Shrub or scandent climber to 10 m high, evergreen. Leaves 3-whorled; blade elliptic to oblanceolate, up to 10 cm long and 2.5 cm wide; upper surface glossy green, glabrous; lower surface pale green, glabrous; tip acute to rounded; base cuneate. Flowers 5.1-6.1 cm wide at mouth; corolla yellow to apricot, with red patch towards lobe base; lobes linear lanceolate,19-50 mm long. Fruit 10-18 cm long and 1-1.5 cm wide. [S. capensis A. DC.]
S Africa, Zimbabwe
S. amboensis (Schinz) Engl. & Pax from Namibia and Zaire is a shrub or scandent climber to 20 m high, deciduous. Leaves opposite; blade broadly ovate to ovate, up to 12.5 cm long and 6.5 cm wide; upper surface glossy green, glabrous; lower surface pale green, glabrous; tip acute to long-pointed; base cuneate to rounded. Flowers 0.6-1.3 cm wide at mouth; corolla red-violet, lobes linear-lanceolate, 25-75 mm long. Fruit 12-27 cm long, 1.5-2.5 cm wide.
S. divaricatus (Lour.) Hook. & Arn. from China and Vietnam is a shrub or scandent climber to 4.5 m high, evergreen. Leaves opposite (rarely 3-whorled); blade elliptic to obovate, up to 9 cm long and 4 cm wide; upper surface dark green, glabrous; lower surface pale green, glabrous; tip acute to long-pointed; base cuneate. Flowers 0.5-1.2 cm wide at mouth; corolla white-yellow, with red spots, lobes linear-lanceolate, 35-100 mm long. Fruit 9-15 cm long, 1.7-3 cm wide.
S. gratus (Wall. & Hook.) Baill. from Africa is an evergreen scandent climber to 20 m high. Leaves opposite; blade elliptic, ovate or obovate, up to 18 cm long and 9 cm wide; upper surface dark glossy green, glabrous; lower surface pale green, glabrous; tip long-pointed; base cuneate to rounded. Flowers 1.3-2.2 cm wide at mouth; corolla white to yellow, becoming red-purple near mouth, lobes orbicular, 14-35 mm long. Fruit 23-41 cm long, 3-4.3 cm wide. [Roupellia grata Wall. & Hook.]
Source: (2002). Apocynaceae. In: . Horticultural Flora of South-eastern Australia. Volume 4. Flowering plants. Dicotyledons. Part 3. The identification of garden and cultivated plants. University of New South Wales Press.