The costs and controls of flowering and fruiting in {\it Spondias purpurea\/}

Small potted trees of Spondias purpurea were monitored to determine the costs and controls of flowering and fruiting. The effect of photoperiod, extremes in moisture and temperature, and defoliation were examined. The carbon exchange rates of the leaves, shoots and fruits were determined. Light response curves and diurnal levels were also investigated. $\sp{13}$Carbon labeling was used to determine which plant parts are carbon sinks. Photoperiod induces dormancy and bud activity. Extremes in soil moisture and temperature induce leaf fall. Flowers, fruits, and roots are carbon sinks. The results were used to develop a phenological model with latitude, soil moisture, and air temperature as variables. ^