Anatomie florale de Maripa (Convolvulaceae-Erycibeae). [Floral anatomy in Maripa (Convolvulaceae - Erycibeae)]

Floral anatomy was studied in two Maripa species (M. axilliflora and M. violacea) to complete our knowledge of flower morphology in Erycibeae, a basal tribe in Convolvulaceae, and to assess gynoecial evolution within an ontogenetical frame work previously defined in Ipomoeae s.l. Several parallels can be established with primitive Solanaceae, especially Cestreae, both in pedicel and stamen histology and in receptacle vasculature. The anthers lack placentoids whereas, the presence of oxalate packages at the level of the stomium is reported for the first time in Convolvulaceae. They gynoecium retains some archaic characters reminiscent of Humbertia, such as a well developed placental pedestal, and a nectariferous disk wholly embedded in the ovary wall. An apical septum is lacking in M. axilliflora but is present in M. violacea. Evolutionary gynoecial acceleration may be suggested both in vasculature and in ovarian outline, combined with a trend specific to the tribe towards the loss of a style, enlargement of the stigma, and disappearance of the septum.