| Leaves opposite, entire or rarely dentate: fls. shades of blue or purple to violet, white, rose to red and rarely yellow to orange, sessile to long-peduncled, axillary, solitary or fascicled or cymose paniculate; calyx deeply 5-cleft or 5-parted, segms. linear or lanceolate; corolla-tube straight incurved or abruptly inflexed, the limb spreading, the lobes ovate or rounded; stamens 4, didynamous: caps, oblong-linear or clavate. About 200 species, chiefly Trop. S. Amer., a few in N. Amer. and extra-Trop. S. Amer., some in Trop. and S. Afr., Temp. Asia and in Austral. | | Leaves opposite, entire or rarely dentate: fls. shades of blue or purple to violet, white, rose to red and rarely yellow to orange, sessile to long-peduncled, axillary, solitary or fascicled or cymose paniculate; calyx deeply 5-cleft or 5-parted, segms. linear or lanceolate; corolla-tube straight incurved or abruptly inflexed, the limb spreading, the lobes ovate or rounded; stamens 4, didynamous: caps, oblong-linear or clavate. About 200 species, chiefly Trop. S. Amer., a few in N. Amer. and extra-Trop. S. Amer., some in Trop. and S. Afr., Temp. Asia and in Austral. |
| + | R. solitaria, Veil., is offered in the European trade, but its identity is doubtful, as R. solitaria, Vell., has been referred by some to R. Schnaeriana, Lindau, by others to R. calvescens, Lindau.—R. varians, Vent., is Daedalacanthus nervosus. |