THE FAMILY OF LEMNACEAE IN VENEZUELA

Resumo

During a trip to the northern part of Venezuela in 2005 about 70 samples of Lemnaceae have been collected. Together with the results of herbaria studies it was possible to construct distribution maps of the respective Lemnaceae species in Venezuela. Fifteen species are recognized from which four have been recorded newly: Landoltia punctata, Lemna obscura, Wolffiella neotropica, Wolffia globosa. Out of these species, W. neotropica  is endemic in the northeastern part of South Ame rica. The other three species are probably introduced. Three species of the resting 11 are only known from neighbouring countries in South America, but have not been recorded from Venezuela. For each species a morphological characteristic with key for determination is given and geographical and ecological distribution is shown. Phytosociological relevés have been recorded. Four associations are recognized.