Content area
Abstract
The flowering plant family Samydaceae was recently reinstated to include 14 genera and about 256 species of tropical trees and shrubs. Preliminary analyses of relationships in the family, however, indicated that the largest genus in the family, Casearia, is not monophyletic and that several smaller groups are probably misplaced. In order to affirm or refute those hypotheses, additional DNA sequence data with broader taxon sampling from the Old World were gathered for phylogenetic analysis. Phylogenetic inferences were drawn from parsimony, likelihood, and Bayesian analyses of plastid and nuclear DNA data. The results affirm the monophyly of Samydaceae and consistently recover four major clades, which are here circumscribed as four tribes. The results also affirm that Casearia is not monophyletic. Rather, several small genera (Samyda, Laetia sensu stricto, Hecatostemon, and Zuelania) are nested within it. One previously recognized genus, Piparea, which is more closely related to Ryania and Trichostephanus, should be reinstated. Nomenclatural changes are presented here to bring generic circumscriptions in line with phylogenetic relationships within Samydaceae and with the proposed conservation of the name Casearia over Samyda and Laetia. A taxonomic revision of Casearia in south-central Asia, including the area from Pakistan to Burma and south from the Himalayas to Sri Lanka, is also presented. Thirteen species are recognized, nine of which are endemic to south-central Asia and four of which are more widespread, also occurring eastward into China, southeast Asia, and Malesia. Descriptions, taxonomic keys, and distributional maps are provided for the species.
