XVI International Botanical Congess

Pollen grains of many anemophilous gymnosperms have 1-3 air-filled sacci, which have been thought to confer greater flight range. Using electron microscopy, the saccate pollen of three extant conifers (Pinus, Falcatifolium, Dacrydium) has been examined. Several morphological characters have been incorporated into a computer model that calculates flight properties for the grains. The model has been tested by stroboscopic photography of actual pollen. Using the model, structural data can be incorporated from fossil pollen to predict how the grains may have flown. Although recent studies indicate that sacci have a buoyancy function once grains reach a pollination drop, the present study provides the opportunity to further evaluate the adaptive significance of saccate pollen by correlating structural and aerodynamic features.