Slender Woolly Buckwheat

Eriogonum gracile is a highly variable species. The low, spreading plants from the mountains of coastal central California with 2-3 mm involucres and (usually) yellowish flowers differ from the more erect plants represented by the type collection, which have 1.8-2 mm involucres and white flowers. Such plants are found mainly farther south, in the Mt. Diablo and Mt. Hamilton areas of Alameda, Contra Costa, and Stanislaus counties. Some populations of E. gracile from the Inner Coast Ranges of eastern San Luis Obispo County are slightly different from the norm and the epithet leucocladon has been adopted in some local floristic treatments to account for them. However, the type of E. leucocladon does not seem to be this phase.

Herbs, erect to spreading or somewhat decumbent, (0.7-)1.5-5(-7) dm, lanate to tomentose or floccose, rarely glabrous, greenish to whitish or grayish. Stems: aerial flowering stems erect, 0.5-2 dm, lanate to tomentose or floccose, rarely glabrous. Leaves basal and cauline; basal: petiole 1-4 cm, floccose, not winged, blade oblanceolate to oblong, (0.8-)1-4(-6) × 0.5-2 cm, tomentose abaxially, less so to floccose and greenish to grayish adaxially; cauline: petiole 0.3-2 cm, floccose, blade oblanceolate, 0.5-3 × 0.3-1.5 cm, similar to basal blade. Inflorescences cymose, occasionally distally uniparous due to suppression of secondary branches, open to somewhat diffuse, 0.5-4 × 0.5-3 cm; branches lanate to tomentose or floccose, rarely glabrous, straight or nearly so, not inwardly curved distally; bracts 0.5-3 × 1-3 mm. Peduncles absent. Involucres somewhat appressed to branches, turbinate, (1.8-)2-3 × 1.5-2 mm, floccose or glabrous; teeth 5, erect, 0.3-0.6 mm. Flowers 1.5-3 mm; perianth white to pink or yellow, glabrous; tepals monomorphic, lanceolate to oblong; stamens mostly included, 1-1.5 mm; filaments pilose proximally. Achenes brown, 3-gonous, 1-2 mm. 2n = 22.

Eriogonum vimineum Douglas ex Bentham subsp. gracile (Bentham) S. Stokes

Eriogonum gracile is a species of wild buckwheat known by the common name slender woolly buckwheat.