Leaf morphology and anatomy of Richterago discoidea (Asteraceae): a taxonomic and ecological approach

Abstract

Richterago discoidea (Less.) Kuntze (Asteraceae) has the largest distribution among the species of this genus in the Espinhaço Range. This species has wide morphological variations, which reflects its complex taxonomic history. This study aims to describe morpho‐anatomical leaf characters and recognizes potential biological factors that contribute to species diversity. The collected material is deposited in the ALCB, CEN and HUEFS Herbaria. For the analysis of the leaf anatomy, leaves of five individuals per municipality were collected, except for Brasília, where only three individuals were collected. Cross sections in the middle of the leaf blade, at the base and at the petiolus / sheath were carried out using a rotary microtome. Statistical tests were conducted to test environmental responses. The results revealed that it is not possible to associate morphological patterns to habit, leaf characters, substrate type and geographical distribution, since there were different combinations in the same population. Regarding anatomical data, cuticle thickness, epidermal cell wall thickness and contour (sinuous or straight), presence of hypodermis and stomatal index varied within and between populations. The characters evaluated do not characterize any taxonomic complex for the species, and leaf anatomical variation can be reported as a response to environmental conditions.