79a. Eriogonum zionis J. T. Howell var. zionis
Zion wild buckwheat
Eriogonum racemosum Nuttall var. nobilis S. L. Welsh & N. D. Atwood
Plants erect to spreading, 3-8(-10) dm. Aerial flowering stems usually fistulose, glabrous or rarely tomentose. Leaf blades oblong-ovate to ovate, 2-4.5 × 1.5-2.5 cm. Inflorescences 20-45(-60) cm. Involucres 1.5-3 mm. Flowers 2-3.5(-4) mm; perianth white to yellow.
Flowering Jul-Oct. Deep sandy soil, sagebrush communities, scrub oak, juniper, pinyon, and montane conifer woodlands; 1300-2100 m; Ariz., Utah.
Variety zionis is found in scattered populations in Kane, San Juan, Washington, and Wayne counties, Utah, and in northern Coconino and northeastern Mohave counties, Arizona. It is rare or only locally infrequent. Occasionally, plants with tomentose flowering stems occur with glabrous individuals. The Zion wild buckwheat, with a chromosome number 2n = 40 (J. L. Reveal, unpubl.), is distinct from the related E. racemosum, with 2n = 36, and no intermediates are known.