Decorsella arborea, a second species in Decorsella (Violaceae), and Decorsella versus Rinorea

Abstract

A new species of Violaceae, Decorsella arborea Jongkind, is described and illustrated. The new species differs from the only other species in the genus, D. paradoxa A. Chev., by the larger size of the plants, smaller leaves, more slender flowers, and stamen filaments that are free for a much larger part. Both species are from the Guineo- Congolian forest of tropical Africa. The differences between Decorsella and Rinorea are discussed. Confirming recent reports, some species of Rinorea can have zygomorphic flowers and some of these can be almost equal in shape to Decorsella flowers.