HH Risley of the Indian Civil Service, Calcutta, in his introduction to The Gazetteer of Sikhim, 1894, described the location of what was then a kingdom “tucked away on the northern border of Darjeeling, on one side, and two enormous spurs to the south of the Himalayas — the Singrilela and Chola ranges. These almost impassable barriers and gradually slope down on the southern side towards the plains of India”. Ensconced within Sikkim is a variety of flora that thrive in their unique order of distribution, determined by elevation. 

Sir JD Hooker (1817-1911), the greatest authority on Sikkim&’s and Darjeeling&’s  vegetation, wrote in his journal, Flora Indica, that Sikkim is divided into three zones — the lower, stretching from the lowest to 5,000 feet, which he referred to as the tropical zone; further to the temperate zone reaching to 13,000 feet, which is the upper limit of tree vegetation, on to the permanent snow line of 16,000 feet, the Alpine zone. He writes that up to 12,000 feet Sikkim has dense forest cover, interrupted by clearances signifying cultivation. 

Surprisingly, Hooker wrote that the description did not apply anymore to areas below 6,000 feet as, due to the increase of population, every suitable area of land was cleared for cultivation and trees only remained in rocky ravines and on very steep slopes where cultivation was impossible. But he confirmed that above 6,000 feet the status of vegetation remained unaltered. Hooker was a close friend of Charles Darwin, with whom he shared these notes.

Hooker&’s own collection of Sikkim plants during his tour of the place in 1849-1850 amounted to 2,920 species, of which 150 were ferns. The Gazetteer wrote that assuming  Hooker failed to collect 25 per cent from the total of about 4,000 species of  plants and ferns, the sum of all species of  Sikkim plants, his collection of 2,920 species as a figure was creditable and plausible as no botanist  could have possibly collected every plant species from the whole of Sikkim. 

Owing to the humid climate of the place, and the absence of excessive cold over a greater part of it, the prevailing vegetation is evergreen. 

We come to the predominant feature of Sikkim&’s vegetation — ferns. 

CB Clarke, also a botanist, wrote in 1879 that between Nepal and Assam there were a total of eight species of tree ferns and 248 other species of ferns, of which over 200 species were indigenous to Sikkim. Out of the eight tree ferns, five species thrived at the lowest levels and three lived between 3,500- 7,000 feet. Hooker wrote that tree ferns are graceful objects and form a striking feature on the landscape wherever they occur. 

They can be in small groups or in extensive groves and can attain a height of up to 30 feet. Hemitelia and Alsophila are the two genera of tree ferns in Sikkim. Some species have stripes, the part of the plant resembling a stalk armed with stout prickles. The pith from the stems of certain tree ferns are eaten by the Lepcha community and they also use the same substance to make "marwa beer" when the supply of marwa grain is exhausted. 

In the Rangeet valley, Hooker noted a handsome climbing fern, Aerostichum palustre, which clothes the trunks of tall trees. This will be an unusual but attractive sight for those who venture out to that valley on a trek. Among the large and more remarkable ferns growing on the ground, Hooker wrote that none excelled the Polypodium ornatum in beauty and it is always an object of admiration. Of Sikkim&’s 4,000 species of flora, the most alluring are the orchids that have adorned the locale with a tradition from pristine times. 

They decorate a rock, a shrub or even the uppermost boughs of a tree. In their mixture of hues, orchids define one of the many wonders of the natural world. The orchid family is extensively represented in Sikkim, with 350-400 species. Mind you, theres an estimated total of 5,000 species in the world. Although none of Sikkims orchids have flowers equal in size or colour to many South American species, yet several of its orchids are not at all inferior. There is an intrinsic difference in the two classifications of orchids. The epiphytal, which attach themselves to rocks or trees, and the terrestrial, which grow on the ground. A few are parasitical on roots of trees. 

In Sikkim, the epiphytal class are more numerous and better known. The Dendrobium, Coelogyne and Cymbidium are some of the better known varieties here. Hooker rated the Dendrobium genus, with about 40 species, the most popular of orchids; most of the species have large attractive flowers. The Nobile species seen from 1,000-5,000 feet is exceptional because it grows on trees and also on rocks, its white flowers tipped in purple as though they have been dipped in ink.

 The Corymbosa, a predominantly snow white-coloured flower, is seen up to 9,000 feet. Due to orchids requiring a specific elevation, Hooker and others found that these plants did not survive for more than a couple of years in Kolkata. The Phajus Wallichii, a fine Sikkim ground orchid, is an exception and thrives in Kolkata, much to the delight of horticulturists. 

The species has inspired many enthusiasts to travel in search of this orchid, with one thought in their minds: See you anon, Sikkim.