107d. Eriogonum umbellatum Torrey var. aureum (Gandoger) Reveal, Taxon. 17: 532. 1968.
Golden sulphur flower
Eriogonum glaberrimum Gandoger var. aureum Gandoger, Bull. Soc. Roy. Bot. Belgique 42: 195. 1906; E. neglectum Greene; E. umbellatum var. glabrum S. Stokes; E. umbellatum var. intectum A. Nelson; E. umbelliferum Small
Herbs, often rather compact mats, 1-3.5 × 2-6 dm. Aerial flowering stems erect, 1-2(-3) dm, thinly floccose or glabrous, without one or more leaflike bracts ca. midlength. Leaves in loose rosettes; blade usually elliptic, 1-2 × 0.5-1.5 cm, glabrous on both surfaces (except in central Idaho, where sparsely floccose even at full maturity), margins plane. Inflorescences umbellate; branches 0.3-2(-2.5) cm, without a whorl of bracts ca. midlength; involucral tubes 1.8-3 mm, lobes 1-3 mm. Flowers 4-7 mm; perianth bright yellow.
Flowering Jun-Sep. Sandy to gravelly or occasionally rocky flats and slopes, mixed grassland and sagebrush communities, pinyon and/or juniper and montane conifer woodlands; (1400-)1600-3200(-3400) m; Colo., Idaho, Mont., Nev., Oreg., Utah, Wyo.
Variety aureum is closely related to var. umbellatum, differing mainly in having glabrous leaf blades at full anthesis. However, var. aureum is much more widely distributed. At higher elevations, it is replaced by the weakly differentiated var. porteri. It is occasionally found in cultivation, especially in European gardens.