Himalayas are home to more than one-third of all types of rhododendrons

Key highlights-

• The publication titled ‘ Rhododendrons of Sikkim and Darjeeling Himalaya- An Illustrated Account’  lists 45 taxa of rhododendrons (36 species, 1 subspecies, 1 variety, and 7 natural hybrids).
• There are 132 taxa (80 species, 25 subspecies and 27 varieties) of rhododendrons found in India. Of the 45 taxa recorded in the publication, 24 are found in the Darjeeling Himalayas and 44 in the Sikkim Himalayas.
• Darjeeling and Sikkim Himalayas comprise only 0.3% of India’s geographical area but the region is home to one-third (34%) of all Rhododendron types. 
• This highlights the ecological significance of the region as far as an indicator species like Rhododendron is concerned.
• Of the 45 taxa documented by BSI, five are facing a high threat due to anthropological pressures and climate change, according to scientists. 
• The Rhododendron edgeworthii, with white campanulate flowers, recorded a huge habitat decline in both Darjeeling and Sikkim. 
• Rhododendron niveum, with big purple flowers, found in the Lachung area of north Sikkim is facing threats due to rampant constructions. Rhododendron baileyi, Rhododendron lindleyi and Rhododendron maddenii are also threatened.

About Rhododendrons-

• Rhododendron, meaning rose tree in Greek, is considered an indicator species for climate change. 
• The BSI in 2017 published  Rhododendron of North East India: A Pictorial Handbook, suggesting that there are 132 taxa (80 species, 25 subspecies, and 27 varieties).
• The flowering season for rhododendrons starts in March and continues till May. However, recently, flowering was found to begin as early as January for some species. 
• This is an indication that those areas are getting warmer and the phenology of rhododendrons can be an important indicator of climate change.
• It also has a prominent place in the country’s botanical history. Rhododendrons were first recorded by Captain Hardwick in Jammu and Kashmir in 1776 where he spotted the  Rhododendron arboreum. 
• However, it was a visit by the British botanist Joseph D. Hooker to Sikkim between 1848 and 1850 that revealed the rhododendron wealth of the Sikkim and Darjeeling Himalayas.
• The first species of Rhododendron from northeast India — Rhododendron dalhousiae was reported from Sikkim by Hooker in 1848 in his book The  Rhododendrons of Sikkim Himalaya. 
• This publication almost 160 years ago made these flowers very popular in the western world and resulted in the horticulture boom in Europe.
• The BSI publication has a number of historical references to the contribution of British botanists Joseph D. Hooker and David G. Long as well Indian botanists and researchers S.T. Lachungpa, U.C. Pradhan and K.C. Pradhan among others. 
• These people played a crucial role in discovery and identification of Rhododendrons in Sikkim and Darjeeling Himalayas.