9306891 Croat Field collecting of plants in native habitats followed by intensive laboratory and herbarium study remain the most efficient means of identifying and classifying the rich plant life of the tropics. Dr. Thomas Croat of the Missouri Botanical Garden, a specialist on the aroid or philodendron family, is studying the neotropical genus Dieffenbachia in Mexico and Central America, with an estimated 30-35 species, in preparation for a taxonomic monograph of the group. The genus includes the second most important species of ornamental plant in terms of commercial sales in the U.S.; however, relationships among species, sources of germplasm for breeding, geographical ranges, and aspects of pollination and dispersal biology and possible hybridization are poorly known. Descriptive information about the plants, taken from living material and herbarium specimens, is entered in a computer database, which eventually will be accessible over the Internet to interested researchers and students. The research will lead to improved diagnosis of each species, a preliminary account of phylogenetic relationships, mapping of geographic ranges, notes on flowering and fruiting phenology and other aspects of ecology, and identification keys for reliable assignment of scientific names. The inventory of plant diversity in the tropics remains an ongoing endeavor by a small group of devoted taxonomic specialists. The collections they create, both herbarium specimens and living material in botanical gardens, and the published information and, now, computerized records, become resources for wise use and stewardship.
