A study of the vegetative and reproductive features of the podostemaceae of Kerala rivers

Abstract

Podostemaceae is a unique family of Angiosperms comprising rheophytic, herbaceous members with thalloid plant body. The plants are distributed in the tropical and subtropical fresh water streams and water falls. The vegetative and reproductive features of the members of the Podostemaceae in Kerala have been studied with particular reference to the taxonomy, distribution and ecological variations. The work is mainly based on an on the spot study of the plants and observations in the laboratory. Most of the rivers in Kerala originating from the Western Ghats receive North-East and South-West monsoon rains. Therefore, the members of the Podostemaceae thrive well in these rivers. One new species (Zevlanidium maheshwarii Mathew and Satheesh) and a new combination [Podostemum munnarense (Nagendran and Arekal) Mathew and Satheesh] are described. Keys to the genera and species of the Podostemaceae of Kerala have been prepared. Polv~leurum stvlosum which exhibits the highest degree of polymorphism has been classified into different ecotypes on the basis of distinct morphological features. Ecotypes are suggested for the species Podostemum subulatum too. Various aspects related to this family have been discussed in detail.