bog orchid, needle-spur green orchid, slender bog orchid
Distribution: Widely distributed throughout Washington; Alaska south to California, east to Montana and New Mexico.
Habitat: Wet meadows, swamps and coniferous forests, low to mid-elevations.
Origin: Native
Flowers: June-August
Platanthera transversaroyal rein orchid
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia south to California.
Habitat: Forest understory from low to middle elevations.
Origin: Native
Flowers: May-August
Platanthera unalascensisAlaska rein orchid
Distribution: Widely distributed throughout Washington; Alaska south to California, east to Quebec and Colorado.
Habitat: Dry, open woods and gravelly streambanks, low to mid-elevations in the mountains.
Origin: Native
Flowers: June-August
Platanus occidentalisAmerican plane-tree, sycamore
Distribution: Occurring along the shores of the Columbia River in central Washington; common and native east of the Rocky Mountains, often introduced in western United States.
Habitat: Near streams and lakes, in moist ravines.
Origin: Introduced
Flowers: April-May
Plectritis brachystemonshortspur white plectritis
Distribution: In Washington occurring west of the Cascades crest and in the Columbia River Gorge; southern British Columbia south to California.
Habitat: Coastal bluffs, lowland prairies, balds at low elevations in the mountains.
Origin: Native
Flowers: April-June
Plectritis ciliosalong-spurred plectritis
Distribution: Klickitat County, Washington, south through western Oregon to California.
Habitat: Vernally moist, open slopes and meadows.
Origin: Native
Flowers: April - May
Plectritis congestasea blush, rosy plectritis
Distribution: In Washington occurring west of the Cascades crest and in the Columbia River Gorge; Vancouver Island south to California.
Habitat: Open, vernally moist meadows and slopes, sea level to moderate elevations in the moutains.
Origin: Native
Flowers: April-June
Plectritis macroceralong-horn plectritis, white plectritis
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia south to California, east to the Rocky Mountains.
Habitat: Vernally moist, open areas; common in shrub-steppe
Origin: Native
Flowers: March-June
Pleiacanthus spinosusthorny skeletonweed
Origin: Introduced?
Pleuricospora fimbriolatafringed pinesap
Distribution: Western slope of the Cascades and the Olympic Mountains in Washington; Washington south to California.
Habitat: Uncommon in coniferous forests at mid-elevations.
Origin: Native
Flowers: June-August
Pleuropogon refractusnodding false semaphore grass
Distribution: Southern British Columbia south in both the Southern British Columbia south in both the Olympics and Cascades of Washington, and the Cascades and coastal mountain of Oregon, to Mendocino County, California.
Habitat: Bogs, stream banks, swampy meadows,and moist, shaded woods, from near sea level toabout 5000 feet elevation in the mountains.
Origin: Native
Flowers: May - August
Poa alpinaalpine bluegrass
Origin: Native
ssp. alpina – alpine blue grass
Poa annuaannual blue grass
Distribution: Common weed throughout the Pacific Northwest.
Habitat: Lawns, gardens, roadsides, and waste ground to open woods.
Origin: Introduced
Flowers: March - August
Poa arcticaarctic bluegrass
Origin: Native
Poa bolanderiBolander's blue grass
Origin: Native
Flowers: July - August
Poa bulbosabulbous bluegrass
Distribution: Both sides of the Cascades in Washington; throughout most of western North America, more scattered in central and eastern North America.
Habitat: Disturbed areas from the coast to midmontane.
Origin: Introduced
Flowers: March-June
ssp. vivipara – bulbous blue grass
Poa compressaflat-stem blue grass
Distribution: Alaska east to Newfoundland, south to most of the United States; common in the Pacific Northwest.
Habitat: Waste ground, roadsides, and gardens to open woods and meadows, usually where moist.
Origin: Introduced
Flowers: June - August
Poa confiniscoastline blue grass
Distribution: VAncouver Island, British Columbia, south along the coast to San Francisco, California.
Habitat: Coastal sand dunes.
Origin: Native
Flowers: May - June
Poa curtifolialittle mountain blue grass
Origin: Native
Flowers: June - August
Poa cusickiiCusick's bluegrass
Distribution: British Columbia south in the Olympics and Cascades to California, east to Saskatchewan and Colorado.
Habitat: Sagebrush plains to alpine meadows and ridges.
Origin: Native
Flowers: June - August
ssp. cusickii – Cusick's bluegrass
ssp. epilis – skyline bluegrass
ssp. pallida – Cusick's bluegrass
ssp. purpurascens – Cusick's bluegrass
Poa fendlerianamuttongrass
Origin: Native
Flowers: May - August
ssp. longiligula – muttongrass
Poa glauca
Origin: Native
ssp. rupicola – timberline bluegrass
Poa howelliiHowell's blue grass
Origin: Native
Flowers: April - June
Poa infirmaweak bluegrass
Origin: Introduced
Poa interiorinterior bluegrass, woods blue grass
Origin: Native
Poa laxifloraloose-flower blue grass
Distribution: Southern Alaska south to the Olympic Peninsula of Washington and Multnomah, Clackamus and Benton Counties, Oregon.
Habitat: Moist woods to rocky, open slopes, from near sea level to lower elevations in the mountains.
