Herbs (shrubs or trees) with tumid joints, entire and opposite leaves. Flowers surrounded with an involucre (calyx-like when the flower is solitary). Calyx a delicate, colored, funnel-form or tubular perianth, deciduous above the 1-eelled, 1-seeded ovary, leaving its persistent base to harden and envelop the fruit (achenium) as a kind of pericap. Stamens 1 to several, definite, slender, hypogynous, exserted, unequal. Embryo coiled around the copious white albumen. Fig. 373, 460.
Genera 16, species 110, chiefly tropical,south of the equator.
Properties. - The roots are purgative, especially those of the beautiful cultivated genus - Four-o'clock.
* Involucre calyx-like, involving but a single, large flower.......................
* Involucre involving several (3 to 5) small flowers...................................
* Involucre none, the minute flowers with deciduous bracts.......................
1. MIRAB'ILIS, L. Marvel of Peru. Four-o'clock. (Lat mira-brilis, wonderful, admirable; a name well applied.) Involucre calyx-like, 5-lobed, 1-flowered, lobes acuminate; perianth (calyx) tubular-funnelform, limb spreading; stamens 5, scarcely with the style exserted; achenium enveloped in the persistent base of the calyx. - Herbs mostly Mexican and Peruvian, everywhere cultivated.
1 M. Jalapa L. Erect; lvs. ovate, acuminate, base obtuse or subcordate, pe-tiolate, glabrous; fls. 3 to 6 in each terminal fascicle, short-stalked; perianth open in the evening and night - This is the true Four-o'clock, opening its multitudinous brilliant flowers at about that hour P. M., for a long succession of summer days. Their variety in color is infinite, † Peru.
2 M. dichotoma L. Erect, glabrous; lvs. ovate, subacuminate, base obtuse or narrowed to the petiole; fls. sessile or nearly so; lobes of invol. ovate-acute , perianth strict, with a small scarcely dilated limb. - Gardens, less frequent Fls. smaller, yellow, red and white, † Mexico.
3 M. longiflora L. Weak, diffuse, viscid-pubescent; lvs. cordate-acuminate, upper sessile, lower long-petioled; fls. sessile, clustered at apex; invol lobes linear; lube of the perianth very long, pubescent - Gardens. Fls. white, † Mexico.
3. OXYB'APHUS, Vahl. (Gr. a shallow cup or saucer; alluding to the form of the involucre.) Involucre 5-cleft, containing 3 to 5 flowers (in one species), persistent and spreading in fruit; perianth with a very short tube, and a plicate, bell-shaped, deciduous limb; stamens 3; style simple, stigma capitate; fruit ovoid, ribbed, 1-seeded. - Herbs with tuberous roots, opposite lvs. and small fls. (Caly-menia, Allioni.)
1 O. uyctagineus Sweet. Nearly smooth, erect, with alternate or forked branches; lvs. broadly ovale or oblong, subcordate, acute; peduncles solitary, axillary and terminal; invol. pubescent, 3 to 5-flowered. - Alluvial soils, Wis. to Tenu., rare; common in Nebraska. (Nuttall)
2 O. angustifolius Sweet. St. terete, puberulent above, with alternate branches. lvs. narrowly lanceolate, thick but veiny, entire or serrulate, acute, narrowed to the subsessile base; ped. several times shorter than the leaves, axillary and terminal; invol. 3-flowered, half-5-cleft, lobes broad, obtuse; ovary hispid. - Dry soils S. Car., Ga. to La. St. 2 to 3f high. Lvs. 2 to 3' by 5 to 9", or in some specimens (A. linearis Ph.) much narrower. Ped. 2 to 5" long. Cal. purplish. Jn.
3 O. albidus Sweet. St. angular, and pubescent in lines, simple; lvs. narrow, lance-oblong, acute at each end, petiolate; ped. solitary, axillary, half as long as the lvs.; invol. 2 to 3-flowered, deeply 5-cleft, segm. ovate, acute, ribs of fruit hispid. - Dry soils, S. Car., Ga. (Mettauer.) Sts. 12 to 18' high. Lvs. 2' to 30" long, 4 to 6" wide. Ped. 1' long, alternate, each with a whitish involucre 10" broad and 2 to 3 small fls. May. (A. alb. Ph.)
3. BOERHAA'VIA, L. (Dedicated to Bœrhaave, of Holland, a friend and patron of Linnseus.) Involucre 0; bractlets deciduous; perianth funnel or bell-form, colored, 5-lobed, upper half deciduous, lower persistent; stamens 1 to 4; fruit 5-ribbed, truncate at apex, 1-seeded. - Lvs. opposite, mostly petioled.
B. erecta L. Glabrous; lvs. ovate, wavy, pale beneath; fls. in a strict, much branched panicle. - Sandy soils, S. Car. to Fla. and La. St. 3 to 4f high, numerously dividing above into filiform, erect branchlets. Lvs. all below, 2' long, roundish at base, on petioles nearly as long. Fls. minute. Jn. - Sept.