Stem and leaf morphoanatomy of two Atlantic Forest species of Smilax Linnaeus

Abstract

In this work, we analyze the morphoanatomical characteristics of the stem and leaves of Smilax quinquenervia and Smilax subsessiliflora in order to detect aspects that can help identify these species. Specimens were collected in the municipality of Miguel Pereira, Rio de Janeiro, Brazil, and histological slides were prepared according to traditional techniques of plant anatomy. Some anatomic characteristics are common to both species, including raphide and prismatic crystals of calcium oxalate and the occurrence of a sclerenchymatic sheath in the vascular bundles. Other aspects have diagnostic value for the species analyzed: thorns (vascularized emergences) at the nodes, striated cuticle, and cortical vascular bundles appearing as leaf traces in the aerial stem of S. quinquenervia; cork warts in the leaf and groups of palisade cells in the mesophyll of S. quinquenervia; aculei (non-vascularized emergences) at the nodes and internodes, striated cuticle with micropapillae, and a biseriate epidermis in the aerial stem of S. subsessiliflora; presence of groups of lobate cells in the mesophyll of S. subsessiliflora. A comparative table, which points to these aspects and others referenced in the literature for the Smilax species, is provided. The anatomical studies of the two species analyzed provide the basis for their recognition.