ibclogo XVI International Botanical Congess


Abstract Number: 3575
Session = 3.10.7


CRYPTIC DIOECY IN TALL MEADOW RUE (THALICTRUM PUBESCENS): WHO'S FOOLING WHOM?


Keith Karoly, Reed College, Portland, OR, USA.


Thalictrum pubescens is a cryptically dioecious species, with female plants making stamens with sterile pollen. The function of female stamens was examined at a field site in NY state. Insect floral visitors discriminate on the basis of stamen number, with males visited more than females. Emasculated females received the fewest visits. Female pollen is deposited on stigmas, but does not interfere with the fertile, male pollen. Females were found to be pollen-limited. Stamen removal from all flowers on females did not decrease their seed production, however. Natural variation in stamen number was also unrelated to female reproductive success. Females from which insects were excluded set seed, suggesting wind can be a pollen vector. Female stamens do not appear to currently aid female reproductive success, and it is likely that female stamens persist for non-adaptive reasons.


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