Abstract

FOROUGHBAKHCH, R et al. Quantitative measures of leaf epidermal cells as a taxonomic and phylogenetic tool for the identification of Stanhopea species (Orchidaceae). Phyton (B. Aires) [online]. 2008, vol.77, pp.113-127. ISSN 1851-5657.

Orchids of the genus Stanhopea are currently identified only by their floral structure characteristics. A statistical analysis of a significant number of species of this genus disclosed that measurements of adaxial and abaxial epidermal cell surface areas can be correlated with specific recognized species by a leaf printing method. This allows an objectively either positive or nearly positive confirmation of the identity of a species in the absence of flowers and without damage to plants. When ordering the mean values obtained for these surface areas in each species in a decreasing order, a correlation was observed in a hierarchical way that went from primitive to more advanced floral forms. This reflects the evolutionary radiation of the genus. It is established that in Stanhopea, the presence of large leaf epidermal cells on species from South America represents a primitive evolutionary condition that became to smaller cells in evolutionarily more recent individuals as the genus radiated towards Mexico.

Keywords : Stanhopea; Quantitative taxonomy; Morphometry; Leaf printing; Orchidaceae.

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