At least 1,049 new species of flowering plants have been added to the State’s flora in the past three decades.
Flowering Plants of Tamil Nadu, A Compendium, a book published by the Care Earth Trust, a Chennai-based biodiversity research organisation, has comprehensive details of flowering plants distributed across Tamil Nadu.
At present, there are nearly 6,723 species of flowering plants, including wild and cultivated or invasive species, found in the State. The 1,400-page book with rich illustrations took three years of research and data collation for taxonomist D. Narasimhan and his co-author Sheeba J. Irwin.
Funded by the National Biodiversity Authority of India and the Tamil Nadu Biodiversity Board, the book has exhaustive details, including nomenclature, flowering seasons, plants’ life forms and other information on medicinal and horticultural significance.
“We have included species’ English and Tamil names wherever possible and their distribution in the State, India and the world. We found that nearly 53% of the species found in the State were herbaceous (which have characteristics of herbs). This includes all kinds of grasses. Nilavembu is one of the herbaceous plants with more than 30 species,” said Prof. Narasimhan, retired associate professor, Department of Botany, Madras Christian College, and adviser, Care Earth Trust.
Worrisome trend
One of the worrisome trends is that 36% of the flowering plants in the State were cultivated or invasive species introduced, which may prove detrimental to the native varieties. Ipomoea Nil, a species of morning glory that was dense in the Nilgiris is becoming common in plains too, he said.
Similarly, invasive alien species of flora, wattle trees introduced from Australia and lantana have covered hilly regions like Kodaikanal and Nilgiris, choking native species. Noting that the Madras High Court had formed a committee to remove the invasive species, Prof. Narasimhan said: “We cannot avoid invasive species. But we must know how to keep them under check and not let them affect native species. For instance, the native variety of Ponnanganni greens (Alternanthera Sessilis) has been replaced with invasive varieties of Ponnanganni in northern Tamil Nadu.”
Tamil Nadu is home to 292 endemic plant species, such as Impatiens Tamilnadensis at Theni Hills and Sonerila Kanniakumariana endemic to the Kanniyakumari Wildlife sanctuary. These species need conservation efforts.
While new species have been added in the State, there are a number of species that have disappeared too. “We have recorded about lost species in the book. Rhynchosia Beddomei, a herb commonly called Beddome’s Snout Bean that was found in Chengalpattu and Diospyros Undulata or Walker’s Ebony earlier found in Coimbatore are among them,” he said.
The book, which is awaiting launch, would be a one-stop reference material and tool for conservation efforts. It would be made available in libraries, research centres and all educational institutions, said Care Earth Trust’s managing trustee Jayshree Vencatesan.