Origin: Native
Flowers: June
Poa leibergiiLeiberg's blue grass
Origin: Native
Flowers: Late March - May
Poa leptocomamarsh blue grass
Origin: Native
Flowers: Late June - August
Poa lettermaniiLetterman's blue grass
Origin: Native
Flowers: August
Poa macranthasand-dune blue grass
Distribution: Southern Vancouver Island and the islands of Puget Sound, south along the coast to Mendocino County, California.
Habitat: Chiefly on sand dunes.
Origin: Native
Flowers: April - July
Poa marcidawithered blue grass
Origin: Native
Flowers: June - July
Poa ×multnomae
Origin: Native
Poa nemoraliswoodland bluegrass
Origin: Introduced
Flowers: May - August
Poa nervosaHooker's blue grass
Origin: Native
Flowers: April - August
Poa palustrisfowl blue grass
Distribution: Introduced and widely distributed through Alaska and Canada, south to northern California and Virginia.
Habitat: Sea level to open meadows and forested areas in the mountains, always where moist.
Origin: Introduced
Flowers: May - August
Poa paucispiculaAlaska blue grass
Origin: Native
Flowers: Late June - August
Poa pratensisKentucky bluegrass
Distribution: Throughout Washington; common throughout temperate world.
Habitat: Moist, distrurbed areas at from the coast to middle elevations.
Origin: Both native and introduced
Flowers: April - October
ssp. pratensis – Kentucky blue grass
Poa secunda
Distribution: Widely distributed throughout Washington; Alaska south to California, east to the Rocky Mountains.
Habitat: Grasslands and forest openings from sea-level to the alpine
Origin: Native
Flowers: April-July
ssp. juncifolia – alkali bluegrass, big bluegrass, Nevada bluegrass
ssp. secunda – curly blue grass
Poa stenanthanarrow-flowered bluegrass
Origin: Native
var. stenantha – narrow-flower blue grass
Poa suksdorfiiwestern blue grass
Origin: Native
Flowers: July - August
Poa trivialisrough-stalk blue grass
Origin: Introduced
Flowers: May - July
Poa unilateralissea-bluff bluegrass
Origin: Native
ssp. pachypholis – San Francisco blue grass
Poa wheeleriWheeler's blue grass
Origin: Native
Flowers: April - August
Podagrostis aequivalvisarctic bent
Origin: Native
Podagrostis humilisalpine bent, mountain bent
Origin: Native
Podagrostis thurberianaThurber's bent
Origin: Native
Polanisia dodecandra
Origin: Native
ssp. trachysperma – western clammyweed, sandyseed, clammy weed
Polemonium californicumlow Jacob's-ladder
Distribution: Cascade-Sierra region of Washington to California, east to Idaho
Habitat: Shaded or moist places, moderate to mid-elevations in the mountains
Origin: Native
Flowers: May - August
Polemonium carneumroyal Jacob's-ladder, great polemonium, salmon polemonium
Distribution: Olympic and Grays Harbor region of Washington, and Skamania County in Washington south through the Cascades to the Klamath region of Oregon and adjacent California.
Habitat: Thickets, woodlands and forest openings, from near sea level to moderate elevations in the mountains.
Origin: Native
Flowers: May - July
Polemonium eleganselegant Jacob's-ladder, elegant polemonium
Distribution: Occurring in the Olympics and Cascades mountains in Washington; British Columbia south to Washington.
Habitat: Open, often rocky areas, mid- to high elevations in the mountains.
Origin: Native
Flowers: July-September
Polemonium micranthumannual Jacob's-ladder, annual polemonium
Distribution: Chiefly east of the Cascades, British Columbia to California, east to North Dakota and Utah
Habitat: Common is open plains and foothills, often with sagebrush
Origin: Native
Flowers: March - May
Polemonium occidentalewestern polemonium
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia south to California, east to Montana and Colorado.
Habitat: Very wet places at mid-elevations in the mountains.
Origin: Native
Flowers: June-August
Polemonium pectinatumWashington Jacob's-ladder, Washington polemonium
Distribution: Known only from North Whitman County and south Spokane County, Washington.
Habitat: Moist bottom lands.
Origin: Native
Flowers: May-June
Polemonium pulcherrimumshowy polemonium
Distribution: Widely distributed in Washington; Alaska south to the Sierra Nevada of California, east to Wyoming.
Habitat: High elevations in the mountains, often in open areas above timberline.
Origin: Native
Flowers: May-August
var. pulcherrimum – showy Jacob's-ladder
Polemonium viscosumsticky Jacob's-ladder, sticky polemonium
Distribution: Know only from Okanogan County, Washington in Washington; British Columbia south to Oregon and Nevada, east to the Rocky Mountains.
Habitat: Open rocky places at high elevations in the mountains, commonly above timberline.
Origin: Native
Flowers: July-September
Polycarpon tetraphyllumfourleaf manyseed
Origin: Introduced
ssp. tetraphyllum – fourleaf manyseed
Polyctenium fremontiicombleaf
Distribution: Known only from Grant County in Washington; Washington south to California, east to Idaho and Nevada.
Habitat: Open areas in sagebrush-steppe.
Origin: Native
Flowers: April-May
Polygala vulgaris
Origin: Introduced
Polygonum achoreumBlake's knotweed
Origin: Native
Polygonum austiniaeAustin's knotweed
Distribution: Central Oregon to northeast California, east to Idaho and southcentral Montana.
