• Macior, Lazarus Walter

Dense 2,000 m2 stands of Asclepias syriaca L., A. incarnata L, and A. verticillata L. in southeastern Wisconsin were studied for their pollination relationships with larger wasps and social bees. Frequency, kind, and position of pollinia attached to insect bodies were tabulated and correlated with cinematographic records of insect behavior on flowers. The frequency of Bombus species on Asclepias and other genera of the local flora was tabulated. The significance of floral moiphology, insect morphology, and insect behavior in Asclepias pollination and possible hybridization is discussed.