XVI International Botanical Congess

Considerable mystery surrounds the origins of high-elevation endemics found on Mount Kinabalu. This mountain is ca. 1.5 million years old yet is the highest mountain between the Himalayas and Irian Jaya. Several high-elevation endemic Dendrochilum species occur on Mount Kinabulu that provide an appropriate model system with which to study the origins of the mountain's flora. A set of phylogenetic tests were used to investigate hypotheses concerning 1. Biogeography and 2. Hybridization within Dendrochilum. First, hypotheses that the endemics arose from ancestors in other high mountains of southeast Asia (Sumatra or the Philippines) were rejected whereas an origin from lower elevation ancestors in Borneo was Accepted. Second, a origin by hybridization for D. acuiferum was inferred with the most likely parents D. grandiflorum and D. stachyodes. It is concluded that the origins for many endemics on Mount Kinabalu is both recent and local with hybridization an important process generating diversity on the mountain.