Polygonaceae
Buckwheat Family
12 genera
72 species
47 subspecies and varieties
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Aconogonon davisiaeNewberry's fleeceflower, Davis' knotweed, Davis's knotweed
Distribution: Cascades and Olympic mountains of Wahington, south to California, east to Idaho and western Montana.
Habitat: Slopes and ridges in the subalpine and alpine.
Origin: Native
Flowers: June-September
Aconogonon phytolaccifoliumalpine fleeceflower
Distribution: East of the Cascades in Washington; Alaska south to the Sierra Nevada of California, east to Idaho and western Montana.
Habitat: Subalpine to alpine ridges, meadows and talus slopes.
Origin: Native
Flowers: June-August
var. phytolaccifolium – poke knotweed
Bistorta bistortoidesAmerican bistort, western bistort
Distribution: Occurring on both sides of the Cascades in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Streambanks and moist or swampy meadows, middle elevations in the mountains to alpine slopes.
Origin: Native
Flowers: May-August
Bistorta viviparaalpine bistort, serpent-grass
Distribution: Occurring on both sides of the Cascades in northern Washington; Alaska south to Oregon, east to Montana, and south in the Rockies to New Mexico; across Canada to Newfoundland, south to Minnesota and Maine.
Habitat: Damp areas, shady woods, meadows and streambanks at mid- to high elevations in the mountains.
Origin: Native
Flowers: June-September
Chorizanthe watsoniifive-tooth spineflower, Watson's spineflower
Distribution: Occurring east of the Cascades crest in central Washington; Washington to California, east to Montana, Utah, or Arizona.
Habitat: Sandy to gravelly flats and slopes, mixed grassland, saltbush and sagebrush communities, often where disturbed.
Origin: Native
Flowers: May-July
Eriogonum baileyiBailey's buckwheat
Distribution: Occurring east of the Cascades crest in the central region of Washington; northern Washington to California, east to Idaho and Utah.
Habitat: Sand or gravel flats and slopes, grassland and shrub-steppe, open forest, and washes.
Origin: Native
Flowers: April-June
var. baileyi – Bailey's buckwheat
Eriogonum cernuumnodding buckwheat
Distribution: Occurring only in Franklin County, where disjunct from primary range of species; southeastern Oregon and adjacent Idaho to eastern California, also in Rocky Mountains and Great Plains.
Habitat: Sand, gravel or clay slopes and flats, shrub-steppe, and grasslands.
Origin: Native
Flowers: May-June
Eriogonum codiumbasalt desert buckwheat, Umptanum buckwheat
Distribution: Occurring east of the Cascades crest in Washington, where endemic to Benton County.
Habitat: Volcanic soils in sagebrush along the Columbia River.
Origin: Native
Flowers: May-August
Eriogonum compositumarrow-leaf buckwheat, northern buckwheat
Distribution: Occurring chiefly east of the Cascades crest in Washington; Washington to California, east to Idaho.
Habitat: Dry, open areas, rocky slopes and cliffs from low elevations nearly to the subalpine.
Origin: Native
Flowers: May-July
var. compositum – northern buckwheat
var. lancifolium – wild buckwheat
var. leianthum – smooth arrow-leaf wild buckwheat
Eriogonum douglasiiDouglas's buckwheat
Distribution: Occurring east of the Cascades crest in Washington, chiefly in the central region; Washington to California, east to Idaho and Nevada.
Habitat: Sagebrush or juniper flats to ponderosa pine forests, often on lithosol.
Origin: Native
Flowers: May-July
var. douglasii – Douglas' buckwheat
Eriogonum elatumrush buckwheat, tall buckwheat
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to southern Idaho and Nevada.
Habitat: Sand and gravel slopes and flats, grasslands, sagebrush desert, ponderosa pine forest openings, and montane ridges.
Origin: Native
Flowers: June-August
var. elatum – tall buckwheat
Eriogonum flavumyellow buckwheat
Distribution: Occurring east of the Cascades crest in southeastern Washington; Alaska to northeastern Oregon, east to the northern Great Plains.
