Nayar, M.P. & Sastry, A.R.K. 1990. Red Data Book of Indian Plants. Vol. 1-3. Botanical Survey of India, Calcutta.
This book has been serving as the epitome for those looking for Red Listed Plants of India.
On account of 2.5 decade of its publication, I was thinking if some work is out/ in progress to update the book.
Reliable and accessible online resources will be highly appreciated.