Mirabilis glabra (S. Wats.) Standl.
Family: Nyctaginaceae
smooth four o'clock,  more...
[Allionia carletonii Standl.,  more...]
Mirabilis glabra image
Britton, N.L., and A. Brown. 1913  

Stems erect or ascending, sparsely to moderately leafy mostly in proximal 2/3, narrowly forked, usually with main axis, 5-20 dm, glabrous, glandular-puberulent, or puberulent with curved hairs, when pubescent, hairs usually densest distally. Leaves strongly ascending at 5-25°, progressively reduced toward inflorescence; petiole 0-1.3 cm; blade glaucous or grayish green, linear to narrowly ovate or ovate-oblong, 5-10 × 0.2-7.5 cm, thick and somewhat coriaceous, base attenuate to obtuse, round, truncate, or subcordate, apex acute to obtuse, occasionally round, surfaces glabrous to short pilose. Inflorescences usually terminal, sometimes also with short branches in distal axils, open, with main axis and short branches; peduncle 5-10 mm, usually spreading glandular-pilose, sometimes merely puberulent or glabrous, crosswalls of hairs pale; involucres pale green, widely bell-shaped, 3-6 mm in flower, 7-12 mm in fruit, glabrous except for few small hairs on margins to spreading glandular-pilose, 60-90% connate, lobes broadly ovate, rounded. Flowers 1-3 per involucre; perianth white to pale pink, 0.6-0.9 cm. Fruits grayish to greenish brown (ribs usually paler), narrowly obovate and tapering at both ends, 4-5.5 mm, usually glabrous, sometimes very lightly puberulent with hairs 0.1 mm; ribs narrow and keel-like to acute or acute-rounded, 0.2-0.5 times width of sulci, 0.5 times as wide as high, smooth; sulci lightly to prominently tuberculate.

Flowering late spring-early fall. Sandy soils in grasslands or among oaks, juniper, or mesquite, disturbed areas; 500-2100 m; Ariz., Colo., Kans., Nebr., N.Mex., Okla., Tex., Utah; Mexico (Chihuahua).

As traditionally treated, Mirabilis carletonii (stems short pilose) and M. exaltata (stems glabrous), both from the eastern portion of the range of M. glabra, have leaves broader than 10 mm. Correlated with this is the presence of two to three flowers in the involucres. The narrower-leaved M. glabra, in the strict sense, has one or occasionally two flowers per involucre.

Martin and Hutchins 1980, FNA 2003, Allred and Ivey 2012, Correll and Johnston 1970

Duration: Perennial

Nativity: Native

Lifeform: Forb/Herb

General: Perennial herb, 50-200 cm tall; stems mostly erect, sparingly branched, glaucous (waxy) and glabrous to slightly strigose.

Leaves: Opposite and sessile or on petioles to 1.5 cm long; blades triangular-ovate to narrowly lanceolate or linear, 5-10 cm long and 2-75 mm wide, gray-green, thick, and often leathery.

Flowers: Pinkish, in terminal panicles with short lateral branches; each small cluster of 1-3 flowers is surrounded by a pale green bell-shaped involucre which is glabrous, 3-6 mm long in flower, and 7-12 mm long in fruit; petals fused into a bell-shape, 7-8 mm long, whitish to pale pink.

Fruits: Achenes gray-brown to green-brown and usually hairless, 4-5 mm long, narrowly obovate and 5-ribbed, the spaces between the ribs often warty; containing a single light brown seed, 3 mm long.

Ecology: Found on sandy soils, from 4,000-6,500 ft (1524-1981 m), flowers July-August.

Distribution: NE and e CO south to TX, NM, and n AZ.

Notes: This description follows FNA (2003) which lumps the wider-leaved M. carletonii into this taxon. M. glabra in the traditional sense has linear or linear-lanceolate leaves which are generally less than 1 cm wide, and a glabrous stem; look for it under Oxybaphus glaber in some older texts. M carletonii, as traditionally described, has sticky-hairy stems and leaves that range from lanceolate to triangular-ovate. Allred and Ivey (2012) follow FNA in lumping M. carletonii into M. glabra, and distinguish the species from others in the genus based on the glabrous or lightly puberulent, prominently 5-ribbed fruits; small flowers less than 2 cm long; and leaves ranging from linear-lanceolate to heart shaped, which are "mostly" more than 1 cm wide.

Ethnobotany: Unknown

Etymology: Mirabilis is Latin for miraculous or wonderful, alluding to the beauty of the plants; glabra means hairless or smooth.

Synonyms: Allionia carletonii, Allionia ciliata, Allionia exaltata, Allionia glabra, Mirabilis carletonii, M. ciliata, M. exaltata, Oxybaphus carletonii, O. exaltatus, O. glaber

Editor: SBuckley 2011, AHazelton 2017

Mirabilis glabra image
Britton, N.L., and A. Brown. 1913