Euphorbia albomarginata
Pacif. Railr. Rep. 2(4): 174. 1857.
Herbs, perennial, with moderately to strongly thickened rootstock. Stems prostrate, occasionally mat-forming, frequently rooting at nodes, 10–80 cm, glabrous. Leaves opposite; stipules connate into conspicuous, deltate or ovate scale, white, 0.4–1(–2) mm, glabrous; petiole less than 1 mm, glabrous; blade ovate, oblong or orbiculate, 3–8(–15) × 3–7 mm, base strongly asymmetric, obtuse to hemicordate, margins whitish, entire, apex obtuse, rarely mucronulate, surfaces often with red blotch in center, glabrous; 3-veined from base but usually only midvein conspicuous. Cyathia solitary at distal nodes; peduncle 1–4 mm. Involucre campanulate, 0.8–1.1 × 0.9–2 mm, glabrous; glands 4, greenish yellow to red, usually oblong to reniform, rarely subcircular, 0.2–0.5 × (0.2–)0.3–0.8 mm; appendages white to pink, flabellate to oblong, 0.3–1 × 0.6–1.3 mm, distal margin entire or crenulate to erose. Staminate flowers 15–30. Pistillate flowers: ovary glabrous; styles 0.3–0.7 mm, 2-fid nearly entire length. Capsules broadly ovoid, 1.1–2.3 × 1.2–2 mm, glabrous; columella 1.1–1.6 mm. Seeds white to gray or brownish red, oblong-ovoid, 4-angled in cross section, 1–1.7 × 0.5–0.8 mm, smooth.
Phenology: Flowering and fruiting year-round.
Habitat: Disturbed areas in desert scrub, grasslands, mesquite woodlands, chaparral.
Elevation: 0–2300 m.
Distribution
Ariz., Calif., Colo., Nev., N.Mex., Okla., Tex., Utah, Mexico, introduced in Pacific Islands (Hawaii).
Discussion
Euphorbia albomarginata is native to northern and central Mexico and the southwestern and south-central United States. The species occurs in a variety of habitats in western North America and in some areas is quite weedy. It has been recorded as a waif in Louisiana.
Selected References
None.