16 RELATION BETWEEN CLIMATE AND VEGETATION 



teinber these absolutely swarm, and are no less troublesome to 

 man than to the feet of the ponies. 



The rain continuing heavily, we rested the men by some large 

 pools on the flat. A small Lobelia, Chrysosplenium, Procris, 

 and CaUitriche formed a sward on the banks, amongst which 

 some RauiDicuU grew {diffusus, Wall., and a similar species). 

 A large and handsome Carex flourished in the water. 



Rauniiculus, though so common a genus literally almost every- 

 where else, is extremely scarce in the temperate and tropical 

 zones of the Sikkim Himalaya ; R. sceleratus abounds in the 

 plains close to the foot of tlie hills, but between that elevation 

 and 10,000 feet I have nowhere seen this or any other species. 

 Here, and probably elsewhere in the Himalaya, the genus is very 

 rare in these zones, though more abundant in the arctic zone 

 above. 



CrucifercE is another natural order very frequent in the tem- 

 perate and mountainous regions of all the world, except the Sikkim 

 Himalaya. A variety of Cardamine liiisuta? is absolutelv the 

 only plant of this order occurring wild between the plains of India 

 and the summit of Tonglo. 



CompositcE again are far from represented on the scale thev 

 are everywhere else. Though about Darjiling, where clearances 

 have been effected, the amazing prevalence of Gnaphalmm and 

 Auaphalis. &c., gives an appearance of usual abundance of Com- 

 positcE, these very species will be found elsewhere scarce in the 

 temperate zone of southern Sikkim. 



Labiatce are also poorly represented, except in clearances. 



As far as I can guess, this paucity of representatives of orders 

 for which the temperature of the Sikkim Himalaya is admirablj' 

 adapted, can best be attributed — (1.) to the uniform luxuriance 

 of the arboreous vegetation, and the absence of either precipices 

 or naked spots of any kind. (2.) to the htmiid atmosphere ; 

 for some of these groups, as LeguminoscE , arc very rare in equally 

 temperate climates which, in respect of humidity and equabilitv 

 of temperature, can be compared with Sikkim, namely, New 

 Zealand and Fuegia. There, as here, Cruciferce, Compositce, 

 Ranunculi, Labiatce, and above all, LeguminoscE and grasses, 

 are very rare in the forest region. 



Our ascent to the summit was by the bed of a watercourse, 

 now a roaring torrent, from the heavy and incessant rain. A 

 small Anagallis (like tenella) and a scapeless Primula grew 

 by its bank, also some small Carices, and Hemiphragma. 

 The top of the mountain is another flat ridge, with depressions 

 and broad pools or small lakes, in which grew an Iris. A square 

 platform, raised by the Surveyor General (whose party were the 

 only Europeans wiio had previously to ourselves visited this 



