Sweet Four O'clock

A. Le Duc (1995) and B. L. Turner (1993b) recognized two varieties, Mirabilis longiflora var. longiflora, restricted to the Mexican trans-volcanic belt, and var. wrightiana found from central Mexico to the southwestern United States. Recent United States floras have recognized only the var. wrightiana, both varieties, or have not recognized infraspecific taxa north of the Mexican border. Characters used to distinguish the varieties are thoroughly mixed. H. M. Hernández (1990) found an absence of insect visitors in this apparently sphingid-adapted species, with the plants self-compatible and probably highly autogamous.

Stems usually several, 5-15 dm; herbage lightly puberulent basally, glandular-puberulent [glandular-villous] distally. Leaves at midstem with petiole 2-6 cm; blade usually cordate, less often deltate, ovate, or ovate-lanceolate, 5-14 × 3-8 cm. Inflorescences dense clusters of flowers among conspicuous foliaceous bracts 5-20 mm; peduncle 0.5-2 mm; bracts 40-60% connate, 7-11 mm in flower, 10-18 mm in fruit, apex triangular to narrowly triangular. Flowers: perianth white, tube blushed with green or purple, (7-)8-15(-17) cm, pubescent externally. Fruits black to dark brown, bluntly 5-angled in cross section, with low black to dark brown [white] irregular tubercles between angles, ovoid to slightly obovoid, 7-12 mm, base abruptly constricted to truncate, apex tapered to truncate, puberulent between tubercles. 2n = 58.

Ariz., N.Mex., Tex.; Mexico; introduced in Europe.

Flowering summer-early fall.

Rocky canyons and slopes; 800-2300[-2700]m.

Mirabilis longiflora var. wrightiana (A. Gray ex Britton & Kearney) Kearney & Peebles

Mirabilis longiflora L. Sv. Vet.-Akad. Handl. 1755: 176. 1755
Jalapa longiflora Moench, Meth. 508. 1794.
Nyctago longiflora Salish. Prodr. 57. 1796.
Mirabilis suaveolens H. B. K. Nov. Gen. & Sp. 2: 213. 1817.
Plants erect, 5-15 dm. high, much branched, the branches erect or ascending, slender, densely viscid-puberulent or short-villous, the internodes usually longer than the leaves; petioles slender, usually less than 1 cm. long but rarely 4.5 cm. long in the lowest leaves, the upper leaves sessile or subsessile; leaf-blades cordate-ovate to narrowly deltoid-ovate or lanceovate, 6-11.5 cm. long, 3-7 cm. wide, cordate at the base, acute to long-attenuate at the apex, usually subabruptly so, thin, bright-green, densely viscid-puberulent or rarely glabrate; inflorescence of numerous dense, axillary or terminal, leafy glomerules, these sometimes subtended by long linear bractlike leaves; involucres on peduncles 3 mm. long or usually shorter, campanulate, 1-1.5 cm. long, densely glandularvillous with short hairs, the lobes slightly unequal, equaling or exceeding the tube, triangular to narrowly triangular-lanceolate, very acute to long-attenuate; perianth 7-17 cm. long, densely viscidvillous outside, white tinged with pink or purplish-red, the tube very slender, about 2 mm. in diameter, abruptly expanded into a shallowly 5-lobed limb 2-3 cm. broad; stamens 5, exserted 2.5 cm. or less; fruit oblong, ellipsoid, 8 mm. long, 5 mm. in diameter, constricted at both ends, obtusely 5-angled, tuberculate, densely puberulent between the tubercles.
Type locality* IVIcxico.
DistributionWestern Texas to southern Arizona, southward to Veracruz and Oaxaca.

Mirabilis wrightiana A. Gray; Britton & Kearney, Trans. N. Y
Acad. 14: 28. 1894.
Plants erect, 6-12 dm. high, much branched, the branches erect or ascending, slender, minutely puberulent and scarcely or not at all viscid, glabrate below; petioles slender, 1-6 cm. long, the uppermost blades usually short-petiolate, very rarely subsessile; leaf-blades broadly cordate-ovate to narrowly ovate-deltoid, 5-12.5 cm. long, 2-8 cm. wide, cordate to truncate at the base and often short-decurrent, rather abruptly acute to long-attenuate at the apex, thin, bright-green, minutely puberulent or in age glabrate, minutely ciliolate; inflorescence of numerous dense terminal headlike cymes, these subtended by leaves or narrow bracts, the peduncles 3 mm. long or usually shorter; involucre campanulate, 1-1.5 cm. long, densely puberulent, slightly if at all viscid, the lobes about as long as the tube, narrowly to broadly triangular, very acute to long-attenuate; perianth white tinged with pink or purple, 10-14 cm. long, sparsely and minutely puberulent outside, the tube very slender, 2 mm. in diameter, abruptly expanded into a shallowly 5-lobed limb 2.5-3 cm. broad; stamens 5, exserted 3 cm. or less; fruit oblong-ellipsoid, 8 mm. long, 5 mm. in diameter, constricted at both ends, darkbrown, obtusely tuberculate, puberulent.
Type locality: Mexico.
Distribution: Southern Arizona to western Texas, Coahuila, and Sonora.

Mirabilis longiflora, the sweet four o'clock, is a species of flowering plant native to the southwestern United States from Arizona to Texas and northern Mexico. It is night-flowering. The flowers are mostly white, strongly scented, and long and narrow in form, approaching 17 centimeters in maximum length.