Crisp-leaf wild buckwheat

Eriogonum corymbosum var. divaricatum Torrey & A. Gray; E. corymbosum var. erectum Reveal & Brotherson; E. divergens Small; E. effusum Nuttall subsp. divaricatum (Torrey & A. Gray) S. Stokes; E. effusum subsp. durum S. Stokes; E. effusum subsp. salinum (A. Nelson) S. Stokes

Subshrubs or shrubs, 3-10 × 3-10 dm. Leaves cauline 1/ 2 or more length of flowering stem; petiole 0.2-0.6(-0.8) cm; blade lanceolate to oblanceolate or elliptic, 1-3(-4.5) × (0.3-)0.5-1.5 cm, usually densely tomentose on both surfaces, sometimes less so and greenish adaxially. Inflorescences 3-10 cm; branches tomentose to floccose. Involucres 1.5-3.5 × 1-2 mm. Flowers 2-3.5 mm; perianth white to cream, glabrous. 2n = 40.

Flowering Jul-Oct. Sandy to gravelly or clayey flats, washes, slopes, outcrops, and cliffs, saltbush, blackbrush, and sagebrush communities, pinyon-juniper and montane conifer woodlands; 1200-2700 m; Ariz., Colo., Utah, Wyo.

Variety corymbosum is the common white-flowered expression of the species. It occurs in northern Arizona, western Colorado, eastern and southern Utah, and southwestern Wyoming. Montane plants in the northern part of the range in Utah and Wyoming with long, narrow, erect leaves have been called var. erectum; desert plants in east-central Utah with small crenulate leaves have been called var. divaricatum. Hybrids between the shrubby var. corymbosum and the herbaceous E. brevicaule have been named E. ×duchesnense Reveal (as species, including E. corymbosum Bentham var. albogilvum Reveal). The hybrid is known from Rio Blanco County, Colorado (Goodrich 21999, BRY), Uintah County (Neese & Sinclair 15056, BRY), Utah (Reveal & Reveal 725, BRY, UTC), and Wasatch County (Goodrich 16099, BRY) in northeastern Utah, and from Sweetwater County, Wyoming (Porter & Porter 10510, BRY, RM; Reveal & Reveal 2935, BRY, UTC). Given the limited distribution of E. corymbosum in Wyoming (Sweetwater County), it is considered a “species of concern” in that state.