Habitat: Dry to moist banks and flats, from sagebrush plains to lower mountains, often with ponderosa pine.
Origin: Native
Flowers: June - August
Polygonum aviculare
Distribution: An introduced, ubiquitous weed, found throughout the United States.
Habitat: Dry or slightly moist, disturbed soil, often where hard-packed.
Origin: Both native and introduced
Flowers: July - September
ssp. aviculare – common knotweed, yard knotweed
ssp. buxiforme – American knotweed, prairie knotweed
ssp. depressum – common knotweed, oval-leaf knotweed
ssp. neglectum – narrow-leaf knotweed
Polygonum californicumCalifornia knotweed
Origin: Native
Flowers: July - September
Polygonum douglasiiDouglas' knotweed, Douglas's knotweed
Distribution: Widely distributed throughout most of Washington; British Columbia south to California, east to the Rocky Mountains and across northern U.S./southern Canada to the Atlantic Coast.
Habitat: Common in dry to moist areas, lowlands to mid-elevations in the mountains.
Origin: Native
Flowers: June-September
Polygonum erectumerect knotweed
Origin: Native
Flowers: June - September
Polygonum fowleriFowler's knotweed
Distribution: Occurring west of the Cascades in Washington; Alaska south to California, east across northern Canada to northeastern North America.
Habitat: Coastal salt marshes.
Origin: Native
Flowers: July-November
ssp. fowleri – Fowler's knotweed
Polygonum majusPalouse knotweed, wiry knotweed
Distribution: Occurring east of the Cascades crest in Washington; British Columbia south to California, east to the Rocky Mountains.
Habitat: Dry, often semi-barren, gravelly to heavy soil, sagebrush desert to lower mountains.
Origin: Native
Flowers: May-August
Polygonum minimumleafy dwarf knotweed, zigzag knotweed
Distribution: British Columbia south in the Cascades and higher coastal mountains to the southern Sierra Navada, east in the Rockies from Montana to Colorado.
Habitat: Open or semi-barren soil in the alpine and subalpine.
Origin: Native
Flowers: July - September
Polygonum nuttalliiNuttall's knotweed
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia south to Oregon
Habitat: Prairies, grassy balds, and forest openings at low to moderate elevations.
Origin: Native
Flowers: May-July
Polygonum paronychiabeach knotweed, black knotweed
Distribution: Occurring west of the Cascades crest along the coast; Vancouver Island, B.C., south to Monterey, California.
Habitat: Coastal shorelines and sand dunes.
Origin: Native
Flowers: April-September
Polygonum parryiParry's knotweed
Origin: Native
Flowers: June - July
Polygonum patulum
Origin: Introduced
Polygonum polygaloides
Distribution: Occurring east of the Cascades crest in Washington; British Columbia south to California, east to the Rocky Mountains.
Habitat: Meadows, vernal pools and rocky ridges, lowlands to mid-elevations in the mountains.
Origin: Native
Flowers: June-August
ssp. confertiflorum – close-flowered knotweed
ssp. kelloggii – white-margin knotweed
ssp. polygaloides – Polygala knotweed
Polygonum ramosissimum
Distribution: Occurring chiefly east of the Cascades crest in Washington; widely distributed throughout North America.
Habitat: Disturbed areas, often where wet, from low to middle elevations.
Origin: Native
Flowers: July-September
ssp. prolificum – proliferous knotweed
ssp. ramosissimum – bushy knotweed
Polygonum sawatchense
Distribution: Occurring east of the Cascades crest in Washington; British Columbia south to California, east to the Great Plains.
Habitat: Dry to moist forest openings and meadows from moderate elevations to the subalpine.
Origin: Native
Flowers: June-August
ssp. oblivium – Sawatch knotweed
ssp. sawatchense – Sawatch knotweed
Polygonum spergulariiformefall knotweed, spurry knotweed
Distribution: British Columbia to California, chiefly west of the Cascades in Washington, east to southeast Washington, Idaho and Colorado.
Habitat: Gravelly, sandy or heavy dry or moist soil at low elevations.
Origin: Native
Flowers: June - September
Polypodium amorphumirregular polypody
Origin: Native
Polypodium glycyrrhizalicorice fern
Distribution: Both sides of the Cascades in Washington; Alaska south to California.
Habitat: Moist banks and rocks, tree trunks and logs, at low elevations
Origin: Native
Polypodium hesperiumwestern polypody
Distribution: Chiefly east of the Cascades, British Columbia to California, east to Montana, Colorado and New Mexico
Habitat: Moist cliffs, ledges and rock crevices, lowlands to mid-elevations in the mountains
Origin: Native
Polypodium scoulericoast, leathery polypody, Scouler's polypody
Distribution: Occurring west of the Cascades crest in Washington; British Columbia south along the coast to California.
Habitat: Cliffs and rocky outcroppings along the coast.
Origin: Native
Polypogon australisChilean rabbit's-foot grass
Origin: Introduced
Polypogon fugaxAsia Minor bluegrass
Origin: Introduced
Polypogon interruptusditch rabbit's-foot grass
Origin: Introduced
Flowers: June - August
Polypogon monspeliensisannual rabbit's-foot grass
Distribution: Occurring on both sides of the Cascades crest in Washington; widely distributed throughout much of North America.
