46. Eriogonum diatomaceum Reveal, J. Reynolds & Picciani, Novon. 12: 87, fig. 1. 2002.
Churchill Narrows wild buckwheat
Herbs, matted or slightly spreading, scapose, 0.5-2 × 0.5-2.5 dm, tomentose, grayish. Stems spreading, with persistent leaf bases, up to 1/ 4 height of plant; caudex stems matted or slightly spreading; aerial flowering stems scapelike, erect, slender, solid, not fistulose, (0.4-)0.5-1.5(-2) dm, tomentose. Leaves sheathing up flowering stem (1.5-)2-4 cm, 1 per node, fasciculate in terminal tufts on stemless caudex branches; petiole (0.3-)0.5-1.5(-1.8) cm, tomentose; blade elliptic, (0.5-)0.8-2(-2.3) × (0.3-)0.5-1.2(-1.8) cm, densely grayish-tomentose on both surfaces, margins plane. Inflorescences capitate, 1-1.5 cm wide; branches absent; bracts 3-8, elongate-triangular to triangular, scalelike, 1-3 mm, tomentose. Peduncles absent. Involucres 5-10 per cluster, turbinate, (2.5-)3-4.5 × 2-3 mm, rigid, tomentose; teeth 5-7, erect, 0.6-1 mm. Flowers (1.5-)2.5-3 mm; perianth creamy white, glabrous; tepals connate proximal 1/ 1/ 2, monomorphic, oblong-ovate; stamens exserted, 3-3.5 mm; filaments sparsely pilose proximally. Achenes light brown, 2-2.5 mm, glabrous.
Flowering Jun-Sep. White, chalky slopes, saltbush communities; of conservation concern; 1300-1400 m; Nev.
Eriogonum diatomaceum is known only from a few scattered populations in the Churchill Narrows area south of Fort Churchill State Park in Lyon County, occurring on silty diatomaceous deposits of the Coal Valley Formation. It is considered a “sensitive” species in Nevada, and is also a candidate for federal endangered listing, U.S. Fish and Wildlife Service.