Smith's wild buckwheat

Eriogonum corymbosum Bentham var. smithii (Reveal) S. L. Welsh

Shrubs, erect to spreading, not scapose, (3-)4-10 × 5-20 dm, glabrous, bright green. Stems spreading, without persistent leaf bases, up to 1/ 3 height of plant; caudex stems absent; aerial flowering stems erect to spreading, slender, solid, not fistulose, 0.2-2 dm, glabrous. Leaves cauline on proximal 2/ 3 of stem, 1 per node; petiole 0.3-0.5 cm, floccose or glabrous; blade narrowly elliptic, 2.5-4.5 × (0.3-)0.6-1 cm, glabrous and green on both surfaces, rarely thinly floccose adaxially, margins occasionally slightly revolute. Inflorescences cymose, open to compact, 2-25 × 3-35 cm; branches often with involucres racemosely arranged at tips of inflorescence, glabrous; bracts 3, scalelike, linear to triangular, 1.5-4.5 mm. Peduncles absent. Involucres 1 per node, turbinate, (2.5-)3-3.5 × 2-2.5 mm, glabrous; teeth 5, erect, 0.3-0.5 mm. Flowers 3-4 mm; perianth yellow, glabrous; tepals connate proximal 4, slightly dimorphic, those of outer whorl obovate, 1.5-2 mm wide, those of inner whorl oblanceolate, 1-1.5 mm wide; stamens exserted, 2-5(-7) mm; filaments pilose proximally. Achenes brown, 3-3.5 mm, glabrous except for minutely papillate beak. 2n = 40.

Flowering Jul-Oct. Deep, moving, red blow sand, mixed grassland and scrub oak communities; of conservation concern; 1400-1900 m; Utah.

Eriogonum smithii is restricted to the San Rafael Desert of Emery and Wayne counties. Plants from Little Gilson Butte (J. L. Anderson 86-228, BRY) have leaf blades thinly floccose on the abaxial surface but are otherwise similar to the shrubs found at Flat Top to the east. Smith's wild buckwheat occurs in selenium-rich sands, which may limit its ability to be cultivated. The bright green, brilliantly yellow-flowered plants would make an elegant addition to the garden.