Colorado four-o’clock, Froebel’s four-o’clock

Oxybaphus multiflorus Torrey, Ann. Lyceum Nat. Hist. New York 2: 237. 1827; Quamoclidion multiflorum (Torrey) Torrey ex A. Gray

Herbs, forming hemispheric clumps 6-10 dm diam., glabrous or densely pubescent. Stems 4-7 dm. Leaves spreading; petioles of proximal leaves 2-4 cm; blades of midstem leaves ovate to widely ovate, sometimes suborbiculate, rarely reniform, 5-10 × 4-8 cm, base rounded to cordate, often asymmetric, apex acute or acuminate to obtuse, rarely rounded. Involucres: peduncle 4-75 mm; involucres erect or ascending, 33-35 mm; bracts 5, usually more than 50% connate, apex acute to obtuse or ovate. Flowers 6 per involucre; perianth magenta, funnelform, 2.5-6 cm. Fruits brown to black, with 10 slender, tan ribs alternating with 10 dark brown ribs, or ribs inconspicuous, ovoid or globose, 6-11 mm, smooth to rugulose, glabrous or pubescent, secreting mucilage or not when wetted. 2n = 66.

Varieties 3 (3 in the flora): w United States, n Mexico.

G. E. Pilz (1978) recognized three partially sympatric varieties based on presence or absence of mucilage production in the fruits, fruit color, and apical acuteness of involucral bracts. Overall, populations are poorly differentiated, and in some areas plants represent a "collage" (Pilz’s term) that combine characteristics of different varieties; S. L. Welsh et al. (1987) recognized no varieties. Mirabilis multiflora is used in the Southwest in a minor way in xeriscapes. Among indigenous peoples, it has been used as food and medicine (V. L. Bohrer 1975; L. S. M. Curtin 1947).