Orchid treasures of the Sikkim Himalayas
Lauren Gardiner, Research Fellow in Conservation Science at Kew, reveals some of the intriguing orchids that can be found in the remote Indian state of Sikkim.
A haven for orchids
Nestled high up on a map of India, far above the hot flat plains, and tucked between Nepal, China, and Bhutan, is a tiny state called Sikkim. Once a separate kingdom of its own, Sikkim became a protectorate of India in 1950, and later a full state in 1975. Home to the third highest mountain in the world, Kangchenjunga, within an area of just 7,096 km2 Sikkim contains snow-capped mountains, glaciers, and alpine valleys in the north and tropical forests in the south – providing a wide range of different habitats for plants and animals to thrive in. The tiny state is so remote and difficult to access that it remains a haven for the more than 500 different species of orchids found there, relatively undisturbed by the activities of humans.
Searching the kingdom for botanical treasure
In 1898, botanists George King and Robert Pantling published what remains the definitive orchid reference for the state, The Orchids of the Sikkim-Himalayas. Documenting the presence of 449 species, with descriptions, altitudes, flowering times, and line drawings of each species, there is a hand-coloured first edition of this monumental work in the Library at Kew. Trained local people searched the kingdom for orchids and sent plants down to the West Bengal town of Mungpoo, near Darjeeling for Pantling to illustrate and King to describe.
Surviving extreme conditions
The striking Dendrobium nobile is the state flower of Sikkim, and has the distinctive long thin jointed stems (referred to as canes) of many members of the genus Dendrobium. The flowers of Dendrobium nobile are pale to deep purple-pink with a characteristic dark velvety centre. These orchids, like the majority of Sikkim’s orchids, grow as epiphytes, on the trunks or on the branches of host trees. Growing like this, with their roots exposed, epiphytic orchids have to endure some extremes in conditions – when it rains, they get drenched and must take up the water they need, but in between they are completely exposed and must be able to tolerate long dry periods too.
Another epiphytic orchid found in Sikkim is Coelogyne cristata. The large frilled white blooms of this species have a golden yellow throat and hang down from clumps of small rounded pseudobulbs. These pseudobulbs store water to enable it to survive during the dry season, and it flowers after the monsoon rains, when the humidity rises but the temperatures are still cool, as it prefers higher altitudes than Dendrobium noble.
Not all orchids in Sikkim are epiphytes and some of the most attractive are the various Pleione species which grow terrestrially and in thick moss on trunks and rocks. Pleione species are able to grow at much higher altitudes than their epiphytic relatives, as they can tolerate freezing temperatures. The rounded to triangular pseudobulbs narrow at the tip and each bulb, having produced one or two leaves during the growing season, is replaced by a new active bulb each year. One of Sikkim’s species is Pleione hookeriana, named for Kew’s second director, Sir Joseph Dalton Hooker (1817-1911), who was one of the first western botanists to explore Sikkim and who discovered a great many plant species, including orchids and Rhododendron species, on his travels.
Threatened slipper orchids
Some of the most intriguing, but most rarely seen, orchids are the slipper orchids, including those in the genus Paphiopedilum. The dramatic flowers always draw a lot of interest from visitors to Kew’s Orchids Festival, and one such species is Sikkim’s Paphiopedilum fairrieanum.
Known from only a few restricted locations, including a single grassy but precipitous cliff in Sikkim, the species is so threatened with extinction (mostly from collection by unscrupulous modern-day plant hunters) that it is considered to be Critically Endangered in the wild.
This species was first described, as were all of the Sikkimese species mentioned above, by the Victorian ‘Father of Orchid Taxonomy’ John Lindley (1799-1865). John Lindley received and identified orchid specimens from around the world and described more than 6,000 orchid species over the course of his career. A friend and colleague of both Sir Joseph Hooker and Charles Darwin, Lindley’s extraordinary collection of more than 7,000 orchid herbarium sheets and illustrations, and much of his correspondence with other botanists of the day were bought by Kew and form the basis of Kew’s world-renowned orchid research collection for orchids.