Roundleaf Oxytheca

Oxytheca perfoliata is basically a plant of the Mojave Desert, with extensions along the Lahontan Trough into northwestern Nevada (to Humboldt and Washoe counties), and along the desert edge of California's Transverse Ranges and the more arid portions of the San Joaquin Valley. It also occurs in the Sonoran Desert south to Imperial County, California.

Oxytheca perfoliata is a food plant for the desert metalmark butterfly (Apodemia mormo deserti).

Plants spreading, 0.6-2 × 0.5-4 dm. Stems glandular distally. Leaf blades spatulate to oblong or oblanceolate, 1-6 × 0.3-1.5 cm, margins ciliate, otherwise gla-brous. Inflorescences open to densely branched, 0.8-1.7 dm; bracts at first node 4-5, triangular to lanceolate, 2-10 × 0.5-4(-8) mm, with awn 0.5-1 mm, sparsely glandular, bracts at remaining nodes 3, forming an orbiculate to somewhat triangular perfoliate disk mostly 1-2.5 cm across, glabrous or glandular, with awn 1-3 mm, terminal bracts 0.5-2 × 0.1-0.4 mm, sometimes merely acerose, with awn 0.5-2 mm. Peduncles erect, stout, 0.3-0.8 mm at proximal nodes, sometimes absent. Involucres 2-5 mm, glabrous or sparsely glandular abaxially; teeth 4; awns reddish, 2-3 mm. Flowers 5-10; perianth white or yellowish green to pink, 1.5-2.5 mm, echinulate and sparsely glandular abaxially; tepals monomorphic, lanceolate to ovate; filaments 1-1.5 mm, papillate basally; anthers pink to red, oval, 0.2-0.5 mm. Achenes dark brown to maroon, 1.5-2 mm. 2n = 40.

Ariz., Calif., Nev., Utah.

Flowering Apr-Aug.

Sandy to rocky flats, washes, and slopes mainly in saltbush communities; 600-1900m.

Eriogonum perfoliatum (Torrey & A. Gray) S. Stokes

Oxytheca perfoliata is a species of flowering plant in the buckwheat family known by the common names round-leaf puncturebract and roundleaf oxytheca. It is native to the southwestern United States, where it is a common plant of the deserts and some woodland and valley areas. It is an annual herb producing a leafless stem up to about 20 centimeters in maximum height in the spring; during the winter the plant is a small rosette of oblong or spoon-shaped leaves a few centimeters wide. The plant is red-veined green, or often brown to maroon or magenta in color. The inflorescence atop the stem is punctuated by nodes at which the bracts are fused to form a cup or band up to about 2.5 centimeters wide. At the end of each branching of the stem is a similar cup of bracts partially fused around a cluster of flowers. The bracts are tipped in spinelike awns. The flowers are white to yellow-green and hairy in texture.