Diversity and distribution of herbaceous vascular epiphytes in a tropical evergreen forest at Varagalaiar, Western Ghats, India

Herbaceous vascular epiphytes were screened in a total sample of 13 445 tre es (in 153 species) and 348 lianas (in 30 species) greater than or equal to 30 cm girth at breast height in a 30 ha plot of tropical evergreen forest at Varagalaiar, Indian Western Ghats. Of these, 4.3% of trees and 3.7% of l ianas were infested with epiphytes. Epiphyte diversity totaled 26 species i n 19 genera and 10 families. Sixteen species were angiosperms in three fami lies (Orchidaceae 54%; Piperaceae and Araceae 8%) and 10 species (38%) were pteridophytes in seven families. The orchid, Pholidota pallida was most ab undant and occurred on 178 (29.6%) stems. Asplenium nidus occurred on the m aximum of 62 host species. The species richness estimators employed for spe cies accumulation curves after 100 times randomization of sample order have stabilized the curve at 18th and 19th hectares respectively for Incidence- based Coverage Estimator and Chao2. A total of 588 trees and 13 liana stems lodged epiphytes, 74% of which were evergreen species and 26% deciduous. E piphyte density was greater (56%) in deciduous species (Bischofia javanica 30% and Vitex altissima 8%). A significant positive relationship was found between trunk size and epiphyte association. Larger epiphyte species occurr ed mostly on middle and larger stems and smaller epiphyte species occurred on smaller stems. The majority of epiphytes (92%) were of autochorous dispe rsal type, bearing capsule or dust diaspores, while the remaining species w ith berries and nutlets are dispersed by small vertebrates.