Stems 4-angled,1.5-2 cm thick. Corolla wheel-shaped, 8-22 cm wide, purple, lobes acute-oblong, acute-elliptic or long-pointed-ovate, much longer than tube.

S Africa

 

S. leendertziae N.E. Br. from S Africa has stems 4-angled, about 1.5-2 cm thick. Corolla deeply bell-shaped, 3-4 cm wide, purple, lobes long-pointed, d-shaped, and much shorter than tube.

Source: Forster, P.; Liddle, D.; Liddle, I. (2002). Hoya. In: Spencer, R.. 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.