202 



POPULAR SCIENCE MONTHLY 



tropics are a region of big things and the herbaceous plants make little 

 impression on the visitor. At the Peradeniya garden, the writer noted 

 a small area of perhaps half an acre that had been neglected for a 

 time. Here, although there were many tree seedlings started, there 

 was a fairly good patch of weeds — enough to make a lonely American 

 feel quite at home. These weeds were chiefly Lantanas and some of 

 our American composites, particularly the fleabane Erigeron and also 

 Conyza, 



It would be difficult to find elsewhere in the world an area the 

 size of Ceylon, or even much larger, with so many different vegetation 

 regions. The differences in these regions are brought about largely by 



Pig. 6. Laboratory and Herbarium. At the far right is the office of the director. 



From a photograph by the author. 



the winds which determine the distribution of rainfall and by altitude 

 with consequent temperature changes. The wet weather comes with 

 the rains from two different directions. The northeast monsoon com- 

 mences in October and brings heavy rains throughout the higher parts 

 of the island and in the lowland country of the northeast. A series of 

 rains continues through November and December, with a rather light 

 rainfall during January, February and March. In April the wind 

 changes to southwest and there is more rain, with June especially wet. 

 From then until October the rainfall is again lighter. It will be seen 

 then, that in the highlands it is always moist, but that there are certain 

 districts which have a rather pronounced dry season. The driest parts 

 of the island are in the north and the south or northwest and south- 