Habitat: Wet to dry waste areas, including vernal pools where the water is brackish.
Origin: Introduced
Flowers: May-August
Polypogon viridisbeardless rabbit's-foot grass
Origin: Introduced
Flowers: June - September
Polystichum andersoniiAnderson's sword fern, Vancouver holly fern
Distribution: Southern Alaska south to northern Oregon, northern Idaho, and northwest Montana; also in the Olympic Mountains of Washington.
Habitat: Deep woods and thickets in the mountains.
Origin: Native
Polystichum californicumCalifornia sword fern
Distribution: Occurring west of the Cascades crest in Washington; southern British Columbia south to California.
Habitat: Moist forest understory at low elevations, typically in rock crevices.
Origin: Native
Polystichum imbricansimbricate sword-fern, rock sword-fern
Distribution: Cascades of central Washington south to California, and in the Olympics; sometimes on serpentine
Habitat: Dry, rocky places, open areas and open woods, at mid-elevations
Origin: Native
ssp. imbricans – imbricate fern, narrow-leaved sword fern
Polystichum kruckebergiiholly fern, Kruckeberg's sword fern fern
Distribution: Occurring in the Olympics and Cascades mountains in Washington; British Columbia south to California, east to Montana, Idaho, Nevada and Utah.
Habitat: Open slopes, typically among rocks; tolerant of serpentine.
Origin: Native
Polystichum kruckebergii × Polystichum munitumhybrid holly fern
Origin: Native
Polystichum lemmoniiLemmon's holly fern, Shasta fern
Distribution: Occurring on both sides of the Cascades in the northern half of Washington, particularly common in the Wenatchee Mountains; southern British Columbia, northern Washington, disjunct in the Wallowa Mts., and in southwestern Oregon and northern California.
Habitat: Open, rocky slopes near timberline in the mountains, chiefly on serpentine.
Origin: Native
Polystichum lemmonii × Polystichum munitumhidden sword fern
Origin: Native
Polystichum lemmonii × Polystichum scopulinumserpentine holly fern
Origin: Native
Polystichum lonchitismountain fern, northern holly fern
Distribution: Alaska to California, east to Quebec and Wyoming
Habitat: Talus slopes and cliff crevices, occasionally in coniferous forests, mid- to high elevations in the mountains
Origin: Native
Polystichum munitumcommon sword fern, western fern
Distribution: In forested areas throughout Washington; British Columbia south to California, east to Montana.
Habitat: Moist coniferous woods, in open to deep shade; from sea-level to midmontane.
Origin: Native
Spores: Spores year-round on fronds
Polystichum munitum × Polystichum scopulinumhybrid sword fern
Origin: Native
Polystichum scopulinummountain holly fern, rock sword fern
Distribution: Occurring east of the Cascades crest in Washington; British Columbia south to California, east to Montana, Idaho, Wyoming, Nevada, Utah, and Arizona.
Habitat: Open slopes, typically associated with rock outcroppings and crevices; tolerant of serpentine.
Origin: Native
Pontederia cordataPickerel-weed
Origin: Introduced
Populus albawhite poplar
Distribution: Distributed on both sides of the Cascades in Washington; widely distributed throughout North America.
Habitat: Disturbed areas often associated with urban and suburban areas, riparian zones.
Origin: Introduced from Europe
Flowers: March-May
Populus angustifolianarrow-leaved cottonwood
Origin: Native
Populus ×canescensgray poplar
Origin: Introduced from Europe
Populus deltoideseastern cottonwood
Origin: Introduced
Populus nigrablack cottonwood, lombardy poplar
Origin: Introduced
Populus tremuloidesquaking aspen
Distribution: Broadly distributed in Washington, but chiefly east of the Cascades in Washington; Alaska to California, east to Labrador and New Jersey.
Habitat: Moist areas, low to fairly high elevations in the mountains
Origin: Native
Flowers: April-June
Populus trichocarpablack cottonwood
Distribution: Occurring throughout Washington; Alaska to California, east to Alberta and Wyoming.
Habitat: Streambanks and moist woods, sea level to mid-elevations in the mountains.
Origin: Native
Flowers: April-June
Portulaca oleraceacommon purslane
Distribution: Introduced from southern Europe and widely distributed in the United States.
Habitat: Gardens, disturbed soil
Origin: Introduced from Europe
Flowers: June - Frost
Potamogeton alpinusnorthern pondweed, reddish pondweed
Origin: Native
Flowers: June - August
Potamogeton amplifoliusbroad-leaved pondweed, large-leaved pondweed
Distribution: British Columbia to Newfoundland, south to California in the west and Alabama in the eastern United States, but absent from Nevada to Texas; common west of the Cascades in Washington
Habitat: Generally in fairly deep water
Origin: Native
Flowers: June - August
Potamogeton berchtoldiiBerchtold's pondweed
Origin: Native
Flowers: Late June - August
Potamogeton crispuscurly pondweed
Distribution: Introduced in much of North America; central and western Washington, western Oregon, and California.
Habitat: Ponds and streams, often forming mats.
