18 RELATION BETWEEN CLIMATE AND VEGETATION 



as various congeners, yields the " Bikli" poison of E. Nepal, Sik- 

 kini, and Bhotan. Thalictrum, one species. Ane7none vitifolia, 

 Fumaria, two Viola;, Stellaria, Hypericum, Geranium two 

 species, two Balsams, Epilobium, Potentilla, Paris (7000 to 

 10,()U0 feet), Panax pseudo -ginseng, and another species, Me- 

 coiiopsis Nepalensis, two species of Gentiana, Ligularia, and 

 two Craivfurdice, two species of Ariscema, Anagallis, Hemi- 

 j)hragma, and Ajuga, Disporum, and three Convallarice, one 

 with vertioillate leaves, whose root is called another " Bikh," and 

 considered very virulent. GraminecB were very few in number, 

 but a large Carex covered the ground, amongst the bamboo. 



Still tlie absence or rarity of several very large natural families 

 at this elevation, which have numerous representatives at and 

 much below the same level in the Western Himalaya, indicates a 

 certain peculiarity in Sikkim. These are the following : — Ra- 

 nunculacecE, Fumarice, Cruciferce, Alsiiiece, GeranicE^ Legu- 

 mi?iosce, Potentilla, Epilobium, Crasstdacece, Saxifragece, Um- 

 helliferce, Lonicera, Valerianece, F>ipsacece, various genera of 

 Compositce, Cumf>anulacece, Loheliacece, Gentiance, Boraginece, 

 Scropliularinece, Prirmdacece, Gramitiece. 



All the above ai'e genera of the north temperate and subarctic 

 zones, which affect a much higher level in this part of Sikkim 

 than in the Western Himalaya or Bhotan — the difference in 

 this respect being very much greater than the small disparity of 

 latitude will account for, or tlian the (if there be any) difference 

 of mean temperature, for the snow-line is certainly very little 

 different here from that of the N.W. Himalaya. On the other 

 hand, certain tropical genera are more abundant in the tempe- 

 rate zone of the Sikkim mountains, and ascend much higher 

 there than in the Western Himalaya. Of this fact I have cited 

 conspicuous examples in the palms, plantains, and tree-fern 

 ascending to nearly 7000 feet, and in the presence of many other 

 orders at great elevations, as figs, peppers, Lauri, tfec. ; and to 

 these could be added many others, none more remarkable than 

 Balanophora, bf which there are several species above 4000 and 

 even 6000 feet, one ascending to 11,000 feet. 



This ascent and prevalence of tropical species is due to the 

 humidity and the equability of the climate in this temperate 

 zone, and is perhaps the direct consequence of these conditions. 

 An application of the same laws accounts for the extension of 

 similar features so far beyond the tropical limit in the Southern 

 Ocean, where various natural orders which do not cross the 30th 

 and 40th parallels of N. latitude, are extended to the 55th in 

 Tasmania, New Zealand, the so-called Antarctic Islands south 

 of that group, and to Cape Horn itself in Fuegia. 



The forest region, encroaching so far upon, and in fact cover- 



