CONICET | Buscador de Institutos y Recursos Humanos

Floral venation patterns in three species of Sapindaceae-Paullinieae. The floral venation patterns of Cardiospermum grandiflorum, Urvillea chacoensis and Thinouia mucronata, are surveyed. These species are monoecious and the inflorescence is a thyrse carrying staminate and bisexual flowers funcionally pistillate. Cardiospermum grandiflorum and U. chacoensis belong to the subtribe Paulliniinae which is characterized by obliquely zygomorphic flowers, whereas T. mucronata belongs to the monotypic Thinouiinae which presents actinomorphic flowers. Vascular pattern is similar in both types of flowers of the studied species; from one ectofloic siphonostele depart vascular traces that supply the perianth whorls displaying phenomena of progressive fusion and adnation. Vascular tissue supplying the nectaries is characterized by strands of phloem. Regarding the floral vasculature in these species, differences in the vasculature lay primarily in the number of the sepal-petal complexes traces departing from the central ectophloic siphonostele; whereas the venation pattern of the fertile verticils is common to them. The data obtained support the basal position of Thinouia in the tribe Paullinieae.