Origin: Introduced from Eurasia
Flowers: Late June - August
Potamogeton epihydrusribbon-leaved pondweed
Distribution: Alaska south on both sides of the Cascades to California, east to Newfoundland and northeastern United States.
Habitat: Shallow to deep water.
Origin: Native
Flowers: June - July
Potamogeton fibrillosusfibrous-stipuled pondweed
Origin: Native
Flowers: June - August
Potamogeton foliosusleafy pondweed
Distribution: British Columbia to Newfoundland, south on both sides of the Cascades to Mexico.
Habitat: Standing to moving, shallow water.
Origin: Native
Flowers: Late June - August
Potamogeton friesiiflat-stalked pondweed
Origin: Native
Flowers: July - August
Potamogeton gramineusgrassy pondweed, variable pondweed
Distribution: Alaska to Maine, south to California and New Mexico in the west and West Virginia in eastern United states
Habitat: Standing or running water
Origin: Native
Flowers: June - August
Potamogeton illinoensisillinois pondweed
Distribution: Occurring on both sides of the Cascades crest in Washington; Northwest Territories south to California, east across North America in scattered locations to the Atlantic Coast.
Habitat: Ponds and lakes, usually in rather deep, quiet water.
Origin: Native
Flowers: May-August
Potamogeton natansfloating pondweed, floating-leaved pondweed
Distribution: Alaska south on both sides of the Cascades to California, east to Arizona and northeast United States.
Habitat: In rather shallow, standing water, often where brackish.
Origin: Native
Flowers: May - August
Potamogeton nodosusloddon's pondweed, long-leaved pondweed
Distribution: British Columbia south on both sides of the Cascades to Mexico; east over most of the United States.
Habitat: Shallow to rather deep water.
Origin: Native
Flowers: June - August
Potamogeton obtusifoliusblunt-leaved pondweed
Origin: Native
Potamogeton praelonguswhite-stalked pondweed, whitestem pondweed
Distribution: Alaska south on both sides of the Cascades to California, east through Canada to Newfoundland, south to New York and Indiana.
Habitat: In the Pacific Northwest, mostly in deep water of lakes.
Origin: Native
Flowers: May - July
Potamogeton pusillussmall pondweed
Distribution: British Columbia south on both sides of the Cascades to California, east to the Atlantic.
Habitat: Shallow ponds and streams.
Origin: Native
Flowers: July - August
Potamogeton richardsoniiclasping-leaved pondweed, Richardson's pondweed
Distribution: Alaska to Maine, south to California and New Mexico in the west and Illimois in eastern United states; more common west of the Cascades in Washington
Habitat: Standing or slow-moving water
Origin: Native
Flowers: June - August
Potamogeton robbinsiifern pondweed, Robbin's pondweed
Distribution: Alaska to California, east to Montana and Colorado; Minnesota to Maine, south to Virginia in eastern United States
Habitat: Quiet water, mostly in lakes
Origin: Native
Flowers: August - September
Potamogeton strictifoliusnarrowleaf pondweed
Origin: Native
Potamogeton zosteriformiseel-grass pondweed, flat-stem pondweed
Distribution: British Columbia south on both sides of the Cascades to California, east to Idaho and Montana, and much of north central and northeast United States and adjacent Canada.
Habitat: Lakes, ponds and streams.
Origin: Native
Flowers: July - August
Potentilla anglicaEnglish cinquefoil, wood cinquefoil
Origin: Introduced
Potentilla anserina
Distribution: Widely distributed across Washington; distributed across much of North America except south-central and southeastern U.S.
Habitat: Wet, alkaline areas from coast to arid inlands.
Origin: Native
Flowers: April-August
ssp. anserina – silvery cinquefoil, common silverweed
ssp. pacifica – Pacific silverweed
Potentilla argenteahoary cinquefoil, silver cinquefoil
Distribution: Introduced and established in eastern United states and southern Canada; northeast Washington and a few places in Idaho.
Habitat: Sandy or gravely soil.
Origin: Introduced
Flowers: June - July
Potentilla biennisbiennial cinquefoil
Distribution: Occurring chiefly east of the Cascades crest in Washington; Yukon Territories south to California, east to the Rocky Mountains; also in South Dakota.
Habitat: Disturbed areas, typically where moist to wet.
Origin: Native
Flowers: May-August
Potentilla breweriBrewer's cinquefoil
Distribution: Mountains of central and southeast Oregon and northern California; occasional in the Wenatchee Mountains of Washington.
Habitat: Moist meadows and stream banks to open slopes, mid- to high elevations.
Origin: Native
Flowers: June - August
Potentilla drummondiiDrummond's cinquefoil
Distribution: Alaska to California, east to Alberta, Montana and Utah; in the Olympic and Cascade Mountains of Washington
Habitat: Forest openings, meadows and high ridges, mid- to high elevations in the mountains
Origin: Native
Flowers: July - August
Potentilla flabellifoliafan-leaf cinquefoil, fringe-leaf cinquefoil, fan-foil
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California and Nevada, east to Alberta, Montana and Wyoming.
Habitat: Common in moist meadows, mid- to high elevations in the mountains.
Origin: Native
Flowers: June-August
Potentilla glaucophyllablueleaf cinquefoil, different-leaved cinquefoil, diverse-leaved cinquefoil, vari-leaved cinquefoil
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska south to California, east to the Rocky Mountains.
