107h. Eriogonum umbellatum Torrey var. haussknechtii (Dammer) M. E. Jones, Contr. W. Bot. 11: 6. 1903. (as hausknechtii).
Haussknecht's sulphur flower
Eriogonum haussknechtii Dammer, Gartenflora 40: 493, fig. 92. 1891 (as hausknecktii); E. umbellatum subsp. haussknechtii (Dammer) S. Stokes
Herbs, typically prostrate, sprawling mats, 0.5-1.5 × 1-4 dm. Aerial flowering stems spreading to erect, 0.3-0.6(-1.5) dm, thinly tomentose, without one or more leaflike bracts ca. midlength. Leaves typically in tight rosettes; blade usually broadly elliptic, 0.5-1.5(-2.5) × 0.5-1.2(-1.5) cm, tannish-tomentose abaxially, thinly tomentose or glabrous and olive green adaxially, margins plane. Inflorescences compact-umbellate; branches 0.1-1.5(-2) cm, thinly tomentose, without a whorl of bracts ca. midlength; involucral tubes 1.5-3.5 mm, lobes 1-4 mm. Flowers 2-6 mm; perianth bright yellow.
Flowering Jun-Sep. Volcanic, sandy to gravelly slopes and ridges, mixed grassland and sagebrush communities, montane to subalpine conifer woodlands; 1000-2500(-3100) m; Oreg., Wash.
Variety haussknechtii, as here circumscribed, is a high-elevation taxon found mainly on volcanic peaks in north-central Oregon (Benton, Clackamas, Hood River, and Wasco counties) and south-central Washington (Kittitas and Yakima counties). It is common on Mt. Hood and Mt. Adams. It typically grows with E. marifolium, and mixed collections often are found in herbaria; the two taxa have in common a distinctive olive green color of the adaxial leaf surfaces. Haussknecht's sulphur flower is not always clearly distinct from var. modocense. It is occasionally seen in cultivation, especially in European gardens.