REPRODUCTIVE ECOLOGY OF SOME TROPICAL HERBACEOUS WEEDS

摘要

Six weed species, namely, Sida acuta, S. cordata, S. cordifolia (Malvaceae), Triumfetta rhomboidea (Tiliaceae), Cleome gynandra and C. viscosa (Capparaceae) were studied with reference to their floral biology, sexual systems, pollination and reproductive success. Sida species exhibit almost the same flowering phenology, floral morphology, floral biology, sexual system, breeding system, pollination system, fruiting behavior and seed dispersal. They attract bees, wasps and butterflies to their flowers.The bees use these plants as principal pollen source while wasps and butterflies as nectar source during which they contact the anthers and stigmas and pollinate the flowers. Sida species are hymenopterophilous and psychophilous. In all Sida species, the flowers facilitate delayed autogamy. Rain-assisted autogamy may also occur. Fruits mature quickly, split apart and disperse seeds into the air. The seeds possess the characteristics that are adapted to dispersal by wind, humans, animals and rain water.