Cronquist's wild buckwheat

Eriogonum corymbosum Bentham var. cronquistii (Reveal) S. L. Welsh

Herbs, spreading, not scapose, (0.7-)1-1.5(-4) × 3-8 dm, glabrous, grayish. Stems spread-ing, usually with persistent leaf bases, up to 1/ 4 height of plant; caudex stems spreading; aerial flowering stems spreading to erect, slender, solid, not fistulose, 0.5-1 dm, glabrous, tomentose among leaves. Leaves sheathing up stems 1-4 cm, 1 per node; petiole 0.3-0.8 cm, tomentose; blade elliptic, 0.5-2 × 0.4-1 cm, densely white-tomentose abaxially, sparsely so and greenish adaxially, margins crenulate. Inflorescences subcapitate to cymose, 1-7 × 1-5 cm; branches dichotomous, glabrous; bracts 3, scalelike, triangular, 1 mm. Peduncles absent. Involucres 1 per node or 2-4 per cluster, turbinate, (2.5-)3-3.5 × 2-2.5 mm, glabrous; teeth 5, erect, 0.6-1 mm. Flowers (1.5-)2-3 mm; perianth white, glabrous; tepals connate proximal 3, monomorphic, oblanceolate; stamens exserted, 2.5-4 mm; filaments pilose proximally. Achenes light brown, 2-2.5 mm, glabrous. 2n = 40.

Flowering Jul-Sep. Granitic talus slopes and outcrops, sagebrush communities, pinyon-juniper woodlands; of conservation concern; 2500-2800 m; Utah.

Eriogonum cronquistii is known only from the western slope and summit of Bull Mountain, Henry Mountains, Garfield County. The Bureau of Land Management considers it a “sensitive” species.