Double- and single-seeded indehiscent legumes of Platypodium elegans: consequences for wind dispersal and seedling growth and survival.

Platypodium elegans (Leguminosae), matures indehiscent wind-dispersed fruits containing 1 or, much less commonly, 2 seeds. Relative to single-seeded fruits, double-seeded fruits have greater wet mass, area, wing-loading, and rate of descent in still air, and consequently are dispersed shorter distances under field conditions. The proximal seed of double-seeded fruits has a smaller dry mass and usually has lower and slower germination than the distal seed. Unless multiseeded fruits more easily escape seed predation, there is no apparent evolutionary advantage to a parent of P. elegans producing multiseeded fruits. Their presence in low numbers appears to result from incomplete elimination or suppression of development of the multiple ovules after pollination. -from Author