11. Eriogonum ripleyi J. T. Howell, Leafl. W. Bot. 4: 5. 1944.
Ripley's wild buckwheat
Subshrubs, sprawling to decum-bent, occasionally scapose, 0.5-2.5(-4) × 0.5-5(-7) dm, grayish-tomentose. Stems decumbent to slightly spreading or erect, often with persistent leaf bases, up to 4 height of plant; caudex stems absent or compact; aerial flowering stems spreading to erect, slender, solid, not fistulose, 0.05-2.5(-3.5) dm, tomentose. Leaves cauline, 1 per node or fasciculate; petiole 0.05-0.15 cm, villous; blade narrowly oblanceolate, 0.2-0.6 × 0.05-0.1 cm, densely white-tomentose abaxially, thinly floccose to villous adaxially, margins revolute. Inflorescences cymose-umbellate or capitate and reduced to single involucre; branches usually dichotomous, sometimes with secondaries suppressed, occasionally absent, tomentose; bracts absent. Peduncles erect, 0.1-1.5 cm, thinly floccose. Involucres 1 per node, campanulate, 3-3.5 × 3-3.5 mm, thinly floccose or villous to subglabrous; teeth 3-5, erect, 0.7-1 mm. Flowers 3.5-4.5 mm; perianth white, glabrous; tepals connate proximal 1/ 5, dimorphic, those of outer whorl nearly orbiculate, 3-3.5 mm wide, those of inner whorl broadly obovate, 2-2.5 mm wide; stamens long-exserted, 4-5 mm; filaments villous to densely pilose proximally. Achenes light brown, 2-2.5 mm, glabrous.
Flowering Mar-Jun. Sandy clay flats and slopes on edge of sandstone outcrops, oak-juniper woodlands; of conservation concern; 1000-1900 m; Ariz.
Eriogonum ripleyi is known only from two areas in Arizona, one near Frazier's Well in Coconino County and a second in the Verdi Valley area of southeastern Yavapai and extreme northwestern Maricopa counties. The species is worthy of cultivation. Ripley's wild buckwheat is considered a “sensitive” species in Arizona.