Apocynaceae  

 ♦ Apocynaceae    (Takhtajan, 2009)

Plant with a well-developed latex-system (except in Nerium), and commonly producing cardiotonic glycosides. Steroidal alkaloids, cardenolides, group II decarboxylated iridoids present. Trees, shrubs, herbs, very often lianas, sometimes succulents, glabrous or with various kinds of trichomes. Stem often of anomalous structure. Vessels with scalariform or simple perforations; Leaves opposite or sometimes verticillate, rarely alternate, simple, entire or rarely lobed or dentate; stipules wanting or rarely small and interpetiolar or vestigial. Flowers in cymose or racemose inflorescences, or solitary, bisexual or very rarely functionally unisexual, actinomorphic or nearly so, commonly 5-merous.Sepals (4)5, more or less connate, imbricate or valvate. Corolla sympetalous, lobes contorted or rarely imbricate or valvate. Stamens as many as and alternate with the corolla lobes, inserted on the corolla tube, free or more often connate; filaments short; anthers free or more or less closely coherent or connate around the style head, basifixed or dorsifixed, tetra sporangiate, bisporangiate or disporangiate, introrse, opening longitudinally or apically. Pollen grains 3-celled, in monads, tetrads or pollinia, 3-colporate or porate. Nectar secreted in alternistaminal troughs on staminal tube or staminal feet or from disclike nectary around base of ovary, more rarely from sides of ovary or absent. Gynoecium of 2(-8) carpels, these connate in varying degrees; ovary superior to semiinferior, stigma mostly on underside of style head, often restricted to five chambers behind guide rails. Ovules two to many, commonly pendulous, anatropous, amphitropous , or hemitropous. Fruits of diverse types . Seeds small, exotestal, often with a terminal coma of long hairs, naked, winged or arillate , with straight embryo and oily, copious to scanty endosperm. n = 8–12 A.L. de Jussieu 1789 (including Asclepiadaceae Borkhausen 1797, Cerberaceae Martynov 1820, Cryptostegiaceae  Schlechter 1905, Cynanchaceae G. Meyer 1836, Ophioxylaceae Perleb 1838, Periplocaceae Schlechter 1905, Plumeriaceae Horaninow 1834, Stapeliaceae Horaninow1834, Vincaceae Vest 1818, Willughbeiaceae J.G. Agardh 1858). 432/5100. Classification after M.E. Endress and P.V. Bruyns (2000) and M.E. Endress and W.D. Stevens (2001).

11.1 RAUVOLFIOIDEAE
Anthers not adherent to style head by a reticulum of viscid exudates, full of pollen, rarely with spines. Fruits dehiscent or indehiscent, berries, drupes, follicles, or capsules. Seeds naked, with wings or arils, but almost never with coma at one end; holmindole alkaloids present or absent, n = 9 (Alyxieae), 10, 11, (23). – alstonieae: Microplumeria, Tonduzi ; vinceae: Vinca, Catharanthus; wullughbeieae: Paucouria,; tabernaemontaneae: Tabernanthe; melodineae: Stephanostegia; hunterieae: Hunteria, Pleiocarpa; plumerieae: Thevetia, Plumeria; Carisseae: Carissa, Acokanthera; alyxieae: Alyxia.

11.2 APOCYNOIDEAE

Corolla left-contorted, valvate. Anthers tetrasporangiate, adherent to style head by a retinaculum of viscoid exudates, empty at base and with spines. Nectaries, if present, in ring around base of ovary. Seeds ecomose or comose, n = (6-) 10, 11 (12).  wrightieae: Nerium, Adenium; malouetieae: Malouetia; apocyneae: Apocynum; mesechiteae: Mandevilla; echiteae: Prestonia, Echites.

11.3 PERIPLOCOIDEAE

Corolla valvate, tube formation intermediate. Filaments free from each other. Anthers tetrasporangiate. Two pollinia (consisting of loosely coherent tetrads) in each locule, transferred by spoon-shaped translator ending in a sticky disc, n = 11 (mostly). Periploca.

11.4 SECAMONOIDEAE

Corolla left-contorted. Filaments connate. Anthers tetrasporangiate. Two very small pollinia in apical part of each locule, transferred by translator with arm that has two clefts. – Secamone,.

11.5 ASCLEPIADOIDEAE

Filaments connate. Anthers bisporangiate, with onesolid pollinium in each locule (pollen in tetrads –Fockeae), transferred by translator, orbicules presentor (Riocreuxia) absent, granular layer of exine thin; n = 9–14. – fockeeae: Fockea: marsdenieae: Gymnema , Spirella, CEROPEGIEAE: Leptadenia, Brachystelma, Ceropegia, Macropetalum, Caralluma, Stapella, Huernia, Duvalia, Rhytidocaulon; asclepiadeae:  Sarcostemma, Cynanchum, Calotropis, Lachnostoma, Pergularia, Asclepias, Gomphocarpus, Kanahia, Pentastelma , Pentatropis, Glossonema, Odontanthera, Solenostemma, Blyttia, Diplostigma. Here we follow Endress and Stevins (2001) in combining Apocynaceae and Asclepiadaceae into one family. Cronquist (1981: 861) states “There is a fairly straight-line evolutionary series in floral morphology within the Apocynaceae and Asclepiadaceae collectively, from the Plumerioideae to the Apocynoideae to the Periplocoideae to the Secamoneae and thence to the other tribes of the Asclepiadoideae.”Closely related to the Strychnaceae, Gentianaceae and Geniostomaceae clade (see Struwe et al. 1995).