STRITTMATTER, LARA* and VIVIAN NEGRON-ORTIZ. Botany Department, Miami University, Oxford, OH. - Consolea corallicola (Cactaceae): a sexually dimorphic species with only one morph remaining?
Consolea Lem., subfamily Opuntioideae, comprises nine species
endemic to the Caribbean region. Within this genus, C.
corallicola Small. is a species with a single remaining wild
population of only 12 individuals on Little Torch Key, FL. Floral
morphology indicates that this species is hermaphroditic. The flowers
produce viable pollen grains, but rarely set viable seeds. When seeds
do initiate they do so by agamospermy. Embryological studies show that
although the flowers begin as hermaphrodites, at anthesis the ovules
are aborted and papery. During sex differentiation, the
megagametophytes are characterized by an excessive presence of starch
grains, indicating abortion. The anthers have a normal developmental
process, resulting in viable pollen grains. The study suggests that
these superficially hermaphroditic flowers are functionally staminate,
and that all surviving individuals are males. Therefore, we
hypothesize that C. corallicola had a cryptically dioecious
system, which we have also found in other Consolea species. The
female sexual morph is, apparently, extinct.
Key words: Cactaceae, Caribbean, conservation, Consolea, cryptic dioecy, embryology