PLANT: Erect or vining perennial herbs. LEAVES: opposite. FLOWERS: solitary, axillary, perfect; corolla funnelform; anthers not connivent. FRUIT: terete. SEEDS: naked. NOTES: 5 spp. native to Eur., n Afr., w Asia (abbreviated from Pliny's Vincapervinca). REFERENCES: McLaughlin, Steven, P. 1994. Apocynaceae. J. Ariz. - Nev. Acad. Sci. Volume 27, 164-168.
Fls perfect, hypogynous, sympetalous, regular or nearly so, mostly 5-merous; cor commonly funnelform or salverform to urceolate or cylindric, with mostly convolute lobes; stamens on the cor-tube, alternate with the lobes; anthers distinct or ±closely connivent around the style-head; ovaries 2 in our genera, with a common style and large stigma; ovules few to many; fr in ours of 2 slender, many-seeded follicles; ours herbs or twining woody vines with milky juice and opposite or (Amsonia) alternate, simple lvs. 200/2000, mostly tropical.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.