HABITAT AND PHYTOSOCIOLOGICAL CHARACTERS OF THE ENDANGERED PLANT SPECIES, EXACUM BICOLOR ROXB.

Abstract

Study on the phytosociological characters like distribution, abundance, density etc of a species in its established habitats is a tool to determine the effect of environmental conditions on variations in population characteristics. Based on this concept, four leaf shape variants (ovate, linear- lanceolate, oblanceolate and ovate – elliptic) of the plant species, Exacum bicolor distributed in four different grasslands habitats viz.,Payyanur, Taliparamba, Paithal mala and Thirunelli at Kannur and Wayand districts of Kerala were selected in the present study. The populations of the study species showed distinct expression of ecological attributes across the four leaf shape variants in four habitats studied. The distribution level determined through the annual mean frequency percentage was higher (89.29 %) in the populations of ovate leaf shape variant in Taliparamba, where as it was lower (5.71 %) in the populations of linear – lanceolate leaf shape variant in Payyanur. Similarly, the annual abundance of the population was higher (5.08/m²) for ovate – elliptic leaf shape variant (Taliparmba) and lower (1.43/m²) for linear – lanceolate leaf shape variant (Thirunelli). The annual density obtained by the population was also higher for ovate leaf shape variant present in Taliparmba (4.10/m²) and lower for the population of linear – lanceolate leaf shape variant present in Thirunelli, (0.09/m²). From these ecological studies, it is understood that among the four leaf shape variants, generally ovate leaf shape variant has established well. In addition, the grassland community at Taliparamba is determined to have most suitable microclimate also for this variant than the other habitats studied.