38 THE HERBARIUM OF THE 



of a purely Egyptian Flora in Sindh, of a Polynesian Flora in Malaya, 

 and of numerous African types in the mountains of the Madras Penin- 

 sula. It may interest Indian botanists, for whom especially this little 

 paper is intended, to give a slight sketch of the different Floras which 

 co-exist within the limits of British India. 



Disregarding for a moment the Malayan Peninsula, British India 

 may be described as an equilateral triangle with sides 1500 miles in 

 length, the apex advancing far within the tropics, the base in the hotter 

 part of the temperate zone. The tropical portion of this triangle is 

 traversed by ranges of hills of moderate elevation, most lofty toward 

 the south, where they rise above 8000 feet, less lofty in the north, 

 where the average height of the ridges is not more than 4000 feet. 

 Within the temperate zone the level of the surface is much lower, and 

 it is there occupied by the basins of two great rivers : the Indus on the 

 west and the Ganges on the east. South of the tropic this large tri- 

 angle is everywhere surrounded by sea, but north of the tropic the 

 boundaries of India are traced on land, and are more or less artificial. 



The Indian Peninsula includes two distinct mountain-systems. The 

 meridional chain of the Ghats attains in Travancore and Malabar an 

 elevation of 8000 feet, but north of Nagar rarely more than 4000. It 

 runs parallel to the western coast, and sends off transverse chains run- 

 ning east, which are flattened out into a table-land highest in the south, 



i 



where tlie continent is narrow, lower to the north, where the continent 

 is wider and the rivers larger. North of the Godavery the transverse 

 range of the Vindhia runs from sea to sea, almost on the tropic, sending 



■ 



out on all sides table-topped branches, and connected by a low ridge 

 with the Ghats further south, and with the Himalaya by the curious 

 oblique Aravvali range, which forms a water-shed between the Indus 



and Ganges. 



An extensive plain, watered by the Indus on the one hand and by 

 the Ganges on the other, separates the Indian Peninsula from the 

 Himalaya, which rises on the north, a stupendous barrier, constituting 

 the Indian portion of the enormous mountain-mass of Central Asia, 

 which presents steep declivities in all directions. 



After the configuration and elevation of the land, the most impor- 

 tant element by which the distribution of vegetable forms is regulated, 

 is climate. The climate of India depends mainly on the rain-fall. 

 Situated entirely in the northern hemisphere, and with an enormous 



