NEW-WORLD PODOSTEMACEAE - ECOLOGICAL AND EVOLUTIONARY ENIGMAS

The largely tropical Podostemaceae occur in a unique habitat for angio sperms: attached to rocks in river rapids and waterfalls. Little taxon omic work has been published on New World Podostemaceae since Van Roye n's monograph in the early 1950s. A paucity of complete herbarium mate rial severely limits taxonomic study and precludes addressing a range of enigmatic ecological and evolutionary issues that relate to the fam ily. The size, high level of endemism, and life history of the family are discussed. The distributions of two species in Mexico are used to illustrate the need for concerted collecting efforts. Recommendations for collection strategies are made that reflect the unusual habitat an d life history of these plants.