Pollen morphology of Nymphaea Linn.

Pollen morphology of nine species and six ecotypes of Nymphaea has been analysed using LM and SEM. The pollen grains are trimorphous with monocolpate, megaporate and trichotomocolpate forms occurring individually or in combination in the different taxa. The exine surface is dominantly verrucate showing different distributional patterns forming areolate to sparsely verrucate, and with modifications of these excrescences, which are connate or surmounted by protuberances. The pollen types are diagnostic at species and ecosystem levels, and appear to be of taxonomic and evolutionary significance in the genus. However, these variations may be attributed to adaptations to ecological conditions.