Pollination Intensity and Seed Set in Trichanthera gigantea (Acanthaceae)

Abstract

Counts of pollen grains on the stigmas of individual flowers of Trichanthera gigantea in Central Panama were related to seed set. At least eight grains were necessary for fruit set in this species and mean seed set per fruit was less than one (of a maximum of eight). Less than 50 percent of the flowers (108 of 277) received eight or more pollen grains and, of these, only 5 1 set fruit. These results suggest that pollination limits seed production by this species at this site.