82 CLIMATE AND VEGETATION OK 



§ VIII. Calyx of 5 membranous sepals. Corolla salver-shaped, 

 tube slender, short, cylindrical, lobes flat, spreading. 

 Stamens 6 to 8, within the tube. Style short. Ovary 

 5-celled. — A small scaly shrub. 



28. R. antJiopogon, Don — the only species. 



If from a consideration of the species themselves we turn to 

 that of the country they inhabit, it will be found that a great 

 part of it is characterized by perennial humidity^, which is exces- 

 sive during the summer months. It will be seen, also, that the 

 degree of humidity varies in different parts of the country, and 

 that the rain-fall is unequally distributed ; also that elevation is 

 to a great degree a relative term, equal altitudes having different 

 climates in various parts of Sikkim, with a dissimilar vegetation. 

 To explain these points, it is necessary to give some account of 

 the natural features of the Sikkim Himalaya Mountains, which 

 seem to be little known, or generally misunderstood by those who 

 have sought information respecting the management of Ehodo- 

 dendrons, through the various horticultural periodicals. Except 

 these points are clearly understood, it will be impossible to 

 appreciate the conditions under whicli the species grow. 



Sikkim is included in a section of the Himalaya Mountains 

 about sixty miles broad from east to west, where it is bounded 

 respectively by the mountain states of Nepal and Bhotan. Its 

 southern limits are easily defined, for the mountains rise rather 

 abruptly from the plains of Bengal, as spurs of 6000 to 10,00Q 

 feet high, densely clothed with forest to their summits. The 

 northern and north-eastern frontier of Sikkim is beyond the 

 reo^ion of Rhododendrons, and is not a natural but a political line, 

 drawn between itself and Tibet. Sikkim is nearly due north of 

 Calcutta, and only 400 miles from tiie sea at the Bay of Bengal ; 

 its latitude being 26" 40' to 28" N., and longitude 88° to 89" E. 

 The greater part of the country between Sikkim and the sea is a 

 dead level, occupied by the delta of the Ganges and Burrampooter, 

 above which the slope is so gradual to the base of the mountains, 

 that the surface of the plain from which the Himalayas imme^v 

 diately rise is only 300 feet above the sea. The most obvious 

 effect of this position is, that the prevailing southerly wind 

 reaches the first ranges of hills loaded with vapour. The same 

 current, when deflected easterly to Bhotan, or westerly to Nepal 

 and the north-west Himalaya, is intercepted and drained of much 

 moisture, by the Khassya and Garrow Mountains (soutii of Assam 

 and the Burrampooter) in the former case, and the Rajmahal hills 