Habitat: Open knolls in grasslands to alpine ridges and scree.
Origin: Native
Flowers: June-August
var. piperi – Piper's buckwheat, yellow buckwheat
Eriogonum heracleoidesbractless parsnip-flowered wild buckwheat, parsnip-flowered buckwheat, parsnip-flowered eriogonum
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to Montana, Wyoming and Colorado.
Habitat: Deeper soil of shrub-steppe to ponderosa pine forests and rocky ridges at middle elevation in the mountains.
Origin: Native
Flowers: May-July
Eriogonum maculatumspotted buckwheat
Distribution: Collected once (1884) in Yakima County in Washington and now considered extirpated; southeastern Oregon to southwestern Idaho, south to Baja California, Mexioca and east to New Mexico.
Habitat: Sand, gravel or clay slopes and flats, grassland, and shrub-steppe.
Origin: Native
Flowers: May-June
Eriogonum marifoliummarum-leaf wild buckwheat, mountain buckwheat
Distribution: Reported from east of the Cascades crest in Washington, but no specimens seen; central Washington to California, east to northwestern Nevada.
Habitat: Gravelly flats in lodgepole and ponderosa pine forests to alpine ridges and talus slopes.
Origin: Native
Flowers: June-August
var. marifolium – marum-leaf wild buckwheat, mountain buckwheat
Eriogonum microthecumslenderbush buckwheat
Distribution: Occurring east of the Cascades crest in central Washington; central Washington to California, east to the Rocky Mountains.
Habitat: Sandy deserts to lower mountain slopes, chiefly with sagebrush.
Origin: Native
Flowers: June-August
var. laxiflorum – slenderbush buckwheat
Eriogonum niveumsnow buckwheat
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to Oregon, east to Idaho.
Habitat: Sagebrush desert, dry ponderosa pine forest openings, in deep or sandy soil.
Origin: Native
Flowers: June-September
Eriogonum nudumbare-stem buckwheat, naked buckwheat
Distribution: Occurring on both sides of the Cascades crest in southern Washington; southern Washington to California and Nevada.
Habitat: Sandy or rocky places from the lowlands to subalpine.
Origin: Native
Flowers: June-August
var. nudum – barestem buckwheat, naked buckwheat
Eriogonum ovalifoliumcushion buckwheat, oval-leaved eriogonum
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Sagebrush deserts, juniper and ponderosa pine forests, to alpine ridges.
Origin: Native
Flowers: May-August
var. nivale – Sierra cushion buckwheat
var. ovalifolium – cushion wild buckwheat
var. purpureum – purple cushion wild buckwheat
Eriogonum pyrolifoliumalpine buckwheat, oarleaf buckwheat, Shasta wild buckwheat
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east to Idaho and Montana.
Habitat: Open, often rocky areas, from middle elevations to the alpine in the mountains.
Origin: Native
Flowers: July-September
Eriogonum sphaerocephalumrock buckwheat, round-headed eriogonum
Distribution: East of the Cascades in Washington; Chelan County, Washington south to California and east to Idaho and Nevada.
Habitat: Sagebrush or juniper flats to ponderosa pine forests at low elevations.
Origin: Native
Flowers: May-July
var. halimioides – rock buckwheat
var. sphaerocephalum – rock buckwheat
var. sublineare – scabland wild buckwheat
Eriogonum strictumstrict buckwheat
Distribution: Occurring east of the Cascades crest in Washington; Washington south to California, east to Montana, Idaho, and Nevada.
Habitat: Sandy or rocky soils, sagebrush desert to ponderosa pine forests.
Origin: Native
Flowers: May-July
var. anserinum – Goose Lake wild buckwheat
var. proliferum – strict buckwheat
var. strictum – strict buckwheat
Eriogonum thymoidesthyme buckwheat, thyme-leaf wild buckwheat
Distribution: Occurring east of the Cascades crest in central Washington; central Washington to Oregon, east to Idaho.
