Climbing or scrambling perennial vine. Leaves alternate, sometimes with 5 lobes and long petioles. Calyx bell-shaped, rose to lilac. Corolla reddish to dark maroon to blackish, to about 6 cm long, 5-lobed at the tip. Stamens 4. [R. volubile Otto & Dietr.]

Mexico

Source: Spencer, R. (2002). Scrophulariaceae. 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.