MILLER, J. S. University of Arizona, Department of Ecology & Evolutionary Biology, Biological Sciences West, #310, 1041 East Lowell, Tucson, AZ 85721. - The evolution of gender dimorphism in Lycium (Solanaceae).
Gender dimorphism has evolved at least twice in the Solanaceous genus
Lycium. In the North American dimorphic species, male-sterile
plants (i.e., females) have flowers with a long style equal to or
slightly exserted from the corolla tube and abortive anthers, while
perfect-flowered plants (i.e., hermaphrodites) have a style of
variable length with a set of long, fertile anthers equal to or
exserted from the mouth of the corolla tube. Several important
characters associated with the evolution of gender dimorphism are
highlighted and discussed in the context of the evolution of gender
dimorphism. In this group, polyploidy appears to have triggered the
evolution of gender dimorphism by disrupting the self-incompatibility
system, leading to inbreeding depression and invasion by male-sterile
mutants.
Key words: gender dimorphism, gynodioecy, Lycium, polyploidy, self-incompatibility, Solanaceae