ENDEMICS AND PSEUDO-ENDEMICS IN RELATION TO DISTRIBUTION PATTERNS OF INDIAN PTERIDOPHYTES

摘要

Of c. 530 Pteridophytes reported as endemic to India (about half the total number of known Indian species) in recent decades, the great bulk are mistaken, particularly those from the Indo-Himalaya. Only 47 endemic Indian ferns, less than 10% of the previous total, are accepted here. But this includes a few that are doubtfully endemic, mainly due to unresolved taxonomic doubt, or because they may be expected to occur in adjacent Countries. Thus 8 are taxonomically dubious, requiring further study, and 7 more, all but one from N.E. India, may possibly be expected elsewhere outside India. The c. 483 mistaken pseudo-endemics arose mainly due to naming of erroneous "new species" thought to be endemic, or due to not knowing the range of species outside political India, combined with insufficient investigative taxonomic research.Previous reports of endemics are listed and their status is reappraised along with a new list or accepted endemics. In contrast to previous conclusions, nearly all endemic Indian Pteridophytes are Peninsular to S. Indian ferns (27, plus 5 more taxonomically dubious), with far fewer N.E. Indian (6, all of which may possibly be expected elsewhere outside India) and W. Himalayan (3, plus I more taxonomically dubious); the floristically Malesian Nicobar Islands have 3 (plus 2 more taxonomically dubious). These numbers are only to be expected as N.E. India is an intimate part of the Sino-Himalayan and S.E. Asian flora, connected without barriers to Tibet and China or to Myanmar by two mountain chains, while S. India is more isolated geographically since more ancient times and has a partly Malesian fern-flora. Some details of Indian endemics in relation to phytogeographical elements are given.Two new combinations are made, Selaginella adunca subsp. albocincta and Diplazium pseudosetigerum. Endemic species : Huperzia - 1, Selaginella - 9, Isoetes - 1, Osmunda - 1, Arthromeris - 1, Phymatosorus - 1, Oreogrammitis - 2, Trichomanes - 1, Pteris - 1, Cyathea - 3, Lindsaea - 3, Asplenium - 3, Thelypteris - 3, Athyrium - 2, Tectaria - 1, Dryopsis - 1, Dryopteris - 3, Polystichum - 4, Bolbitis - 3, Elaphoglossum - 3.