APOCYNACEAE  

Perennial herbs, with fusiform roots and usually a single, unbranched, slender stem. Leaves sessile, slender. Flowers in 2-more-flowered, subsessile or pedunculate, lateral or terminal umbels. Sepals 5, ovate or lanceolate, often acuminate. Corolla cream, with urceolate or campanulate tube, sometimes with decurrent ridges within, alternating with lobes, often bearded within mouth or with 5 small tufts of hairs in throat; lobes 5, oblong or ovate, sometimes hairy on face. Corona partly adnate to staminal column by lower, central part of face and as long as or longer than staminal column, of 5 lobes; lobes ovate, deltoid-ovate, oblong, rhomboid, or broadly cuneate, obtuse or acute, entire or 3-toothed with lateral teeth small and central tooth large or prolonged into a subulate or filiform, erect or incurved point. Anthers 2-locular, with membranous, apical appendage. Pollinia erect, terete, linear or oblong, sometimes curved, often pellucid on one margin; caudicles shorter than pollinia. Follicles slender, smooth, tapering into beak. Seeds with tuft of hairs.

Perennial herbs with flowering shoots produced annually from a tuber and dying back each year; all parts exuding a milky latex. Stems erect, simple or sparsely branched, with opposite and decussate lines of indumentum throughout. Leaves simple, entire, opposite and decussate or less often verticillate or irregularly inserted; petiole short; leaf base often sagittate, apex acute or obtuse, margin usually revolute; upper leaf surface usually with an indumentum of appressed scabrid hairs; lower leaf surface with pilose midrib, lamina +/- glabrous except for sparsely pilose lateral nerves. Inflorescences extra-axillary umbels, always pedunculate (except in S. bidens subsp. pachyglossum), several to many per stem, few- to many-flowered; bracteoles filiform, inconspicuous; inflorescence axes pilose. Calyx shorter than corolla; segments triangular, dorsally appressed-pilose, ventrally glabrous, with ciliate margin. Corolla contorted in bud, with lobes overlapping to the left; lobes elliptic, either flat or slightly cucullate or replicate, with variable indumentum; when margin ciliate, hairs present on both right- and left-hand margins. Corona lobes alternating with petals, each representing a dorsal outgrowth from opposing stamen; form of corona variable, lobes dorsiventrally flattened and often with 1 or 2 appendages on ventral face. Stamens united at base to form a hollow column from which corona lobes arise; each anther comprising a central area of 2 thecae, each containing one pollinium, an apical membranous appendage lying against or cupped over gynostegium, and two horny lateral margins; margins of adjacent anthers closely opposed, forming a narrow gynostegial groove between them, blocked at its upper end by a corpuscle. Pollinia pendulous, obtriangular, ellipsoid, reniform or sausage-shaped, dorsiventrally compressed, always with a germination zone present on circumference but never at point of attachment to caudicle; caudicles short, slender or somewhat flattened; corpuscle sometimes flanged. Ovary of 2 free carpels concealed within staminal column; styles tapering upwards, then uniting and broadening into a flat or umbonate style head. Follicles covered with long, soft appressed bristles, surface of carpel and bristles densely crispate-pubescent; fruiting peduncle elongating and pedicels becoming once-coiled at apex. Seeds many, compressed-ovoid with dark brown rugose testa and apical tuft of hairs of fine white hairs.

Perennials, herbaceous or becoming somewhat woody, twining or with several suberect branches from rootstock with long fleshy roots. Leaves mostly cordate at base. Flowers in laxly branched cymes or in fascicles at 2 or 3 nodes of flowering axis. Sepals usually with scales within base. Corolla with +/- inflated tube; lobes +/- as long as tube, usually connate at tips. Corona (1)2- or 3-seriate, arising from and +/- as long as staminal column; outer corona a shallowly 5-lobed, basin-shaped structure or a 5-lobed collar, with lobes shortly or deeply divided; inner corona lobes linear or subulate or shortly linear-oblong, incurved over anthers, rarely obsolete. Anthers 2-locular, tipped with a short, fleshy appendage or apiculus. Pollinia subglobose or ellipsoid; caudicles short. Follicles terete or fusiform, acuminate, +/- beaded, smooth. Seeds linear or oblong, convex on one side, flat on other, winged, with tuft of hairs at apex.

Trees or shrubs, usually glabrous. Leaves opposite or whorled, often large, shortly petioled, penninerved; axillary glands many in a dense fringe or in clusters; stipules 0. Inflorescence a terminal or pseudoaxillary, peduncled, usually many-flowered, simple or compound umbel or corymb, rarely a raceme. Flowers small, white or yellowish. Calyx small, divided almost to base or united into a shallow, 5-toothed cup, eglandular within; sepals or segments imbricate. Corolla salver-shaped; tube cylindric, slightly widened below mouth, very rarely just below middle; mouth constricted, without appendages; lobes shorter than tube, overlapping to the left. Stamens in widened part of tube; filaments short, terete; anthers 4-locular, free from stigma, ovate, acute to obtuse, shortly 2-lobed at base. Disc annular or cup-shaped, entire or slightly lobed. Ovary of 2 free or coherent carpels; style subterete; stigma capitate or shortly cylindric, minutely papillose and slightly viscous, with a basal, deflexed rim and a very short, slightly bilobed apiculus arising from a shallow depression; ovules 2 in each locule, collateral. Mericarps 2 (or often 1 by abortion) free, or +/- united, drupaceous; pyrenes crustaceous, 1- or 2-seeded, +/- compressed. Seeds ovoid. x = 11 (aneuploids, high polyploidy).

Succulent, sometimes spiky subshrubs or shrubs, branching at or above base to form clumps. Stems 4(5 or 6)-angled, not stoloniferous, glabrous, leafless, grey to purplish, with angles rounded, bearing stout, convex tubercles each armed with a hardened, conical, horizontal to decurved, yellow-brown tooth, each tooth sometimes flanked by two denticles, tubercles from adjacent angles meeting in middle of stem with well-defined groove. Inflorescences 1-20 per stem, glabrous, mainly in upper part of stem. Flowers solitary or produced in fascicles arising from peduncular patches in groove in middle of stem formed by tubercles. Corolla variously expanding, depending on number of flowers in fascicle, frequently papillate and spiculate, rarely hairy within, 7-25 mm diam., mostly much smaller than diameter of stems; tube rarely absent, bowl-shaped to conical, up to 5 mm deep; lobes ovate-lanceolate to linear-acute, margins sometimes ciliate, sometimes conspicuously folded back, 3-15 mm long. Corona: outer lobes deeply bifid, to shallowly bifid or entire and entirely enclosing space between inner lobes to form cup around column, arising near base of inner lobes; inner lobes adpressed to backs of anthers for most of length of anthers, occasionally initially incumbent and then rising up in centre in a small column, mostly dorsally flattened. Anthers 2-locular, horizontal on top of style head, rectangular. Pollinia ellipsoidal, with pellucid margin along outer edge. Follicles terete-fusiform, erect, diverging at up to 90deg. Seeds flattened, brown, finely papillate on surface, with tuft of hairs. x = 11.