Leaf anatomy as subsidy to the taxonomy of wild Manihot species in Quinquelobae section (Euphorbiaceae)

Abstract

This work aims to characterize the anatomy of leaves of wild Manihot species (Euphorbiaceae) and identify anatomical characteristics of taxonomic importance. Samples of M. violacea var. cecropiaefolia, M. violacea var. divergens, M. violacea ssp. jacobinensis (Lencois) and M. violacea were collected in cerrado (savanna), and samples of M. violacea ssp. jacobinensis and M. violacea ssp. jacobinensis (Mucuge) were collected in campo rupestre (rocky land) areas in northeastern Brazil. The leaf anatomy of these species was analyzed using optical and scanning electron microscopy in order to obtain useful characters for the taxonomy of the genus. Information acquired confirms the records from the literature for the genus. The taxonomic characters that were considered to be the most important are as follows: number of vascular bundles and petiole outline; distribution of secretory idioblasts; and presence of papillae and midrib outline. All of these species have secretory idioblasts, crystals, laticifers and isobilateral mesophyll. Most of the species present a cylindrical petiole outline. The number of vascular bundles on the petiole varies between five and ten. The similarity analysis reinforces M. jacobinensis as a distinct species.