XVI International Botanical Congess

Recently, it has been recognized that seasonal variation in insolation may determine of reproductive phenologies in the tropics. In wet forest at El Verde, Puerto Rico, average rainfall is >150 mm per month such that there is no dry season that would be adverse to seedling germination. Insolation is largely determined by sun angle and peaks in the months of May and August. Phenologies of over 50 species collected between April 1992 and June showed that most species exhibited peak flowering (75%) and fruiting (69%) in the months of May - September. No species exhibited peak flowering in the months of December and January and only two species peaked in fruiting during this period around the winter solstice. Thus, changes in seasonal insolation are correlated with seasonality of flowering and fruiting in this wet forest site.