Habitat: Moist alpine and subalpine meadows, and along stream banks in high mountain forests.
Origin: Native
Flowers: June-August
Potentilla gracilis
Distribution: Widely distributed throughout Washington; Alaska south to California, east to Saskatchewan and the Dakotas.
Habitat: Varied habitats; moderately saline soil, grasslands, moist areas in shrub-steppe, forested mountains and subalpine meadows.
Origin: Native
Flowers: July-August
var. brunnescens – glandular cinquefoil
var. flabelliformis – comb-leaf cinquefoil, Elmer's cinquefoil, Idaho cinquefoil
var. gracilis – Hall's cinquefoil, slender cinquefoil, wooly cinquefoil
var. pulcherrima – beautiful cinquefoil
Potentilla hyparcticasubarctic cinquefoil
Origin: Native
Potentilla inclinatagrey cinquefoil
Origin: Introduced from central and southern Europe
– Jepson's cinquefoil
Potentilla newberryiNewberry's cinquefoil
Origin: Native
Flowers: April - July
Potentilla niveasnow cinquefoil
Distribution: Alaska to British Columbia, east to Quebec, south in the Rocky Mountains to Colorado.
Habitat: Arctic tundra and gravel bars to alpine slopes and meadows.
Origin: Native
Flowers: June - August
Potentilla norvegicaNorwegian cinquefoil, rough cinquefoil
Distribution: Occurring on both sides of the Cascades crest in Washington; widely distributed throughout much of North America.
Habitat: Usually in moist soil, often along irrigation ditches or in waste places.
Origin: Native
Flowers: May-August
Potentilla ovinasheep cinquefoil
Origin: Native
var. ovina – sheep cinquefoil
Potentilla pensylvanica
Origin: Native
Potentilla rectasulphur cinquefoil
Distribution: Widely distributed throughout Washington; widely distributed throughout most of North America.
Habitat: Roadsides, trails, disturbed ground.
Origin: Introduced
Flowers: June-July
Potentilla rivalisbrook cinquefoil
Distribution: British Columbia south, east of the Cascades in Washington, down the Columbia River Gorge and the Willamette Valley to southwest Oregon and coastal California, east to Minnesota and New Mexico.
Habitat: Damp soil, especially along rivers and around lakes, ponds, and swamps.
Origin: Native
Flowers: May - September
Potentilla supinabushy cinquefoil
Distribution: In scattered locations in Washington, mostly east of the Cascades; British Columbia south to Texas, east to northeastern U.S.
Habitat: Sandy stream banks, lake shores, and moist flats.
Origin: Native
Flowers: June-July
ssp. paradoxa – bushy cinquefoil
Potentilla villosanorthern cinquefoil, villous cinquefoil
Distribution: Occurring in the North Cascades, Olympic Mountains, and at Mt. Rainier in Washington; Alaska to Oregon.
Habitat: Arctic tundra to alpine ridges, talus slopes and rock crevices.
Origin: Native
Flowers: July-September
Poteridium annuumannual burnet, prairie burnet
Origin: Introduced
Poterium sanguisorba
Distribution: Chiefly west of the Cascades in Washington; occurring in many areas of North America.
Habitat: Waste places.
Origin: Introduced
Flowers: June-August
var. polygamum – burnet bloodwort, fodder burnet, salad burnet
Prosartes hookeriHooker's fairy bells, fairy-bells
Distribution: Both sides of the Cascades in Washington; British Columbia south to Oregon, east to Montana.
Habitat: Moist, shady, wooded areas, sea level to mid-elevations in the mountains.
Origin: Native
Flowers: April-July
Prosartes smithiiSmith's fairy bells
Distribution: Occurring west of the Cascades crest in Washington; British Columbia to California.
Habitat: Open to dense moist woods at lower elevations.
Origin: Native
Flowers: April-June
Prosartes trachycarpawartberryfairy bells
Distribution: Occurring east of the Cascades crest in Washington; British Columbia south to Oregon, east to the Rocky Mountains and Great Plains of the U.S. and Canada, reaching Ontario and Michigan.
Habitat: Wooded slopes, often near streams, and in aspen groves.
Origin: Native
Flowers: May-July
Prunella vulgaris
Distribution: Throughout Washington; occurring throughout all of North America.
Habitat: Moist areas, sea level to moderate elevations in the mountains.
Origin: Both native and introduced
Flowers: May-September
var. lanceolata – heal-all, self-heal
var. vulgaris – heal-all, self-heal
Prunus americanaAmerican plum, wild plum
Distribution: Northeast Canada and United States, occasionally west to Montana and Utah; rare in Washington.
Habitat: Along watercourses, and on open or wooded, moist or dry areas from the plains into the lower mountains.
Origin: Introduced
Flowers: April - May
Prunus armeniacaapricot
Origin: Introduced
Prunus aviumsweet cherry
Distribution: Distributed widely throughout Washington; widely distributed throughout much of North America.
Habitat: Forest edges, fields, wastelots, and other disturbed areas.
Origin: Introduced
Flowers: April-May
Prunus cerasiferacherry plum
Distribution: Introduced and escaped, mostly in Western Washington, but also in southeast Washington.
Habitat: Open, disturbed areas.
