SYSTEMATIC WOOD ANATOMY OF THE GENUS TAPIRIRA AUBLET (ANACARDIACEAE) - A NUMERICAL APPROACH

A wood anatomical study of the Mexican species of Tapirira was underta ken to uncover evidence to help clarify the systematics of the genus. Three to five individuals of each of 10 populations from throughout th e range of the genus in Mexico were studied. For comparative purposes, three Central and South American species were also examined. Cluster analysis showed that the genus in Mexico can be separated into two phe netic units, represented by T. mexicana, a species widely distributed in Mexico, and T. chimalapana, a species endemic to the Isthmus of Teh uantepec. Canonical discriminant and factor analyses indicate that the quantitative wood characters most useful in distinguishing these spec ies are wall thickness of fibers and vessels, diameter of fiber lumen, and diameter and frequency of radial canals. These species also diffe r in presence/absence of tannins in the fibers and color and specific gravity of the wood. The South American species, Tapirira bethanniana, T. guianensis, and T. obtusa, have wood anatomy similar to that of T. chimalapana. The differences in the wood anatomical characters betwee n T. mexicana and the other taxa suggest that the infrageneric classif ication of Tapirira should be reevaluated. The results of this study s upport the utility of sampling of populations in comparative wood anat omy.