FLORAL BIOLOGY AND POLLINATION OF SOME MO NOCOTYLEDONS IN A VENEZUELAN CLOUD FOREST

Floral biology and pollination mechanisms of 33 herbaceous monocot spe cies were studied in the tropical cloud forest of Henri Pittier Nation al Park, Venezuela. The frequency distribution of pollination systems was as follows: cantharophily (35.1%), ornithophily (24.3%), melittoph ily (16.2%), myiophily (10.8%), anemophily (8.1%), and chiropterophily (5.4%). Of 71 visiting species recorded on 33 plant species, 67.6% we re pollinators and 32.4% were only visitors; coleopterans and dipteran s were the most diverse groups. Studies of floral biology showed that 46.9% of the species were monoe cious-dichogamous and 53.1% were herma phroditic -adichogamous. Among adichogamous species, 15.6% were herkog amous. The pollination units were the flowers or inflorescences in her maphroditic and monoecious species. Bat-, bird-, and bee-pollinated sp ecies produced nectar, although pollen was also found as a reward in b ee- and bat-pollinated species; beetle pollination was associated with floral parts as the reward. Floral longevity of vertebrate pollinated species ranged from 10 to 24 hours; floral longevity for bee-pollinat ed species was similar or longer than for vertebrate-pollinated specie s. For cantharophilous and wind-pollinated species, pollination unit l ongevity was increased by the longevity of the female flowers. These d ifferent patterns in time of anthesis, floral longevity, and pollinato r species, together with vertical and horizontal species distribution, are mechanisms that promote pollination specificity and intraspecific pollen transportation in the understory cloud forest.