Origin: Introduced
Flowers: March-April
Prunus cerasussour cherry
Origin: Introduced
Prunus domesticacultivated plum
Distribution: Occurring on both sides of the Cascades in Washington; Washington south to California, east to Idaho and Utah; in scattered locations of central and northeastern U.S.
Habitat: Fields, roadsides, forest openings, abandoned homesteads, and other disturbed areas.
Origin: Introduced
Flowers: March-May
Prunus dulcisalmond
Distribution: Escaped from cultivation sporadically in western North America. Native to Asia.
Habitat: Disturbed areas, riparian zones.
Origin: Introduced
Flowers: March-May
Prunus emarginatabitter cherry
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia south to California, east to the Rocky Mountains.
Habitat: Moist woods or somewhat moist places in shrub-steppe, sea level to mid-elevations in the mountains.
Origin: Native
Flowers: April-June
Prunus laurocerasuslaurel cherry, cherry-laurel
Distribution: Introduced ornamental, occasionally escaping west of the Cascades in Washington.
Habitat: Waste areas.
Origin: Introduced
Prunus lusitanicaPortugal laurel
Origin: Introduced
Prunus mahalebmahaleb cherry, perfumed cherry
Distribution: Introduced species used as budding stock for cherries, sometimes escaping.
Habitat: Disturbed soil.
Origin: Introduced
Flowers: May - June
Prunus padusEuropean bird cherry
Distribution: Introduced in Alaska and in Pennsylvania and a few neighboring states in eastern United States
Habitat: Ornamental, occasionally escapes
Origin: Introduced
Flowers: May
Prunus persicapeach
Origin: Introduced
Prunus ×pugetensisPuget Sound cherry
Distribution: Southwestern B.C through Puget Trough of Washington.
Habitat: Low elevations in forests or forest edges, or disturbed areas, typically where both parent species are present.
Origin: Native
Flowers: April-May
Prunus serotinablack cherry, rum cherry
Origin: Introduced
Prunus spinosablackthorn
Distribution: Introduced and escaping in southeast Washington and adjacent Idaho, also in western Oregon.
Habitat: Moist draws and hillsides.
Origin: Introduced
Flowers: April
Prunus tomentosaNanking cherry
Origin: Introduced
Prunus virginianacommon chokecherry, western chokecherry, white chokecherry
Distribution: Alaska, Canada and much of the United States
Habitat: Foothills and lowlands, more common in drier areas
Origin: Native
Flowers: May - Early July
Prunus yedoensisYoshino cherry
Origin: Introduced
Psathyrostachys junceaRussian-wild rye
Origin: Introduced
×Pseudelymus saxicola
Origin: Native
Pseudognaphalium californicumCalifornia cudweed, California everlasting, ladies tobacco, ladies' tobacco
Origin: Native
Flowers: June - July
Pseudognaphalium luteoalbumweedy cudweed, red-tip rabbit-tobacco, jersey rabbit tobacco
Distribution: Locally introduced, chiefly west of the Cascades.
Habitat: Disturbed waste ground.
Origin: Introduced
Flowers: June - October
Pseudognaphalium macouniisticky cudweed, winded cudweed, Macoun's rabbit-tobacco, Macoun's rabbit tobacco
Origin: Native
Pseudognaphalium stramineumcotton batting cudweed, cotton batting plant
Distribution: Widely distributed throughout much of Washington; British Columbia south to California, east to the Great Plains of the U.S.; New York south to South Carolina.
Habitat: Open, usually moist places, often on disturbed soil.
Origin: Native
Flowers: June-October
Pseudognaphalium thermaleslender cudweed, northwestern rabbit-tobacco
Distribution: Occurring on both sides of the Cascades crest in Washingotn; British Columbia south to California, east to Montana and Utah.
Habitat: Dry, sandy banks and ditches, open woods of ponderosa pine and Douglas fir, and mixed deciduous forests.
Origin: Native
Flowers: June-September
Pseudoroegneria spicata?bluebunch wheatgrass
Distribution: British Columbia south, chiefly east of the Cascade crests, but also in the coastal mountains, to California, east to the Dakotas and New Mexico.
Habitat: From the plains to mid-elevations in the mountains.
Origin: Native
Flowers: June - August
Pseudostellaria jamesianasticky-starwort
Distribution: East of the Cascades crest in Washington; Washington south to California, east to Idaho, Wyoming and New Mexico.
Habitat: Moist or dry open woods, rocky slopes and meadows, from moderate to high elevations.
Origin: Native
Flowers: May-July
Pseudotsuga menziesii
Distribution: British Columbia to California, east to Alberta and Colorado
Habitat: Moist to dry areas from sea level to mid-elevations in the mountains, occasionally to timberline
Origin: Native
Cones: April - May
var. glauca – pino real Colorado, Rocky Mountain Douglas-fir
var. menziesii – Douglas-fir
Psilocarphus brevissimusdwarf woolly-marbles
Distribution: Occurring east of the Cascades crest in Washington; British Columbia south to California, east to the Rocky Mountains.
Habitat: Dried beds of vernal pools.
Origin: Native
Flowers: May-July
var. brevissimus – dwarf woollyheads
Psilocarphus elatiortall woollyheads
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia south to California, east to Idaho and Montana.
