NYCTAGINACEAE the Four-o'clock Family(to Genus key)

Family characters: Annual, biennial, or perennial herbs, usually from a woody or fleshy taproot, some (but not ours) shrubs or trees. Stems variously procumbent to scandent or erect, commonly dichotomously or trichotomously branched, glabrous to pubescent, often with swollen nodes; producing betalain pigments and not anthocyanins. Leaves opposite, simple, petiolate to sessile, estipulate. Flowers generally perfect or sometimes functionally unisexual and the plants dioecious; flowers regular sometimes dimorphic or heterostylous, usually arranged in corymbose or panicoid cymes, sometimes solitary, racemose, spicate, capitate, or umbellate; inflorescence often subtended by an involucre of free or united bracts, these herbaceous or petalloid, often persistent and accrescent in fruit; sometimes the inflorescence reduced to a single flower and giving the appearance of one large flower with calyx-like bracts and a petalloid calyx. Calyx petalloid, of (3)5(8) fused sepals, tubular to funnelform or campanulate, plicate to valvate in bud, deciduous or persistent, the base often becoming hardened and enclosing the fruit (in some genera, e.g. Mirabilis, with 1-flowered inflorescences, the result is a flower with calyx-like bracts below the fruit and a corolla-like calyx above); true corolla none. Stamens (1) as many as the calyx lobes or sometimes as many as 30, hypogynous, filiform, unequal, often connate basally. Gynoecium included in the corolla tube but superior (appearing inferior in species where the calyx base hardens around the ovary), unicarpellate and unilocular; style 1, elongate, slender, stigma commonly capitate to peltate, ovule 1, nectary disk sometimes present around the ovary. Fruit an achene or nut, often enclosed by the hard or leathery calyx base and termed an anthocarp, fruits often clustered in the involucre. Seed often with starchy perisperm.

About 350 species in 45 genera in warm and tropical regions, especially in the Americas, a few in temperate regions. There are 13 genera and 69 species in TX; 3 genera and 8 species in our area, including 1 endangered species.

Most members of the Nyctaginaceae are not economically important. A few have medicinal or food value. Some, notably Mirabilis (Four-o'clock) and Bougainvillea, are cultivated for ornament.

NYCTAGINACEAE - Key to Genera:



1. ABRONIA Juss. Sand Verbena

Annual or perennial herbs; stems prostrate to erect, branched; sometimes clumped and seemingly acaulescent; pubescent, often viscid. Leaves petiolate, opposite, the two of a pair often of different sizes, blades succulent, entire to sinuate. Flowering stems sometimes scapose; flowers perfect, few to many in long-pedunculate heads subtended by 5 conspicuous, scarious, usually distinct bracts; perianth funnelform to salverform, tube elongate, slender, and commonly constricted above the ovary; limb 5-lobed, often withering and persisting. Stamens usually 5, included. Ovary ovoid, style filiform and stigma linear or fusiform, included. Fruit turbinate to biturbinate, deeply 2- to 5-lobed or -winged, leathery, hardened, or papery. Embryo with one cotyledon aborted.

About 36 species of N. Amer; 5 species in TX (2 listed in Correll and Johnston since transferred to Tripterocalyx); 2 species here, one endangered.

Some species, especially A. fragrans, are cultivated as ornamentals.

Key to Abronia Species:

(to Genus key)



1. A. macrocarpa L. A. Galloway Large-fruited Sand Verbena. Perennial herb from a long, fleshy to semi-woody taproot. Stems to 50 cm tall, ascending to semi-erect, glandular-viscid pubescent. Petioles 0.5 to 4 cm long, blades ovate to elliptic or rotund, 2 to 5 cm long, 1.5 to 3.5 cm broad, entire, viscid-pubescent. Floral bracts ovate to elliptic, 7 to 13 mm long, 4 to 6 mm broad; flowers 20 to 45(75) per head, heads to ca. 10 cm broad; flowers magenta, 18 to 30 mm long, tubular, limb 5-lobed, 4 to 10 mm broad, fragrant. Anthocarps turbinate, papery, scarious, 5- winged, somewhat notched at the apex, 8 to 15 mm long, 5 to 12 mm broad. Seeds fusiform, 2 to 4 mm long, lustrous. Bare, wind-blown sand dunes surrounded by post oak woodlands. Known only from small areas of Leon and Robertson Cos. First collected in 1971, described in 1972. On Federal and State endangered species lists. Late Mar.-early June.

