18. Eriogonum hylophilum Reveal & Brotherson, Great Basin Naturalist. 27: 190. 1968.
Gate Canyon wild buckwheat
Eriogonum corymbosum Bentham var. hylophilum (Reveal & Brotherson) S. L. Welsh
Subshrubs, spreading, not sca-pose, 2.5-4 × 3-5 dm, tomentose, greenish. Stems spreading, often with persistent leaf bases, up to 1/ 4 or more height of plant; caudex stems somewhat matted; aerial flowering stems erect or nearly so, somewhat stout, solid, not fistulose, 0.5-1.5 dm, tomentose. Leaves cauline and sheathing proximal 3 of stem, 1 per node; petiole 0.5-1(-1.8) cm, tomentose; blade linear-lanceolate to lanceolate, 3.5-7(-9) × 0.3-0.6(-0.8) cm, densely white-tomentose abaxially, less so and greenish adaxially, margins plane and slightly revolute, rarely crenulate. Inflorescences cymose, open, 3-8 × 3-10 cm; branches dichotomous, tomentose; bracts 3, scalelike, triangular, and 2-3 mm, or leaflike, 1-2 cm, and similar to leaf blades. Peduncles absent. Involucres 1 per node or 2-3 per cluster, turbinate, 3.5-4 × 2.5-3 mm; teeth 5-6, erect, 0.5-1 mm. Flowers (3-)3.5-4(-4.5) mm; perianth white, glabrous; tepals connate proximal 1/ 4, slightly dimorphic, those of outer whorl spatulate, 1-3-1.7(-2) mm wide, those of inner whorl oblanceolate, 0.6-0.9(-1.2) mm wide; stamens included, 2-3(-3.5) mm; filaments pilose proximally. Achenes brown, 2.5-3 mm, glabrous except for slightly papillate beak.
Flowering Jul-Sep. Gravelly slopes, sagebrush communities, pinyon-juniper or montane conifer woodlands; of conservation concern; 2200-2600 m; Utah.
Eriogonum hylophilum is known from a few, scattered locations in the Gate Canyon area and just west along the rim of the Badland Cliffs in Duchesne County. The species is closely related to E. corymbosum and approaches the minor segregate of the latter known as var. erectum. It is possible that the Gate Canyon wild buckwheat has an evolutionary history involving that expression of E. corymbosum and the white- to cream-colored flower expression of E. brevicaule var. laxifolium. If so, E. hylophilum is a stable and persistent taxon of hybrid origin.