Habitat: Dried beds of vernal pools and other open, moist places.
Origin: Native
Flowers: May-August
Psilocarphus oregonusOregon woollyheads
Distribution: Occurring east of the Cascades in Washington; Washington south to California, east to Idaho and Nevada.
Habitat: Dried beds of vernal pools.
Origin: Native
Flowers: May-July
Psilocarphus tenellusslender woollyheads
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia south 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
Pteridium aquilinum
Distribution: Widely distributed throughout Washington; widely distributed throughout North America; circumboreal.
Habitat: Common in moist to dry woods, open slopes and disturbed sites
Origin: Native
Spores: Spores April-October
ssp. pubescens – bracken, northern bracken
Pterospora andromedeawoodland pinedrops
Distribution: Widely distributed throughout Washington; British Columbia south to California, east to South Dakota and Texas.
Habitat: Common in humas in coniferous forests, especially ponderosa pine forests.
Origin: Native
Flowers: June-August
Puccinellia distansweeping alkaligrass, European alkali grass
Distribution: Occurring east of the Cascades in Washington; North-central British Columbia south, chiefly east of the Cascades, to California, east through most of Canada and to the east base of the Rockies.
Habitat: Moist soil, especially where alkaline.
Origin: Introduced
Flowers: June-August
Puccinellia lemmoniiLemmon's alkali grass
Origin: Native
Flowers: June - July
Puccinellia maritimacoast alkaligrass
Origin: Introduced
Puccinellia nutkaensisNootka alkali grass, shining alkali grass
Origin: Native
Puccinellia nuttallianaNuttall's alkali grass
Origin: Native
Flowers: June - August
Puccinellia pumiladwarf alkali grass
Origin: Native
Flowers: June - August
Pueraria montanakudzu
Origin: Introduced
Pulmonaria ovalisoval lungwort
Origin: Introduced
Purshia tridentataantelope-brush, bitterbrush
Distribution: Widely distributed east of the Cascades crest in Washington; British Columbia south to California, east to Montana, Colorado and New Mexico.
Habitat: Sagebrush desert and shrub-steppe to ponderosa pine forests.
Origin: Native
Flowers: April-June
Pyracantha coccineafirethorn, scarlet firethorn
Distribution: Occurring in scattered locations across Washington; British Columbia south to California, east to the Atlantic Coast along the southern half of the U.S.
Habitat: Disturbed areas, wastelots, and forest margins often near towns and cities where escaped from cultivation.
Origin: Introduced from southern Europe
Flowers: May-June
Pyracantha fortuneanaChinese firethorn
Origin: Introduced
Pyrola aphyllaleafless wintergreen
Origin: Native
Pyrola asarifoliacommon pink wintergreen, liver-leaf wintergreen
Distribution: Widely distributed throughout much of forested Washington except for the southeast corner; Alaska south to California, east to Colorado in the west, and across the northern half of the United States to the Atlantic.
Habitat: Moist ground in woodlands and forests, lowlands to mid-elevations.
Origin: Native
Flowers: June-September
ssp. asarifolia – pink pyrola
ssp. bracteata – pink pyrola
Pyrola chloranthagreen-flower wintergreen
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
Pyrola dentatatoothleaf pyrola
Origin: Native
Pyrola ellipticawhite wintergreen
Origin: Native
Pyrola minorlesser wintergreen, snowline wintergreen
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
Pyrola pictawhite-vein wintergreen
Distribution: Both sides of the Cascades, British Columbia to California, east to South Dakota and New Mexico
Habitat: Coniferous woods, especially ponderosa pine, moderate to mid-elevations in the mountains
Origin: Native
Flowers: June - August
Pyrrocoma carthamoideslarge-flowered goldenweed
Distribution: Occurring east of the Cascades crest in Washington; British Columbia south to California, east to Idaho, Montana, Wyoming, and Nevada.
Habitat: Open hillsides and meadows, from the valleys and plains to moderate elevations in the mountains.
Origin: Native
Flowers: July-August
var. carthamoides – Columbia goldenweed, rayless goldenweed
var. cusickii – narrowhead goldenweed
Pyrrocoma hirtahairy goldenweed, sticky goldenweed
Distribution: Mountains of central Washington, and the mountains of northeast Oregon and adjacent Washington and Idaho, south to northeast California.
Habitat: Meadows and open or sparsely wooded slopes in the foothills to moderate elevations in the mountains.
Origin: Native
Flowers: July - August
var. sonchifolia – large sticky goldenweed
Pyrrocoma liatriformisPalouse goldenweed
Distribution: Occurring in the Palouse region of southeastern Washington.
Habitat: Grassy hillsides and prairies.
Origin: Native
Flowers: July-August
Pyrrocoma scaberulapalouse goldenweed
Distribution: Occurring in the southeastern corner of Washington, northeast Oregon and into Idaho.
Habitat: Grasslands and open hillsides at low to mid elevations.
Origin: Native
Flowers: July-August
Pyrus calleryanaCallery pear
Distribution: Occurring in scattered locations in lowland western Washington; occurring in eastern and southeastern U.S.
Habitat: Forest edges where previously disturbed.
Origin: Introduced
Flowers: April-May
Pyrus communiscommon pear
Origin: Introduced
Pyrus nivalissnow pear
Origin: Introduced