164. Eriogonum rubricaule Tidestrom, Proc. Biol. Soc. Wash. 36: 181. 1923.
Lahontan Basin wild buckwheat
Eriogonum laetum S. Stokes; E. trichopes Torrey var. rubricaule (Tidestrom) S. Stokes
Herbs, erect, annual, (0.5-)1-4(-8) dm, glabrous, green to yellowish green. Stems: caudex absent; aerial flowering stems erect, occasionally hollow and fistulose, 0.3-1.3(-2) dm, glabrous. Leaves basal; petiole 2-3(-4) cm, pilose-hispid; blade round to reniform, 1-2(-3) × (0.5-)1-3 (3.5) cm, pilose-hispid and bright green on both surfaces, margins plane. Inflorescences narrowly cymose, open, 5-30(-50) × 5-35 cm; branches occasionally fistulose, glabrous; bracts 3, scalelike, 1-4 × 0.5-2 mm. Peduncles erect or nearly so, straight, slender, 0.2-0.3 cm, glabrous. Involucres campanulate, 2.5-3 × 2.5-3 mm, glabrous; teeth 5, erect, 0.5-1 mm. Flowers 1.5-2 mm; perianth pale yellow to yellow with light green or reddish midribs, becoming yellowish red, glabrous, papillate in fruit; tepals monomorphic, narrowly ovate; stamens included to exserted, 1-2 mm; filaments glabrous. Achenes light brown, 3-gonous, 2-2.5 mm, glabrous.
Flowering May-Oct. Clayey, sandy or gravelly, often volcanic outcrops, washes, flats, and slopes, saltbush, greasewood, and sagebrush communities, pinyon-juniper woodlands; 1100-1800 m; Nev.
Eriogonum rubricaule occurs on the eastern half of the pluvial Lahontan Lake basin of northwestern Nevada (Churchill, Esmeralda, Humboldt, Lander, Lyon, Mineral, Nye, Pershing, and Washoe counties). It tends to occur on or near the old lakeshore at the bases of the mountains, where it is infrequent to locally common.