9310171 Croat and Zhu Graduate student Zhu under the supervision of Dr. Croat is undertaking a taxonomic study of tropical aroids of the genus Dracontium, of which there are an estimated 20 species in the New World tropics. Materials for study include preserved herbarium specimens borrowed from various national and international museums and supplemented with new field collections to be made in Costa Rica, Venezuela, and Ecuador with the help of host country colleagues. New features of morphology and anatomy including pollen and chromosomes are being analyzed, to acquire reliable characters for taxonomic discrimination and for construction of a stable classification of the species. Field observations on pollination will help understand the differences in floral form among the species. %%% Numerous groups of tropical plants are poorly known, often from single or few collections made decades ago by various natural history expeditions. This doctoral thesis project will focus on the New World species of a group of tuberous aroids related to philodendrons and anthuriums, and will result in greatly increased collections available for morphological and biochemical studies, as well as improved methods of species recognition, a more stable classification, and the first analysis of phylogenetic relationships among these species and with putatively related genera.
