Flora of Washington

Petrophytum cinerascens (orth. var. Petrophyton cinerascens) is a rare species of flowering plant in the rose family known by the common names halfshrub rockmat and Chelan rockmat. It is endemic to the state of Washington in the United States, where it occurs in just a few locations along the Columbia River in Chelan and Douglas Counties.

Allium scilloides, called the fragile onion, is a plant species endemic to the US State of Washington. It has been reported from only 4 counties, all on the eastern side of the Cascade Range: Klickitat, Kittitas, Yakima and Grant. It grows on barren, gravelly or rocky slopes at elevations of 300–1300 m. The species is sometimes cultivated in other regions as an ornamental.

Viola flettii is a species of violet known by the common name Olympic violet. Native to the northeastern and eastern Olympic Mountains of Washington in northwestern United States, it occurs on rocky outcrops and talus at subalpine and alpine elevations, i.e., from 1,340–2,000 metres (4,400–6,560 ft), and blooms from June through August.

Campanula piperi (Olympic bellflower, Olympic harebell, Piper's bellflower) is a species of flowering plant in the bellflower family, Campanulaceae. It is native to the Olympic Mountains on the Olympic Peninsula in the U.S. state of Washington. It has also been noted on Vancouver Island, British Columbia.

Astragalus sinuatus is a species of flowering plant in the legume family known by the common name Whited's milkvetch. It is endemic to Washington in the United States, where it is limited to one creek drainage on the western edge of the Columbia Basin. Its range measures about ten square miles in Chelan and Kittitas Counties in the central part of the state. This perennial herb has stems up to about 45 centimeters long. In April and May it produces yellowish or cream-colored flowers with purple-tinged keels. The fruit is a legume pod which is so tough it sometimes requires pliers to crack it

Allium dictuon is a species of wild onion known by the common name Blue Mountain onion. It is native to a small section of the Blue Mountains straddling the border between southeastern Washington and northeastern Oregon in the United States. It grows in Columbia, Garfield and Walla Walla Counties in Washington, plus Umatilla and Wallowa Counties in Oregon.

Trifolium thompsonii is a species of flowering plant in the legume family known by the common name Thompson's clover.

Erythronium quinaultense, the Quinault fawn-lily, is a rare plant species endemic to a small region around Lake Quinault in Olympic National Park, Washington state, United States. Erythronium quinaultense produces egg-shaped bulbs up to 75 millimetres (3.0 in) long. Leaves are up to 20 centimetres (7.9 in) long. Scape is up to 25 centimetres (9.8 in) long, bearing one to three flowers. Tepals have yellow, white and pink bands perpendicular to the veins.

Allium constrictum, the Grand Coulee onion, is a plant species endemic to the US state of Washington. It is known from only three counties in the east-central part of the state: Douglas, Grant, and Lincoln. It grows on dry, sandy soils at elevations of 300–500 m.

Agastache occidentalis is a species of Agastache first described by Charles Vancouver Piper, and given its current name by Amos Arthur Heller. It is commonly known as western giant hyssop and giant horsemint.

Poa curtifolia is a species of grass found on serpentine soils in the Wenatchee Mountains of Washington State.

Pedicularis rainierensis is a species of flowering plant in the family Orobanchaceae commonly known as Mount Rainier lousewort. It is endemic to the vicinity of Mount Rainier in Washington state. The Mount Rainier lousewort has a imperiled status.

Lomatium thompsonii, commonly known as Thompson's desertparsley, is a perennial herb of the family Apiaceae endemic to Chelan and Kittitas County in Washington, United States. It grows in open, rocky slopes and pine forests. Flowers bloom May to June.

Iliamna longisepala, known by the common name long sepal globemallow, is a perennial plant species in the Malvaceae family.

Delphinium viridescens is a species of flowering plant in the buttercup family known by the common name Wenatchee larkspur. It is endemic to central Washington state in the United States, where it occurs in the Wenatchee Mountains in Chelan and Kittitas Counties.

Androsace nivalis is a species of flowering plant in the primrose family Primulaceae with the common name snow dwarf-primrose. It was previously placed in the genus Douglasia, which is now known to be nested within Androsace.

Silene seelyi is a species of flowering plant in the family Caryophyllaceae known by the common names Seely's catchfly and Seely's silene. It is endemic to Washington state in the United States, where it is limited to the Wenatchee Mountains of Chelan and Kittitas Counties. This perennial herb grows from a taproot and branching caudex. The branching stems are up to 30 centimeters long. The thin leaves are mainly lance-shaped and measure up to 2 centimeters long. They are oppositely arranged on the stem. The inflorescence contains many leaves and a few flowers. The flowers have bell-shaped

Lomatium cuspidatum (Wenatchee desertparsley) is a perennial herb of the family Apiaceae, native to the U.S. state of Washington. It is found primarily on open rocky slopes in the Wenatchee Mountains, strongly associated with serpentine scree and soils.

