A Tuberous and Epiphytic New Species of Impatiens (Balsaminaceae) from Southwest Cameroon

Abstract

Grey-Wilson (1980) recorded 110 species of Impatiens for Africa (excluding Madagascar), of which he considered only six to be wholly epiphytic: I. keilii Gilg, . paucidentata De Wild., I. glandulisepsala Grey-Wilson, I. iteberoensis R.Wilczek & G. M. Schulze, I. letouzeyi Grey-Wilson and I. grandisepala Grey-Wilson. Fischer (1997) added a further obligate epiphyte, I. irangiensis Eb. Fisch. from eastern Congo. However, none of these are recorded as being tuberous. Some terrestrial grassland species of Impatiens in East Africa are known to have perennating underground tubers, but these are slender and not spherical or ellipsoidal as in the species described here. In Madagascar, at least three species bear spherical to ellipsoidal tubers, the most spectacular of these, with tubers 20 cm diameter or more, being Impatiens tuberosa H. Perrier, which grows on rocks in northern Madagascar. The species described in this paper is wholly epiphytic, growing in tree crowns (or just below them). It is particularly common on stunted trees growing on ridges near the peak of Mt Etinde. The brightly coloured red and yellow flowers suggest that L etindensis is pollinated by birds. Despite searches elsewhere on the mountain, this species has been recorded nowhere else apart from a single collection just to the west of Etinde, on the slopes of Mt Cameroon proper, above the village of Njonji. Although sterile, this specimen is recognisable as L etindensis by the presence of the distinctive tubers. Mt Cameroon is one of the best botanized localities in