The present work is is the outcome of a series of field exploration and collection tours conducted to different parts of Garhwal Himalayas from the year 2001-2008. The collection trips were arranged in such a way so as to cover different seasons of the year and atleast important places. Detailed field observations were recorded in the field note book. Routine herbarium practices (Jain and Rao, 1977) have been followed in the collection of plant material and for preserving the herbarium specimens.
All the specimens were critically examined and identified with the help of floras, monographs and revisionary papers and were later determined in the herbaria (PAN, PUN, BSD, BSA, DD, CAL, LWG, K, BM etc.) with the help of eminent pteridologist working there. In presenting the flora the families are arranged according to Pichi-Sermolli (1977) system with minor modification (Ching, 1978; Kramer and Green, 1990). Kyes for families, genera and species are also included alongwith the detailed description of these. Citation of species is kept minimum. Illustration for maximum plants and also the photographs been provided. The description is followed by specimens examined, ecology, earlier records from the study area and distribution of the species, critical foot notes and taxonomic notes area also provided wherever needed. An extensive study in Chamoli and Rudraprayag districts leads to the conclusions that 256 species of ferns under 75 genera belonging to 36 families are present over here. Phytogeography of 256 species, 11 varieties, 1 hybrid, 1 forma and 2 subspecies occurring in the study area are compared to Nepal, Pakistan and different published regional floras of India. The description of fern habitats depicting ecology, population size, altitude is provided in detail. Ethnobotanical notes on various fern species from the study area are also presented. It is hoped that the present volume covering various aspect of the fern flora of Chamoli and Rudraprayag will be of immense use to students, researchers, teachers, forest personnel, horticulturists, nature enthusiasts and other scientists engaged in the documentation of the biological diversity of India.