Colorado Four O'clock

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).

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.

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

Quamoclidion multiflorum Torr.; A. Gray, Am. Jour. Sci. II
15: 321. 1853.
Oxybaphus multiflorus Torr. Ann. Lye. N. Y. 2: 237. 1827.
Allionia multiflora Eaton, Man. ed. 6. 11. 1833.
Nyctaginia ? Torr ey ana Choisy, in DC. Prodr. 13 2 : 430. 1849.
Mirabilis multiflora A. Gray, in Torr. Bot. Mex. Bound. Surv. 173. 1859.
Quamoclidion multiflorum glandulosum Standley, Contr. U. S. Nat. Herb. 12: 359. 1909.
Quamoclidion multiflorum obtusum Standley, Contr. U. S. Nat. Herb. 12: 359. 1909.
Mirabilis multiflora glandulosa F. Macbr. Contr. Gray Herb. 49: 49. 1917.
Mirabilis multiflora obtusa F. Macbr. Contr. Gray Herb. 49: 49. 1917.
Plants erect or ascending, 3-6 dm. high, much branched, often forming clumps a meter in diameter, the branches usually stout, densely leafy, glaucous or glaucescent, obscurely
puberulent or finely shortvillous and viscid, often glabrate; petioles slender or stout, 0.4—3.5 cm. long; leaf-blades broadly ovate-deltoid to reniform-orbicular or ovate-oblong, 2.5-7.5 cm. long, 1.5-7.5 cm. wide, cordate to rounded at the base and often short-decurrent, broadly rounded and apiculate to very acute at the apex, thick and succulent, glaucescent, glabrous to puberulent or shortvillous and viscid or glandular-puberulent ; peduncles slender or stout, 0.5-6 cm. long, solitary in the axils and cymosely clustered at the ends of the branches, the leaves of the inflorescence reduced; involucre campanulate, usually 6-8 flowered, 1.6-3.5 cm. long, glabrous, glandular-puberulent, or short-villous and viscid, green or tinged with red, the 5 lobes equaling or usually shorter than the tube, ovate-orbicular to triangular, rounded
and apiculate to very acute; perianth purplish-red, 4-5.5 cm. long, glabrous or glandular-
puberulent outside, the tube 4-7 mm. thick, expanding into a shallowly 5-lobed limb 2.5-3
cm. broad; stamens equaling the perianth or usually slightly exserted; fruit elliptic-oblong in
outline, narrowed at both ends, 8-10 mm. long, dark-brown to nearly black, smooth, glabrous.
Type locality : About the forks of the Platte River, Colorado.
Distribution: In dry, chiefly sandy soil, southern Utah and Colorado to northern Chihuahua and western Texas.

Quamoclidion multiflorum Torr.; A. Gray, Am. Jour. Sci. II
15: 321. 1853.
Oxybaphus multiflorus Torr. Ann. Lye N. Y. 2: 237. 1827.
Allionia multiflora Eaton, Man. ed. 6. 11. 1833.
Nyctaginia ? Torreyana Choisy, in DC. Prodr. 13 2 : 430. 1849.
Mirabilis multiflora A. Gray, in Torr. Bot. Mex. Bound. Surv. 173. 1859.
Quamoclidion multiflorum glandulosum Standley, Contr. U. S. Nat. Herb. 12: 359. 1909.
Quamoclidion multiflorum obtusum Standley, Contr. U. S. Nat. Herb. 12: 359. 1909.
Mirabilis multiflora glandulosa F. Macbr. Contr. Gray Herb. 49: 49. 1917.
Mirabilis multiflora obtusa F. Macbr. Contr. Gray Herb. 49: 49. 1917.
Plants erect or ascending, 3-6 dm. high, much branched, often forming clumps a meter in diameter, the branches usually stout, densely leafy, glaucous or glaucescent, obscurely puberulent or finely short-villous and viscid, often glabrate; petioles slender or stout, 0.4-3.5 cm. long; leaf -blades broadly ovate-deltoid to reniformorbicular or ovate-oblong, 2.5-7.5 cm. long, 1.5-7.5 cm. wide, cordate to rounded at the base and often short-decurrent, broadly rounded and apiculate to very acute at the apex, thick and succulent, glaucescent, glabrous to
puberulent or short-villous and viscid or glandular-puberulent ; peduncles slender or stout, 0.5-6 cm. long, solitary in the axils and cymosely clustered at the ends of the branches, the leaves of the inflorescence reduced; involucre campanulate, usually 6-8 flowered, 1.6-3.5 cm. long, glabrous, glandular-puberulent, or short-villous and viscid, green or tinged with red, the 5 lobes equaling or usually shorter than the tube, ovate-orbicular to triangular, rounded and apiculate to very acute; perianth purplish-red, 4-5.5 cm. long, glabrous or glandularpuberulent outside, the tube 4-7 mm. thick, expanding into a shallowly 5-lobed limb 2.5-3 cm. broad; stamens equaling the perianth or usually slightly exserted; fruit elliptic-oblong in outline, narrowed at both ends, 8-10 mm. long, dark-brown to nearly black, smooth, glabrous.
Type locality : About the forks of the Platte River, Colorado.
Distribution: In dry, chiefly sandy soil, southern Utah and Colorado to northern Chihuahua and western Texas.

Mirabilis multiflora is a species of flowering plant in the four o'clock family known by the common name Colorado four o'clock that is native to the southwestern United States from California to Colorado and Texas, as well as far northern Mexico, where it grows in mostly dry habitat types in a number of regions.