323 



Observafions on Botany^ S^c. 



[Oct. 



valuable timber tree wbicb might we doubt not be introduced to 

 any extent into our alpine districts. 



For the attainment of greater precision in our ideas respectint^ 

 the vegetation, as connected with the climate of successive eleva- 

 tions, Mr. Royle divides the southern slope of the Himalayas into 

 three belts; the first supposed to extend to between 4000 and 5000 

 feet of elevation ; as Sv vera! tropical perennials extend to the latter, 

 and snow rarely falls below the former The second belt may be 

 supposed to embrace the space between 5000 and 9000 feet, as the 

 winter snow is alwoys melted before the accession of the periodical 

 rains in May and June, and is nearly the limit to which herbacious 

 plants of tropical genera extends. The third belt includes all be- 

 tween this and the limit of perpetual snow. 



The flora of the first of these belts as already mentioned, is partly 

 European, but principally tropical, and extends over a great part of 

 India: that of the second still retains many tropical forms, but the 

 European ones now preponderate. Of both we possess many repre- 

 sentatives in our alpine flora as the following lists extracted from 

 Mr. Royle's work will show. It is necessary to premise, that the 

 bounds assigned to these belts are in a great measure arbitrary, for 

 the chang-es both in the temperature and the vegetation are so gra- 

 dual, that it is impossible to draw any clearly defined line, a 

 difficulty which is increased by the productions of similar elevations, 

 changing the farther we penetrate into the Himalayas, owing to the 

 line of perpetu.il congelation rising higher on the northern than 

 on the southern slopes, or rather on the interior than on the exterior 

 ranges, a fact well ascertained, but not easily accounted for. The 

 vegetation also differs on the same range or even mountain, so that 

 a straight line running' along the summit of the ridge, may be seen 

 dividing luxurient arborious vegetation on the northern face, from 

 brown barren grassy covering on the southern. 



Tropical genera 

 common to the Hi- 

 malayas andPenin- 

 tala. 



Fnropean genera 

 common to the Hi- 

 malayas and Pen- 

 insula. 



European and 

 Himalayan genera 

 not yet found in 

 the Peninsula. 



Natural Orders 

 having European 

 genera common to 

 the Himalayas and 

 Neelgherries. 



Canna 



Hedycbium 



Commelina 



Tradescantia 



Begonia 



Osbekia 



Meiaiitoma 



Ulmus * 



Fuonemus* 



f^hamnas* 



Rhus* 



Ilix 



Andromeda 

 Rhododendron 



Pinus 



Taxns 



JuniperuB 



Quercus 



Acer 



Carpinus 



Betuia 



Ranunculaceoe 



Cniciferce 



Violareos 



Caryophylleoe 



Hypericineoe 



Geraniacece 



Umbellifdrce 



