Pharmacognostical studies on an endemic spike moss Selaginella tenera (Hook. & Grev.) Spring have been carried out on the materials collected from Tirunelveli hills, Western Ghats, South India. Results of detailed morpho-anatomical and physico-chemical studies have been presented. Morphologically this species is distinct in having erect habit, heterophyllous leaves both on vegetative and reproductive parts. The vascular bundles in stem, rhizophore and roots are protostele. The preliminary phytochemical screening shows the presence of phenolic group, steroids, triterpenoids, tanninsa and sugars. All the morpho-anatomical and physico-chemical characters this endemic species will be useful to distinguish the species from other spike mosses from Western Ghats.