4 



Co?itributions to Indian Botany: 



[Jan. 



hence it is unknown on the plains of Coromandel, though not unfre- 

 quent in Mysore, but, so far as I have seen, only abounding, in the 

 peninsula, on the higher hills participating in the western monsoon, 

 which enjoy, during the hot months, a moderate range of temperature, 

 with a very humid atmosphere. Some, how many is not yet known, 

 are found during the monsoon on the Malabar coast, but little elevated 

 above the level of the sea, but, except in Tanjore, I have not seen one 

 of the order on the plains eastward of the ghauts, beyond the influence 

 of that monsoon : and the only one found there, is the Hydrocera 

 triflora, which grows, but is not common, in its ditches and swampy 

 grounds, during the cool season, and is the only place where I have yet 

 seen if,. 



This peculiarity of distribution may account for his not having met 

 with peninsular species, as he was but little in the southern provinces, 

 and perhaps they are not found in the eastern range of the northern 

 ghauts : but, twenty-two of the forty-seven species named by Wallich, 

 are from Silhet, Pimdooa and Nepaul, from all of which places Rox- 

 burgh procured plants, and one of the three he describes is from Silhet. 

 A moist climate and moderate temperature are the circumstances most 

 favourable, if not indispensable, to their production ; hence we find 

 twenty-two, of the remaining twenty-five species named by Wallich, 

 natives of the peninsula, but confined to the ghauts and Mysore where 

 these contingencies meet. This fact was first noticed by Mr. Royle, 

 who, after remarking the nearly equal division of the forty-seven 

 species between the frontier mountains of Bengal and the peninsula, 

 adds, " a singular equality of numbers, seeing that we have hitherto 

 found peninsular and South of India genera confined to the base of the 

 mountains, and if found existing on them, generally only as single 

 species ; but here we have them in equal numbers, some of them ex- 

 tending to an elevation of seven thousand feet. 



" This anomaly can only be explained, and a stronger fact cannot be 

 adduced in its confirmation, than that the moisture and moderate 

 temperature of the rainy season in the hills (for it is at this season 

 only that they are found) is as favourable to their growth as the heat 

 and moisture of the peninsula. I have never met with any in the 

 plains of India ; but have heard from travellers that they, are abundant 

 in Central India, whence we may expect some new species, as well as 

 from the Neilgherries." 



The facts which I have mentioned regarding the distribution of the 

 peninsular species, go to prove, that heat and moisture are not the 

 circumstances most favourable to their production here, but moisture 

 combined with a moderate but equal temperature. At Courtallum for 

 example, whence I have eleven or twelve species, they most abound in 

 shady places on the tops of the hills, with a mean temperature during the 



