Adventiciuos species of Viola (Violaceae) from Argentina

SANSO, A. M., XIFREDA, C. C. & COLASANTE, M.

Vicosa, Brasil

Congreso; 55° Congresso Nacional de Botânica de Brazil; 2004

Sociedade Botanica do Brasil

The genus Viola L. is widely distributed on New and Old World, mostly in temperate regions, and comprises the commonly known “violets”. In Argentina, grow around forty-five species, mostly are native taxa and some ones have been introduced. All of these last species are of ornamental importance and some ones are used as medicinal. In this contribution nomenclatural and taxonomic aspects are revised. Materials deposited in Argentine and Italian herbaria were studied. The original descriptions and the nomenclature types were seen when it was possible; otherwise phototypes, drawings or digital images were observed. With the aim of contributing to a better characterization of these entities, micromorphology of the seeds was analyzed under SEM. Observations on foliar anatomy of the medicinal species were carried out transversal sections stained with methylene blue, previously fixed in glutaraldehyde and embedded in Spurr resine. We recognize four adventitious species. There are: V. arvensis Murray, V. metajaponica Nakai, V. odorata L and V. tricolor L. Species belonging to Viola sect. Viola - V. metajaponica and V. odorata - are perennial, with small, linear-lanceolate stipules and globose, non explosive capsules. Species belonging to V. sect. Melanium -V. arvensis and V. tricolor- are annual or biannual, with leaf-like stipules and erect, explosive capsules. Color and morphology of the flowers contributed to the species recognition. Seed characteristics as presence and mean size of the elaiosome and ornamental details of seed coat are here described. Foliar anatomy in transversal view of V. odorata and V. tricolor in relation to the tissue disposition and presence of characteristic cells of the epidermis is reported. Descriptions, illustrations, ecology and geographic distributions for all entities are given. A key to identify the species is also included. Finally, problems related with the misidentification and the identity of some species are discussed.