Habitat: Sagebrush deserts, dry ponderosa pine forest openings, and open ridges in lower mountains.
Origin: Native
Flowers: April-June
Eriogonum umbellatumsulfur buckwheat, sulfurflower
Distribution: On both sides of the Cascades in Washington; British Columbia south to California, east to Montana, Colorado and New Mexico.
Habitat: Sagebrush deserts to alpine rocky ridges.
Origin: Native
Flowers: June-September
var. devestivum – emperor's sulfur flower
var. ellipticum – sulfur flower
var. haussknechtii – sulfur flower
var. hypoleium – sulfur flower
var. majus – subalpine sulfur flower
var. sandbergii – Sandberg's sulfur flower
Eriogonum vimineumbroom buckwheat
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to Idaho and Nevada.
Habitat: Sagebrush deserts and dry ponderosa pine forest openings; tolerant of dry, disturbed conditions.
Origin: Native
Flowers: June-September
Fagopyrum esculentumgarden buckwheat
Distribution: Introduced in much of the United States.
Habitat: Roadsides, fields, waste areas; frequently escapes cultivation.
Origin: Introduced
Flowers: June - September
Fallopia baldschuanicaBukhara fleeceflower, Chinese fleecevine, mile-a-minute vine
Distribution: Occurring chiefly west of the Cascades crest in Washington; southern British Columbia to Oregon, east to Idaho, also in scattered locations across North America.
Habitat: Roadsides, ditches, embankments, forest edge, and other disturbed open areas.
Origin: Introduced from central Asia
Flowers: Aug.-Sept.
Fallopia ×bohemicaBohemian knotweed, hybrid knotweed
Distribution: Occurring chiefly west of the Cascades crest in Washington; Alaska to Oregon, east to Montana, and in scattered locations across North America.
Habitat: Riparian zones, roadsides, ditches, wastelots, and other disturbed open areas generally at low elevations.
Origin: Introduced from eastern Asia
Flowers: July-October
Fallopia convolvulusblack bindweed, climbing bindweed, ivy bindweed
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Roadsides, ditches, wastelots, cultivated fields, and other disturbed open areas.
Origin: Introduced from Europe
Flowers: May-October
Fallopia japonicaJapanese knotweed
Distribution: Occurring chiefly west of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Riparian zones, roadsides, ditches, wastelots, and other disturbed open areas.
Origin: Introduced from eastern Asia
Flowers: June-September
var. japonica – Japanese knotweed
Fallopia sachalinensisgiant knotweed
Distribution: Occurring chiefly west of the Cascades crest and east in the Columbia River Gorge in Washington; Alaska to California, east to Idaho and Montana, also in eastern North America.
Habitat: Riparian zones, roadsides, meadows, ditches, and other disturbed areas generally at low elevations.
Origin: Introduced from eastern Asia
Flowers: July-September
Oxyria digynamountain-sorrel
Distribution: Alaska to California, east to Montana, Colorado and New Mexico; also across Canada to Labrador, and the Olympics in Washington
Habitat: Moist, usually rocky ground, alpine to subalpine
Origin: Native
Flowers: Late June - August
Oxytheca dendroideatreelike puncturebract
Origin: Native
Flowers: June - August
ssp. dendroidea – treeline puncturebract
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 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
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
Distribution: Occurring in the east end of the Columbia River Gorge in Washington; south-central Washington to California.
Habitat: Dry rocky slopes, gravelly ground at low elevations.
Origin: Native
Flowers: May-July
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, prickly knotweed
Distribution: Occurring in the east end of the Columbia River Gorge in Washington; south-central Washington to California.
Habitat: Vernal pools, seasonally damp ground at low elevations.
Origin: Native
Flowers: June-July
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: Occurring west of the Cascades crest and east in the Columbia River Gorge in Washington; British Columbia to California, east to Idaho, Montana, and Wyoming.
Habitat: Balds, prairies, and headlands in gravelly, sandy or heavy, dry or moist soil at low elevations.
