Abstract

A survey was carried out in Mount Cameroon to document the distribution and diversity of the Orchidaceae which is the most abundant plant family worldwide and the second most abundant in this study area. The study area was divided into 5 different zones made up of 4 ecotypes in the wild and some cultivated gardens. The ecotypes in the wild were further divided into different macro-habitats based on altitudinal gradients and the sides of the mountain (leeward and windward). A total of 11 macro-habitats were surveyed and an inventory of all species present was made, samples were collected and identified using morphological techniques. Their identities were confirmed using molecular techniques and phylogenetic analyses established.  A total of 4,528 orchids belonging to 86 species and 26 genera were observed. The most abundant genus (25 species) was Bulbophyllum, with Habenaria procera (1,155 individuals) being the most abundant species. The macro-habitat with the least number of individuals (855 individuals) was the montane rainforest, while the lava outcrop had the highest number of individuals (3,238).  The windward side had 2,673 individuals, the leeward side had 1,559 individuals and the cultivated gardens had 296 individuals. Based on molecular phylogeny, the orchids were grouped into three subfamilies; the Orchidiodeae, and Vanilloideae with one species each, while the Epidendroideae had 84 species. Bulbophyllum dayanum and Bulbophyllum bequartii were recorded for the first time in the Mount Cameroon. A single stand of Ansellia africana which is considered as being vulnerable by IUCN 2010 occurred only in the 1995 lava flow. The diversity and distribution of orchids in Mount Cameroon is high, but there is need for conservation through domestication.

Key words: Diversity, Mount Cameroon, orchids, Bulbophyllum.