Plants perennial, finely pubescent, from stout taproots. Stems prostrate to erect, often clambering through other vegetation, slender to ± stout, herbaceous or woody, unarmed, without glutinous bands on internodes. Leaves sessile to petiolate, subequal to greatly unequal in each pair, ± thick and succulent, base asymmetric or ± symmetric. Inflorescences terminal or axillary, solitary flowers or few-flowered cymes and nearly sessile, or short pedicellate in 3–25-flowered umbellate clusters in axils or forks of branches; bracts persistent, not accrescent, 1–3 beneath each flower, distinct, narrowly lanceolate, small or minute, herbaceous. Flowers bisexual, chasmogamous and/or cleistogamous; cleistogamous perianth narrow domelike tube atop basal portion; chasmogamous perianth radially symmetric, short to elongate funnelform, constricted beyond ovary, abruptly expanded to 5-lobed limb; stamens 2(–3) or 5–6 (2–5 in cleistogamous flowers), exserted; styles exserted beyond anthers; stigmas peltate. Fruits oblong or narrowly ellipsoid, coriaceous, smooth, glabrous or minutely puberulent; ribs 5, rounded, often with large, dark, sticky gland near apex, or wings 3–5, coriaceous, hyaline, often between ribs or wings a rib or low sharp ridge.
sw United States, n Mexico, ne Africa.
Species 17 (12 in the flora).
R. A. Levin (2000) showed that Selinocarpus is paraphyletic and embedded within Acleisanthes. All species are pubescent on young stems and leaves. Older leaves may be glabrate or glabrous.
|1||Fruits with rounded or broadly obtuse ribs||> 2|
|1||Fruits with thin, hyaline wings||> 7|
|2||Resinous glands present at or near apex of fruits; overall glandular pubescence consisting of mixture of capitate hairs 0.2-0.3 mm, and shorter white, capitate hairs 0.1-0.2 mm||> 3|
|2||Resinous glands on fruits absent; overall pubescence consisting of white, capitate hairs 0.1-0.4 mm||> 4|
|3||Glands at apex of mature fruits; ribs not extending past glands; fruits oblong, base and apex truncate||Acleisanthes wrightii|
|3||Glands below apex of mature fruits; ribs extending past glands; fruits constricted at level of glands, oval-oblong, base tapering apex truncate||Acleisanthes acutifolia|
|4||Fruits 10-ribbed; leaves in each pair very unequal||Acleisanthes anisophylla|
|4||Fruits 5-ribbed; leaves in each pair slightly unequal||> 5|
|5||Ribs on fruit broad, flat, lacking grooves; leaf blades adaxially hirtellous on primary and secondary veins||Acleisanthes crassifolia|
|5||Ribs on fruit narrow, ridgelike, often with pair of parallel grooves between each rib or ridge; leaf blades uniformly puberulent to glabrate||> 6|
|6||Inflorescences usually solitary flowers, rarely geminate; chasmogamous flowers 7-17 cm||Acleisanthes longiflora|
|6||Inflorescences usually 2-5-flowered cymes, occasionally solitary flowers; chasmogamous flowers 2.5-5.5 cm||Acleisanthes obtusa|
|7||Perianths 4-15 mm, limbs pink or brownish orange; leaf blades from ovate or deltate to linear; at least young stems and leaves with minute, white, T-shaped hairs||> 8|
|7||Perianths 17-52 mm, limbs white, cream, or greenish yellow; leaf blades lanceolate, ovate, ovate-oblong, or ± diamond-shaped; at least young stems and leaves with minute, white, hairs not T shaped||> 9|
|8||Perianth limbs pink to lavender; perianth 4-6 mm; leaf blades ovate, ovate-oblong, or deltate; plants herbaceous; stamens usually 2||Acleisanthes chenopodioides|
|8||Perianth limbs brownish orange; perianth 10-15 mm; leaf blades linear or linear- lanceolate; plants woody at base or throughout; stamens 5.||Acleisanthes angustifolia|
|9||Pubescence of minute, flat, white hairs only; petioles 0-3 mm; leaf margins entire||Acleisanthes lanceolata|
|9||Pubescence of glandular hairs or multicellular conic hairs and minute, flat, white hairs; petioles 1-20 mm; leaf margins entire or undulate||> 10|
|10||Stems ascending to erect, sparsely leafy; leaves abruptly reduced toward inflo- rescence; fruits 8-10 mm||Acleisanthes parvifolia|
|10||Stems commonly decumbent, sometimes erect, densely leafy; leaves gradually reduced toward inflorescence; fruits 5-7 mm||> 11|
|11||Leaf blades ovate to ovate-oblong, leaves commonly drying brownish green; perianth limbs 15 mm wide||Acleisanthes diffusa|
|11||Leaf blades ovate to orbiculate, leaves commonly drying yellowish green; perianth limbs 10 mm wide||Acleisanthes nevadensis|