Origin: Native
Flowers: June-September
Rheum rhabarbarumrhubarb
Distribution: Occurring in scattered locations on both sides of the Cascades crest; Alaska an Yukon Territory, Rocky Mountain states, and eastern North America.
Habitat: Open, disturbed areas, often associated with former homesteads.
Origin: Introduced
Flowers: May-June
Rumex acetosa
Distribution: Introduced in scattered locations in North America; occasional in British Columbia, western Washington and Oregon, and northcentral Montana.
Habitat: Disturbed soil and wasteland.
Origin: Introduced
Flowers: April - July
Rumex acetosellacommon sheep sorrel
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Balds, prairies, meadows, pastures, fields, roadsides, wastelots, lawns and other disturbed open areas from the lowlands to middle elevations in the mountains.
Origin: Introduced from Eurasia
Flowers: May-August
Rumex conglomeratusclustered dock, sharp dock
Distribution: Occurring west of the Cascades crest in Washington; British Columbia to California, also along southern U.S. border to central and eastern U.S.
Habitat: A weed of waste ground.
Origin: Introduced
Flowers: June-September
Rumex crispuscurly dock, sour dock
Distribution: Introduced and common in most of North America from the coast to inland mountains.
Habitat: Moist meadows.
Origin: Introduced
Flowers: June - September
Rumex dentatustoothed dock
Origin: Introduced
Rumex maritimusgolden dock
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to eastern North America except for southeastern U.S.
Habitat: Mostly in wet places.
Origin: Native
Flowers: June-September
ssp. fueginus – American golden dock, Tierra del Fuego dock
Rumex obtusifoliusbitter dock
Distribution: Occurring on both sides of the Cascades in Washington; widely distributed throughout much of North America.
Habitat: Moist roadsides and wasteland.
Origin: Introduced
Flowers: March-September
Rumex occidentaliswestern dock, western dock o n
Distribution: Distributed on both sides of the Cascades in Washington; Alaska south to central California, east to North Dakota and New Mexico.
Habitat: Moist to swampy areas and wet meadows, from the sea coast to foothill valleys.
Origin: Native
Flowers: June-August
Rumex patientiapatience dock
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to Oregon, east to the Atlantic Coast.
Habitat: Roadsides and other disturbed, open ground
Origin: Introduced from Eurasia
Flowers: May-August
Rumex paucifoliusalpine sheep sorrel, alpine sorrel, mountain sorrel
Distribution: Occurring east of the Cascades crest in Washington; southern British Columbia to California, east to the Rocky Mountains.
Habitat: moist grasslands, stream banks, and montane to alpine meadows.
Origin: Native
Flowers: June -August
Rumex persicarioidesseashore dock, yellow dock
Distribution: Occurring along the coast in Washington; British Columbia to California, also in eastern North America.
Habitat: Beaches, shores, and slightly saline marshes.
Origin: Native
Flowers: June-August
Rumex salicifoliuswillow dock
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Atlantic Coast
Habitat: Streambanks, moist meadows, beaches, alkaline shores, roadsides, and other open places from low to moderate elevations.
Origin: Native
Flowers: May-July
var. angustivalvis – western willow dock
var. transitorius – narrow-leaved dock, Pacific willow dock
var. triangulivalvis – or triangular-valved dock, white, white willow
var. utahensis – Utah willow dock
Rumex sanguineusred-vein dock
Distribution: Occurring chiefly west of the Cascades crest in Washington; southwestern British Columbia to Oregon, also in eastern North America.
Origin: Introduced from Eurasia
Flowers: June-September
Rumex stenophyllusnarrow-leaved dock, narrowleaf dock
Origin: Introduced from Europe
Rumex venosusveiny dock, winged dock
Distribution: Occurring east of the Cascades crest in Washington; Alberta to California, east to the Rocky Mountains and Great Plains.
Habitat: Sand dunes and sandy river banks to dry, gravelly soil, sagebrush deserts and grasslands at low elevations.
Origin: Native
Flowers: April-June