Leaf Architecture and Epidermal Characters of the Argentinean Species of Proteaceae

Abstract

We describe the leaf architecture (venation and cuticle) of the eight extant species of Argentinean Proteaceae and discuss the diagnostic value of the characters. Proteaceae leaves are characterized by several architectural features. The leaves are ovate to oblong‐lanceolate or elliptic, with coriaceous texture, and have normal‐marginal petiole; the apexes vary between acute and obtuse, while the bases are acute to decurrent. They have pinnate simple first‐category venation, lack agrophic veins, have well‐developed areoles, and have two‐or‐more‐branched freely ending ultimate veins. Furthermore, all species have brachyparacytic stomata restricted to the abaxial surface of the leaves and multicellular trichomes. Cuticle features that differ among the species are the presence or absence of glands and papillae, and stomata size in relation to epidermal cell size. Architectural and cuticular features are also useful for differentiating tribes, subtribes, genera, and species within the subfamily Grevilleoideae. A key for the identification of Argentinean Proteaceae based only on leaf and cuticle characters is presented.