Observations of gynoecial structure in Philodendron (Araceae)

MAYO, S. J., 1989. Observations of gynoecial structure in Philodendron (Araceae). The gynoecial morphology and anatomy of 15 species of the genus Philodendron , representing all the subgenera and a majority of the sections, are described and illustrated. The study emphasizes the morphology of the style, compitum and stylar canals; gynoecial vasculature is only superficially treated. Variation of gynoecial morphology in P . subgenus Meconostigma is described and illustrated and a pilot study of gynoecial ontogeny in this subgenus is presented. Ideas on phylogenetic trends in style and stylar canal morphology, ovary locule number, placentation and ovule number are discussed. Gynoecial characters are shown to be taxonomically useful at the subgeneric and sectional level in Philodendron. The following taxonomic and nomenclatural changes are made: P. section Pteromischum is raised to subgeneric rank. In P. subgenus Philodendron sections Polyspermium and Oligospermium are reduced to the synonymy of sections Philodendron and Calostigma respectively, and the following new names and combinations are made at subsectional rank: subsections Canniphyllum, Oligocarpidium, Bulaoanum and Eucardium.