Endemics and Pseudo-Endemics in Relation to the Distribution Patterns of Indian Pteridophytes

Abstract

Of c. 530 Pteridophytes reported as endemic to the India in recent decades (about half the total number of c. 950-1000 known Indian species), the great bulk are mistaken, particularly those from the Indo-Himalaya. Only 47 endemic Indian ferns, less than 10% of those reported previously, are accepted here. But this figure includes several that are rather 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 a further 7, all 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. In the present paper previous reports of endemics are listed and their status is reappraised along with a new list of accepted endemics. Quite opposite to previous conclusions, the great majority of endemic Indian Pteridophytes are peninsular-Indian to south-Indian ferns (27, plus 5 more taxonomically dubious), with far fewer being N.E. Indian (7, all of which may possibly be expected elsewhere outside India) and W. Himalayan (2, plus 1 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. 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.