Print version ISSN 1405-2768
The floral anatomy of five species of Opuntia from Mexico is described and compared. Three to five floral buds (pre-anthesis) and flowers in anthesis were fixed and prepared using standard paraffin microtechnique. The most relevant results obtained confirm that the anatomical features of the pericar-pelo are similar to those of the vegetative stems; however, there are differences among species in the cuticle, epidermis and hypodermis. The external tepals in O. cantabrigiensis, O. decumbens and O. stenopetala have a papillose epidermis. The staminal filaments are free with an amphicribal bundle similar to that described for other members of the family. The nectary is of the hypanthial type. The Opuntia style has an open stylar cavity like that reported for Pereskia, but it is different from other dicotyledons. Moreover, epidermal cells of said cavity are occluded by tannins, a character shared with Pereskia and other genera of Opuntioideae. The results suggest it is necessary to study additional members of this genus to understand adequately the interspecific variation.
Keywords : floral anatomy; Opuntioideae; papillose epidermis; open style.