The mimosa group of tropical legumes are woody plants that range in stature from small prickly shrubs of Mexican and Argentine deserts or Caribbean coral reef-shores to gigantic emergent forest trees of Brazilian Amazonia. They enter all woodland shrub communities of the Neotropics below about 2000 meters elevation, and are an almost ubiquitous element in the flora of forest margins. Numbered among them are the stately saman (Albizia saman), which fills in urban Latin America the role of the banyan in India, and in rural Latin America provides shade and a crop of nutritious fruits for cattle; and the guamuchil (Pithecellobium dulce), a staple of rural markets, the seeds of which are enveloped in sweet pulp esteemed as a fruit and as basis for summer drinks. Most of them, however, are appreciated primarily by local people, for whom they provide nursery shade trees in the coffee orchards, timber used in construction, furniture, and as fuel, and are a rich source of honey. In these roles the mimosas of the Americas have acquired a large vocabulary of vernacular names, both in Amerindian and Latin languages, testifying to their importance in the lives of the people who use them. The last comprehensive taxonomic inventory of the mimosa group dates back to 1875. Since then much has been learned about them, and many new species have been discovered and described. Most of these exist, so far as retrievable information goes, only as names in obscure technical publications, and no one can say for sure how many are truly distinct species, or where they are to be found, or how they should be named according to current rules of botanical nomenclature. There is no modern inventory other than the patchwork of accounts that have appeared in floras of political units, many of which are mutually contradictory, one species appearing under different names in different countries, and several distinct species often masquerading under one name. Without a reliable inventory, no rational decisions can be made about the management, exploitation, or conservation of woody floras on which the function of ecological systems and the prosperity of mankind depend. Drs. Rupert Barneby and James Grimes of the New York Botanical Garden are providing this modern inventory, for the woody tropical legumes of the large genus Pithecellobium and its relatives. The results will serve as a source of verified information on which the writers and users of floras can depend, for practical identification of species, for correct scientific nomenclature, for indication of geographical ranges and habitat occurrences, and for documentation of economic uses by local peoples.
