Tobgay and Kitichate Sridith

DOI: 10.14456/sjst-psu.2019.131

pp. 1037 - 1047

Abstract

The study conducted along the altitudinal gradient of 300-3900 m asl. recorded a total of 36 species (21 genera) and 46
species (29 genera) in study areas I and II respectively. The sighting of only one species each for the majority of genera,
including Pavetta L., Oldenlandia L., and Argostemma Wall., which are described as the largest genera of Rubiaceae, was
unusual. While the species with a narrow distribution range were found concentrated at the lower altitude exhibiting endemic
nature, the herbaceous species exhibiting maximum distribution range were dominant at the higher altitudinal range. The low
altitudinal hump-shaped distribution pattern was observed in both study areas. The higher diversity indicated by the ShannonWiener and Simpson diversity analysis was attributed to the moderate mean precipitation, temperature, and relative humidity.
The altitude and litter thickness contributed the maximum to the species composition and distribution pattern based on canonical
correspondence analysis.