Value of the foliar micromorphology in the sectional classification of South American Hybanthus species (Violaceae).

SEO, M. N., SANSO A. M. & C. C. XIFREDA

Feira de Santana. Brasil

Congreso; 60º Congresso Nacional de Botânica de Brasil; 2009

Sociedade Botanica do Brasil

Hybanthus Jacq. Subg. Ionidium (Vent.) Schulze-Menz is represented by nearly 45 species in South America. Schulze-Menz (1936) subdivided it in four sections; later on, Sparre (1950) recognized only two of the Schulze-Menz´groups and suggested the circumscription of three new ones, by splitting the sections and regrouping of species. The complexity of both previous infragenerical treatments was related with the lack of  diagnostic macromorphological characters. The objective of our study was to investigate leaf micromorphological characters in order to re-evaluate previous morphological classifications and to appreciate their taxonomic value in the delimitation of Hybanthus sections. A micromorphological study of leaf surfaces and margins of 25 representative species was performed with Scanning Electronic Microscopy (SEM). The material was obtained from wild populations and/or herbarium specimens. At least, five leaves of each species were analyzed. The studied species were assigned to five different SEM types, I to V. These morphological patterns were established in accordance with the presence or absence of different kind of trichomes and papillaes on the leaf surface and margins. The results support previous opinions of taxonomic specialists in relation to maintain the sections Hybanthus Subg. Ionidium Sect. Bigibbosae Schulze-Menz and Sect. Micranthae Schulze-Menz. Three sectional names are proposed: Hybanthus Sect. Ionidium is automatically established and Sections Parviflorae and Pombalia are here designated. Hybanthus atropurpureus is designated lectotype for Hybanthus Sect. Micranthae. A diagnostical key for identification as well as descriptions of the sections are proved.