Morpho-anatomical characterization and conservation status of the Whisk Fern Psilotum nudum (L.) P.Beauv. (Polypodiopsida: Psilotaceae) from Cooch Behar District of West Bengal, India

The district Cooch Behar of West Bengal, India is considered a unique zone for pteridophytes. The Whisk Fern Psilotum nudum (Family Psilotaceae), one of the primitive members of living vascular plants considering its age of evolution during the Devonian, is reported to occur in the Cooch Behar District. The present study has been designed to investigate the current conservation status as well as to describe the morphological and anatomical features of the epiphytic species. The present study revealed that the natural falling of old aged host trees and cleaning and white painting of host tree trunks lead to habitat destruction which may lead to extinction of the species from the studied areas. During the field visits, a new site of the occurrence (Madan Mohan Temple of Cooch Behar City) of the species has also been recorded. Plants are perennial and pendent in nature. The rhizome is achlorophyllous, freely branched, and covered with rhizoids. The aerial stem is up to 36 cm long, repeatedly dichotomously branched and chlorophyllous. Leaves are scalelike, without any midrib, lanceolate to ovate, and without ligules. Synangiums are composed of three connected sporangia, bearing numerous bean-shaped spores. Stele in rhizome is haplostelic type; while, it is actinostele in the aerial stem. Morpho-anatomical description of the species has been documented for the first time from West Bengal and has enriched the botanical information of the species. Proper conservation of the taxa is utmost necessary in order to maintain their population in natural habitat.