Atlas of Foliar Surface Features in Woody Plants, IV. Rhododendrons (Ericaceae) of Eastern North America

Abstract

Scanning electron microscopy was used to examine the surfaces of leaves of representatives 6 native evergreen rhododendrons [Rhododendron carolinianum, R. minus, R. chapmanii; R. lapponicum, R. catawbiense, R. maximum]. Seven trichome types are recognized, necessitating some terminology previously unused in the genus. Six vestiture types and 4 cuticular patterns are described. A ferruminate surface, formed by the degradation and conglutination of trichomes, is described for R. maximum. The trichome complements and cuticular patterns correlate well with the subgeneric classification and provide an aid in distinguishing the 2 spp. of elepidote rhododendrons, but do not show differences among the 3 taxa of the lepidote R. minus complex. Descriptions and illustrations are given for all species.