Sir

The questions raised by Peter D. Moore1 in connection with the discovery2 of the wild gametophytes of the celebrated British rarity, Killarney fern (Trichomanes speciosum) are of great significance. Moore questions the appropriateness of declaring a plant species extinct without being sure that the last individual has been wiped out. We would like to examine these issues in the Indian context, where the appearance of new taxa, extinction and rediscoveries go hand in hand.

It has been predicted that, in the next few decades, one-third of Indian biodiversity may become extinct or nearly extinct3. At present, the rarity of Indian plants is commonly inferred from herbarium data. If a species has not been collected within the past 50 years, it is considered ‘possibly extinct’4. This highly biased concept has led to the rediscovery of many ‘extinct’ plants when they were searched for thoroughly. Nearly 60 Indian endemic species have been rediscovered in this way during 1990-98, for exampleCynometra bourdillonii, Dialium travancoricum, Humboldtia bourdillonii, Inga cynametroides, Taeniophyllum scaberulum and Aenhenrya rotundifolia . Some papers report the rediscovery of more than a dozen ‘extinct’ species.

These rediscoveries are directly related to the amount of collecting effort invested, and we believe that most tropical (rather than temperate) ‘extinction’ is actually non-availability of data rather than genuine extinction. No Indian biologist has yet questioned the credibility of these reports. We suggest that the Indian plants classified as extinct because they have not being collected recently should instead be termed ‘plants to be rediscovered’. This may save the word ‘extinction’ from constant misuse.

Pointing out examples of plants that have been considered extinct but then re-established from seed banks, Moore suggested5 that monitoring of the soil seed or spore bank should be mandatory before designating a plant as extinct. But is this possible in a country such as India, where the search for the mature plant itself is a difficult task; where biodiversity documentation is incomplete; and where taxonomists themselves are ‘critically endangered’ owing to lack of funding6?