Abstract
The growth of ketak was influenced by genetic and environmental factors. In growth, ketak needs other plants as a climbing host plant, so information on the diversity of plant species in their natural habitat was very important. This research was aimed to identify composition and biodiversity of species in the natural habitat of ketak. This research used purposive systematic sampling by survey technique based on altitude i.e. 0-249, 250-499 and 500-750 m asl. There are 10 of observation plot with dimension of 20 m x 20 m at each altitude and total plot was 30 plots. The results showed that the composition at the seedling level at each altitude was 15 species in 11 families; and 13 species in 11 families and 8 species in 6 families. And at the tree level at each altitude there was 15 species in 10 families and 17 species in 14, and 9 species in 8 families. The value of the species diversity index (H ') at the seedling level in all altitude classifications was known that in medium categories, the index of species richness (D) in medium categories, only at the altitude of 500-750 m asl was in low category, and the index of species evenness (E), at all altitudes in the stable category. The value of the species diversity index (H ') at the tree level in all altitude classifications was known that in medium categories, the index of species richness (D) in medium categories, only at the altitude of 500-750 m asl was in low category, and the index of species evenness (E), at all altitudes in the stable category.