ANATOMÍA FLORAL DE CINCO ESPECIES DE OPUNTIA (OPUNTIOIDEAE, CACTACEAE) DE MÉXICO

Abstract

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 pericarpelo 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.