This month's bicentenary of the birth of Joseph Dalton Hooker, one of the great botanical explorers of the nineteenth century, is a good time to highlight the urgent need to document India's remarkable biodiversity for conservation purposes (see also J. Endersby Nature 546, 472–473; 2017).

Hooker's compilation, The Flora of British India (1872–97), was the first, and is still the most authoritative, account of flowering plants in the country, which at that time included present-day Pakistan, Bangladesh and parts of Myanmar. Hooker corresponded with Charles Darwin on the 100 species of Himalayan Impatiens (balsams) he found (see go.nature.com/2sdxeby), new species of which are being discovered even now.

In his 1855 book Himalayan Journals, Hooker remarked on the vast stretches of dense forest in Darjeeling and Sikkim. Expanding populations, infrastructure development and climate change have since reduced these to a patchwork of fragments.

Botanists in India today are equipped with digital tools and facilities for fieldwork undreamed of by Hooker. Time is running out for them to produce a complete and authenticated list of the country's plants and to document plant-associated ecosystem services for the benefit of India's people and the world.