2. A. ameliae Lundell Amelia's Sand Verbena. Coarse perennial herb; stems to 60 cm high or long, spreading, thick viscid-glandular pubescent and villous with hairs of variable length; somewhat grooved when dry. Petioles 1 to 8.5 cm long, those of the lower leaves longer than the blades; blades ovate to elliptic or orbicular, 3 to 8 cm long, 2 to 6 cm broad, apices rounded, bases subcordate to subtruncate, decurrent at the base, margins noticeably sinuate, fleshy, leaves drying stiff and brittle, sparsely short viscid-pubescent above and below. Peduncles 2.5 to 13 cm long, slender, viscid-puberulent. Floral bracts 5 to 7, thin, oblong to elliptic or obovate, 10 to 16 mm long, 5 to 10 mm broad, apex broadly rounded and acute, greenish to pale magenta, externally viscid-villous. Heads many-flowered, to 5 cm broad; flowers with perianths orchid/pale magenta, 18 to 25 mm long, villous-viscid, tube slender, limb to 1 cm broad, 5-lobed, the lobes emarginate. Stamens 5, included. Anthocarp narrowly turbinate, apex rounded to truncate, not narrowed, attenuate at the base, 7 to 9 mm long, 3 to 4.5 mm broad, 5-winged, reticulate-veined, glabrous to sparsely pubescent at the apex. Seeds oblong-oblanceolate, ca. 2.5 mm long. Sandy areas along roadsides in post oak belts. Rio Grande Plains to the Panhandle, reported as far E. as Leon Co.; endemic. Mar.-Jun.

2. BOERHAVIA L. Spiderling

Annual or perennial herbs; stems sprawling or trailing, branched, sometimes diffuse, radiating from a central crown, variously pubescent or glandular, internodes often villous. Leaves opposite, the two of each pair unequal, usually paler beneath, entire to sinuate, often acute. Flowers to 1.5 cm broad, perfect, not in involucres but each flower bracted, in cymose panicles or racemes, pedicels jointed just below the ovary. Calyx corolla-like, campanulate to nearly rotate, constricted above the ovary, limb deciduous, shallowly 5-lobed. Stamens 1 to 5, exserted or inclined, filaments of different lengths, connate below. Ovary stipitate, style filiform and stigma peltate. Anthocarp ovoid or obpyramidal, with 3 to 5 angles or, less commonly, 5 to 10 ribs, rarely with 3 to 5 wings, glabrous to pubescent. Seed with a curved embryo. Boerhavia is Linnaeus' original spelling, but the name Boerhaavia appears in many works.

About 40 species, primarily tropical and subtropical; 11 in TX with the inclusion of formerly-separate Commicarpus scandens (L.) Standl. as B. scandens L. Two species are found in our area.

A few are used in medicines or as food, but not ours. Some are weedy.

Key to Boerhavia Species:

(to Genus key)

  • 1. Anthocarp glandular, narrowly obovoid, rounded at the apex ..1. B. diffusa
  • 1. Anthocarp eglandular, narrowly obpyramidal, truncate at the apex ..2. B. erecta

    1. B. diffusa L. Scarlet Spiderling. Perennial from a fleshy or woody, sometimes stout root; stems few to many, decumbent, procumbent, or ascending, sparingly branched below, 2 to 15 dm long, brown or herbaceous; lower portions minutely puberulent to viscid- pubescent, especially near the nodes; upper portions densely glandular-puberulent to somewhat viscid or even glabrate. Petioles 3 to 40 mm long, commonly villous; blades thin or rarely leathery, suborbicular or widely ovate to ovate-oblong, 1.5 to 5.5 cm long, 8 to 50 mm broad, bases subcordate to rounded or truncate, apices rounded to acute, margins entire to sinuate, paler beneath, brown-punctate or not, glabrous to minutely puberulent, margins villous-ciliate; lower surface with veins sparsely villous, sometimes the entire leaf densely hirsute or hirtellous. Flowers in lax, much-branched terminal and axillary cymes, branches divergent or ascending and glabrous to puberulent or glandular. Involucres absent. Flowers sessile to short-pedicelled, in clusters of 2 to 4 at the ends of slender peduncles 3 to 10 mm long. Floral bracts minute, less than 2 mm long, deciduous or persistent, ovate or lanceolate, viscid-puberulent. Perianths purple-red to red-green, limb 2 mm broad, all minutely glandular-puberulent; stamens 1 to 3, briefly exserted. Anthocarp narrowly obovoid, rounded at the apex, 2.5 to 4 mm long, densely glandular-puberulent (or glandular-pilose), 5-ribbed or -angled, angles and grooves smooth. Waste places, fencerows, riverbanks, fields, etc. S. and W. TX; W. FL to TX, and SE. CA; Mex. through Cen. Amer. to N. and W. S. Amer., also W.I. and Caribbean; adventive elsewhere, including once in NC. July-Nov. [B. coccinea Mill., B. caribaea Jacq.].