Hackelia venusta is a rare species of flowering plant in the borage family known by the common name showy stickseed, or lesser showy stickseed. It is endemic to Washington state in the United States, where it is known from only one canyon in Chelan County. There is only one small population with a global distribution of less than one hectare. The plant was federally listed as an endangered species of the United States in 2002. This is a perennial herb producing several leafy stems up to 20 to 40 centimeters (7.9 to 15.7 in) tall from a taproot. The plant blooms in April and May, bearing

Eriogonum codium is a species of wild buckwheat known by the common names basalt desert buckwheat and Umtanum Desert wild buckwheat. It is endemic to Washington in the United States, where it is known only from Hanford Reach National Monument in Benton County. It was discovered in 1995 during an inventory of the biodiversity of the monument and described to science in 1997.

Erigeron flettii is a rare North American species of flowering plants in the family Asteraceae known by the common names Flett's fleabane or Olympic Mountains fleabane . Erigeron flettii is endemic to the Olympic Peninsula in the State of Washington. Many of the populations lie inside Olympic National Park. Erigeron flettii is a small perennial herb up to 15 centimeters (8 inches) in height. Most of the leaves are clustered around the base of the stems. They are lance-shaped, dark green on most of the blade but with white along the edge. The plant generally produces only 1 flower head per

Erigeron basalticus is a species of flowering plant in the family Asteraceae known by the common names basalt fleabane and basalt daisy. It is endemic to Washington state in the United States, where it is known only from the banks of the Yakima River and its tributaries in Yakima and Kittitas Counties. This perennial herb grows from a taproot and branching caudex, producing spreading or hanging stems up to 25 centimeters long. They are leafy, hairy, and glandular. The leaves have wedge-shaped or oval blades with three lobes and are hairy in texture. The hairy flower head contains white ray

Polemonium pectinatum is a species of flowering plant in the phlox family known by the common names Washington Jacob's-ladder and Washington polemonium. It is endemic to the state of Washington in the United States, where it occurs in the Columbia Basin, including the Channeled Scablands and the Palouse.

Lupinus garfieldensis, commonly known as the Garfield lupine or the Asotin Silky lupine, is a species of lupine native to eastern Washington state.

Erigeron piperianus is a species of flowering plant in the family Asteraceae known by the common name Piper's fleabane. It has been found only in the state of Washington in the northwestern United States. Erigeron piperianus is a small perennial herb rarely more than 12 centimeters (4.8 inches) tall, producing a woody taproot. The leaves are linear to narrowly oblanceolate, are 2 to 4 cm long, and are sparsely covered in bristly appearing hairs (hispid). The plant produces many stems, but with only 1 flower head per stem. Each head has 25–40 yellow ray florets surrounding numerous yellow disc

Chaenactis thompsonii is a North American species of flowering plants in the aster family known by the common name Thompson's pincushion and native to Washington State.

Lomatium quintuplex is a perennial herb in the carrot family Apiaceae, native to the U.S. state of Washington, and known by the common name Umtanum desertparsley. It grows in thin rocky soil on open slopes and is known only from a small region in Kittitas and Yakima counties.

Eucephalus glaucescens is a North American species of flowering plant in the family Asteraceae known by the common name Klickitat aster. It grows on rocky slopes and in subalpine meadows at high elevations on and near Mount Adams in the south-central part of the US State of Washington. Eucephalus glaucescens is a perennial herb up to 160 cm (5+1⁄3 ft) tall, with a woody caudex. Stems are hairless. Leaves are whitish and waxy. One plant will usually produce 5-60 flower heads in a large array. Each head has 8-13 purple ray florets surrounding numerous yellow disc florets.

Lomatium roneorum, Rone's desert-parsley or Rone's biscuit-root, is a species of Lomatium native to chalky soils in the Chumstick formation in Washington State. The specific epithet commemorates the surname Rone, as determined by an auction for the naming rights.

Allium robinsonii, the Columbia River onion or Robinson's onion, is a rare plant species native to the US States of Washington and Oregon, although some studies suggest that the Oregon populations may now be extinct. The species has been reported from five counties in Washington (Ferry, Yakima, Grant, Franklin and Benton) and five in Oregon (Umatilla, Morrow, Gilliam, Sherman and Wasco). It is found in sand and gravel deposits along the lower Columbia River and some of its tributaries, usually at elevations less than 200 m. The species is also cultivated as an ornamental in other regions,