Anatomical aspects of the taxonomy of sedges (Carex, Cyperaceae)

Abstract

Patterns of variation in the anatomy of achene epidermis and leaves were examined to assess the utility of anatomical characters in systematic and phylogenetic studies of Carex and the Cyperaceae. This study was based primarily on a review of the available literature. In addition, foliar anatomy of species in Carex sect. Phacocystis was investigated and patterns of variation within the section were analyzed using a centroid cluster algorithm. Nearly all genera and all sections of Carex for which data are available include species with single conical silica bodies in the achene epidermal cells as well as species with more elaborate, presumably derived, silica bodies. Similarly, most sections within Carex include species that have hypostomatous leaves with a single layer of bulliform cells and that lack papillae, as well as species with amphistomatous leaves, papillose epidermal cells, or multiple bulliform cells. Application of the "common equals primitive" in group criterion for determining evolutionary polarity indicates that single conical silica bodies and epapillose hypostomatous leaves are primitive character states in Carex. As both primitive and derived character states are widely distributed among sections, anatomical characters should not be generally applied as measures of similarity in phenetic approaches to classification but have potentially major importance in phylogenetic studies within and among sections.