Common Name: DOGBANE FAMILY
Habit: Annual, perennial herb, shrub, tree, often vine; sap generally milky. Leaf: simple, alternate, opposite, subwhorled to whorled, entire; stipules 0 or small, finger-like. Inflorescence: axillary or terminal, cyme, generally umbel- or raceme-like, or flowers 1--2. Flower: bisexual, radial; perianth parts, especially petals, overlapped, twisted to right or left, at least in bud; sepals generally 5, fused at base, often reflexed, persistent; petals generally 5, fused in basal +- 1/2; stamens generally 5, attached to corolla tube or throat, alternate lobes, free or fused to form filament column and anther head, filament column then generally with 5 free or fused, +- elaborate appendages abaxially, pollen +- free or removed in pairs of pollinia; nectaries 0 or near ovaries, then 2 or 5, or in stigmatic chambers; ovaries 2, superior or +- so, free [fused]; style tips, stigmas generally fused into massive pistil head. Fruit: 1--2 follicles, (capsule), [berry, drupe]. Seed: many, often with tuft of hairs at 1 or both ends.
Genera In Family: 200--450 genera, 3000--5000 species: all continents, especially tropics, subtropical South America, southern Africa; many ornamental (including Asclepias, Hoya, Nerium, Plumeria, Stapelia); cardiac glycosides, produced by some members formerly treated in Asclepiadaceae, used as arrow poisons, in medicine to control heart function, and by various insects for defense. Note: Asclepiadaceae ("asclepiads"), although monophyletic, included in Apocynaceae because otherwise the latter is paraphyletic. Complexity of floral structure, variation in asclepiads arguably greatest among all angiosperms. Pattern of carpel fusion (carpels free in ovule-bearing region, fused above), present +- throughout Apocynaceae (in broad sense), nearly unknown in other angiosperms. Base chromosome number generally 11; abundance of latex, generally small size of chromosomes evidently have impeded cytological investigations.
eFlora Treatment Author: Thomas J. Rosatti, except as noted
Scientific Editor: Bruce G. Baldwin.
Habit: Perennial herb [shrub]. Stem: generally twining or trailing. Leaf: opposite, generally +- persistent; blade thread-like to narrow-lanceolate. Inflorescence: at nodes, umbel-[raceme-]like cyme. Flower: corolla lobes +- spreading to erect-incurved, ring of tissue at corolla base present or not; filament column appendages +- 0 or free from each other, fused to ring of tissue at corolla base or not, +- spheric, attached to base of filament column, without projections, hollow (possibly due to complete fusion of margins), anthers fused into anther head around and fused to pistil head, pollen in pollinia; pistil head flat or, if +- conic, 2-lobed or not; nectaries in stigmatic chambers. Fruit: generally 1, erect or pendent, narrow-fusiform to lance-ovoid, with fine longitudinal grooves [or smooth]. Chromosomes: 2n=20,22,40,44 (reports not including California plants).
Species In Genus: +- 40 species: North America, Africa to Australia. Etymology: (Greek: fleshy crown or wreath, from sac-like filament column appendages of some species) Note: Our species treated as Cynanchum, Sarcostemma in TJM (1993), both shown to be polyphyletic in previous, broader circumscriptions (Liede & Täuber 2000, 2002).