Comb Wash Buckwheat

Eriogonum clavellatum is relatively rare, known only from a few sites in the Four Corners area of San Juan County, Utah, Montezuma County, Colorado, and San Juan County, New Mexico. It has yet to be found in Arizona. The Comb Wash wild buckwheat is considered a “sensitive” species by the Bureau of Land Management throughout its range.

Subshrubs, spreading, not scapose, 1-2.5 × 3-8 dm, thinly floccose or glabrous, greenish to grayish. Stems spreading, with-out persistent leaf bases, up to 1/ 3 height of plant; caudex stems compact; aerial flowering stems spreading to erect, slender, solid, not fistulose, 0.06-0.2(-2.5) dm, thinly floccose or glabrous. Leaves cauline, 1 per node or fasciculate; petiole 0.05-0.1 cm, tomentose to floccose, rarely glabrous; blade oblanceolate, 1-1.5(-2) × 0.08-0.2 cm, densely white-tomentose abaxially, thinly tomentose and grayish or rarely glabrous and green adaxially, margins tightly revolute. Inflorescences umbellate to cymose, compact, 0.5-2 × 1-2 cm; branches dichotomous, thinly floccose or glabrous; bracts 3, scalelike, triangular, 1.5-2.5(-3) mm. Peduncles erect, 0.15-0.8 cm, glabrous. Involucres 1 per node, turbinate-campanulate, (3-)3.5-4.5(-5) × 2.5-4.5 mm, glabrous; teeth 5, erect, 0.6-0.9(-1.1) mm. Flowers (2.5-)3-3.5 mm; perianth white, glabrous; tepals connate proximal 4- 3, dimorphic, those of outer whorl broadly obovate to nearly fan-shaped, 2-2.5 mm wide, those of inner whorl slightly shorter and oblanceolate to spatulate, 0.9-1.5 mm wide; stamens long-exserted, 3-6 mm; filaments sparsely pilose proximally. Achenes light brown, 3-3.5 mm, glabrous.

Colo., N.Mex., Utah.

Flowering May-Jul.

Sandy to heavy clay washes and slopes, saltbush communities; of conservation concern; 1300-1800m.