Microscopy and Histochemistry of Leaves and Stems of Baccharis Subgenus Coridifoliae (Asteraceae) Through LM and SEM-EDS

Abstract

This research reports for the first time the anatomical characteristics of all species belonging to Baccharis subgenus Coridifoliae (Asteraceae). The anatomy and micro-morphology of aerial vegetative organs of ten species: B. albilanosa, B. artemisioides, B. bicolor, B. coridifolia, B. erigeroides, B. napaea, B. ochracea, B. pluricapitulata, B. scabrifolia, and B. suberectifolia are investigated by light and scanning electron microscopy. The number of secretory ducts, crystal morphology, presence or absence of conical nonglandular trichomes, leaves cross-section shape, margin morphology, anticlinal epidermal cell walls shape, and cuticle structure were identified as characters with diagnostic value for species. Similarity cluster analysis allows the formation of three groups based on a percentage of similarity between 45 and 84%. Some species showed differential characteristics as the presence of up to four secretory ducts in the midrib in B. albilanosa; smooth cuticles onboth sides of the leaf epidermis in B. erigeroides; flat midrib shape on both sides of the leaves in B. napaea; and convex–flat midrib shape in B. suberectifolia. The remaining species can be differentiated by a set of anatomical features. Anatomical and histochemical characteristics of stems and leaves provided data to support species identification.