Distribution: Occurring west of the Cascades crest in southwestern Washington and in the Columbia River Gorge; southern Washington through the Willamette Valley to southwestern Oregon.

Habitat: Low ground, especially in places submerged in spring and drying out in summer.

Flowers: June-August

Origin: Native

Growth Duration: Perennial

Conservation Status: Threatened in Washington (WANHP)

Pollination: Bees, flies, butterflies, wasps

Herbaceous perennial from fibrous roots and a short, simple crown, the stems 1.5-5 dm. tall, divaricately branched, often from near the base.

Basal leaves without blades, the petioles elongate, hollow; cauline leaves with progressively shorter petioles, the blades narrowly elliptic, up to 1 cm. wide, sub-entire or with spiny teeth.

Flowers sessile in heads up to 1 cm. wide; involucral bracts narrow, spine-toothed, much surpassing the flowers; bracteoles subtending the flowers narrowly linear, also exceeding the flowers; calyx lobes 5, 3 mm. long, acuminate; corolla 5-lobed, white.

Fruit ovoid, 2 mm. long, covered with tapering scales 1-1.5 mm. long.