Gard. Dict. ed. 8, Boerhavia no. 4. 1768.
Herbs, perennial, often ± woody at base; taproot long and ropelike, woody. Stems prostrate to decumbent, usually profusely branched throughout, 3–15 dm, minutely pubescent, often glandular, sometimes spreading villous or hirsute in basal portions, minutely pubescent, sometimes glandular, glabrate, or glabrous distally. Leaves usually distributed throughout plant and into much of inflorescence; larger leaves with petiole 5–25 mm, blade broadly lanceolate, ovate, or broadly ovate, occasionally ± round, 20–70 × 10–60 mm (distal leaves smaller, often proportionally narrower), base truncate, broadly cuneate, or round, rarely cordate, margins sinuate, apex acute to obtuse or round, adaxial surface glabrous or sometimes sparsely puberulent, rarely densely glandular-pubescent, abaxial surface paler than adaxial surface, glabrous or sometimes sparsely puberulent, rarely densely glandular-pubescent, often with large multicellular hairs along veins, neither surface punctate. Inflorescences axillary or terminal, forked unequally ca. 3–6 times, open, without sticky internodal bands; branches divergent, terminating in compact subumbellate or capitate 5-flowered clusters. Flowers: pedicel shorter than 0.5 mm; bract at base of perianth usually quickly deciduous, 1, linear-lanceolate to ovate, 0.5–1 mm; perianth maroon, or magenta (or rarely white or yellow) [pink], campanulate beyond constriction, 1–3.5 mm; stamens 2–3, slightly exserted. Fruits (2–)5–20(–30) per cluster, gray-brown to brown, narrowly obovate and tapering at both ends or clavate, 2.6–4 × 0.9–1.2 mm (l/w: 2.7–3.5), apex rounded to rounded-conic, moderately densely to densely stipitate-glandular on ribs and in sulci; ribs 5, rounded, smooth; sulci 1–2.5 times as wide as base of ribs, not rugose, not papillate. 2n = 52.
Phenology: Flowering spring–winter [year-round].
Habitat: Roadsides, weedy areas, upper beaches, rocky slopes, gravelly outwash fans, arroyos in tropical scrub, arid grasslands, desert scrub, pinyon-juniper woodlands
Elevation: 0-2000 m
Ala., Ariz., Calif., Fla., La., Md., Nev., N.Mex., N.C., S.C., Tex., Va., Mexico, West Indies, Central America, South America, Eurasia, Africa, Australia.
Boerhavia coccinea is weedy and probably adventive along the Gulf and southern Atlantic coasts in North America; it can be expected in waste areas anywhere in that region. Worldwide, it probably also has a broader range than indicated, particularly on oceanic islands. The complex, which is in need of taxonomic clarification, is extremely variable with regard to robustness, pubescence, and fruit number in individual terminal inflorescences. In the New World, flowers are usually some shade of deep wine red, although populations of white-flowered or yellow-flowered plants are rarely found (R. Spellenberg 2000). In the Old World, pink-flowered plants are frequent (C. Whitehouse 1996).