    2. B. erecta L. Erect Spiderling. Taprooted annual or perennial; stems erect to decumbent, usually branched at the base, 2 to 12 dm long or tall, branches spreading or decumbent, sometimes red-tinged; lower portions finely pubescent, middle internodes often with viscid brown bands; upper portions glabrous or minutely puberulent. Petioles 4 to 40 mm long, ca. 1/2 the length of the blades; blades ovate-rhombic or ovate-deltoid, or the upper ovate-lanceolate to linear, 2 to 8 cm long, 1.4 to 5 cm broad, apices acute or obtuse to rounded, apiculate; bases truncate to rounded or somewhat cuneate; margins entire to undulate or repand; both surfaces usually brown-punctate, glabrescent, lower surface paler than upper (or glaucous.) Inflorescences axillary and terminal, cymose, umbellate, or somewhat racemose, usually well-branched, branches filiform, erect to ascending, usually glabrous but sometimes viscid. Involucre absent. Flowers in clusters of 2 to 6 on slender peduncles, pedicels 1 to 5 mm long. Floral bracts linear to lanceolate, reddish, 0.6 to 1.2 mm long, persistent. Perianths white or tinged with pink to purple, 1 to 1.5 mm long, tube glabrous or glandular-punctate, limb campanulate, sparsely pubescent. Stamens 2 or 3, exserted. Anthocarp green or yellow-green, primarily glabrous, narrowly obpyramidal, 3 to 4 mm long, 1 to 1.5 mm broad, apex truncate, 5- angled, the angles obtuse to acute, smooth, the grooves between coarsely cross-rugose. Dry fields, banks, waste places, and in cultivated ground. SC and FL W. to TX, AR, and S. AZ, S. through Mex. and Cen. Amer. to N. S. Amer., also W.I. and Caribbean. Spring to fall.

    3. MIRABILIS L. Four-o'clock

    ..Perennial herbs, usually from large tuberous roots; stems erect to ascending or sprawling, simple or branched from the base, branches forking, nodes often swollen; foliage glabrous to pubescent, glandular, or hispid. Leaves opposite, often fleshy, sessile to petiolate, variously-shaped, glabrous to pubescent or glaucous. Involucres terminal or axillary or both, in loose or congested cymose arrangements or involucres solitary in the axils. Involucres each with 1 to 10 flowers, 5-lobed, lobes equal or unequal, calyx-like, green or tinged with red or purple, more or less campanulate, in some species accrescent and papery in fruit, usually becoming rotate and noticeably veined. Flowers perfect, regular, calyx colored and corolla-like, tube elongate and constricted above the ovary, limb expanded, campanulate to salverform or funnelform, 5-lobed, deciduous in fruit but the perianth base persisting and becoming hardened around the ovary. True corolla absent. Stamens 3 to 6 (sometimes more), unequal, filiform, united at the base, anthers exserted. Ovary superior, unicarpellate, style filiform and stigma capitate. fruit a 1-seeded anthocarp (ovary enclosed by the leathery remnants of the calyx), 5-angled or 5-ribbed, surfaces smooth to tubercled, glabrous to pubescent. Seed filling the pericarp, pericarp fused to the testa; endosperm mealy.

    ..About 45 to 60 species of warm parts of the Americas, especially SW. N. Amer.; 29 species listed for TX; 4 from our area. Positive identification often requires mature fruits, and those species from section Oxybaphus form a complex group without clear specific circumscriptions.

    ..Some, notably M. jalapa, are grown for ornament; a few are used for dyes or in cosmetics or medicines. The tuberous roots of some are edible.

    Key to Mirabilis Species:

    (to Genus key)