NO. 53.-1902.] TREES AND FLOWERING PLANTS. 91 



From here the line passes on over very broken country to 

 the head waters of the Bentota river, and along that water- 

 way to the sea, which last forms the western limit. 



Within this wide sweep of embracing line is included a 

 number of large rivers, viz., the Kelani-ganga for a little 

 more than half its length, together with its most important 

 tributaries, the Maha-oya, the whole of the Kalu-ganga and 

 its branches, nearly the whole of the Walawe-ganga, and 

 the Bentota river, not to mention the Attanagalla-oya and 

 several large tributaries of the rivers already enumerated. 



The altitudes reached extend from sea level to over 7,000 

 feet, and consequently the variation of temperature ranges 

 from the burning heat of the south to often below freezing 

 point at the Horton Plains. 



The greatest change, however, is to be found in the 

 difference of rainfall. This at the lowest is about 45 inches 

 a year on the south-east limits of the Ratnapura District, 

 after which all gradations of humidity are passed, culmi- 

 nating in a rainfall closely approximating 300 inches in a 

 year in the valley of the Kalu-ganga to the north-west of 

 Ratnapura. 



The following points may be mentioned as indicating the 

 wide range of rainfall : — 





Altitude. 



Mean Rainfall. 





Feet. 



Inches. 



Colombo 



Sea level 



8831 



Negombo 



Sea level 



67-52 



Kalutara 



Sea level 



86-62 



Labugama 



375 



161-50 



Rayigam 



400 



165*88 



Henaratgoda Gardens ... 



33 



97-85 



Yeyangoda 



300 



97-19 



Gikiyanakanda 



200 



151-93 



Avisawella 



105 



131-80 



Dunedin 



400 



180-53 



Sembawatta 



1,6C0 



218-56 



Padupola 



1,636 



230-85 



Ratnapura 



84 



150-10 



Pelmadulla 



408 



142-70 



Aberfoyle 



3,300 



129-52 



€ 2 



