| - Sinopse:
Flower buds of the winged bean (Psophocarpus tetragonolobus [L.] DC) growing in Teresina, Piauí, Brazil reverted from their normal sexual reproductive function to a photosynthetic vegetative function. In comparison with normal flowers, reverted flowers were characterized by a transition from a tetragonolobanous to a digonolobanous form (100% of samples observed) and by virescence of flower parts (99.4% of samples obwerved). Reversion was further characterized by vivipary which depends on the degree of evocation (i.e. induction) of vegetative buds to flower buds and on foliation of reverted ovules in flowers. Statistical analysis of data from field experiments indicated a single gene, in the homozygous recessive form in all reverted individuals, to be the genetic basis of this reversion phenomenon.