Leaf and twig anatomy of the Pterostemonaceae (Engl.) Small: ecological and systematic features

An anatomical investigation of the leaves and twigs of Pterostemonaceae (Engl.), a monogeneric family of two species, has been made. The following anatomical characters in the leaf are of particular interest: glandular hairs, hydathodes on the marginal dentations and secretory substances in the glands and palisade cells. Characters of interest in the twig xylem include: vessel lumina of very small tangential diameter and with simple perforation plates; fibriform vessels with scalariform plates having one to six bars and also plates with perforations in irregular patterns.