Origins and ecology of the tropicalpine flora of Mt Wilhelm, New Guinea

Floristic elements within the tropicalpine flora of Mt Wilhelm are defined on taxonomic and distributional criteria, and are compared ecologically. The hypothesis that elements of apparently most recent immigration would retain to the largest degree characteristics appropriate to colonists of insular locations and to plants of temperate zone environments is confirmed. Good colonizing ability, rapid growth rate, continuous flowering and growth in the field, successful flowering in cultivation, vulnerability to frost, lack of preference for slopes of particular aspect, and wide and generally low altitudinal range were all present to a greater extent in more recently immigrant floristic elements. Dispersal ability was not significantly correlated with floristic elements. It is concluded that the tropicalpine flora is a youthful one consisting largely of the descendants of immigrant herbs which arrived by dispersal over long distances in Plio-Pleistocene times. A few forest plants of ancient status in New Guinea have become adapated to the tropicalpine environment, and several established aliens provide indications of migration ability lost to varying extents by elements within the native flora.