IN CBYLON. 
435 
met with when the 
Peradeniya and the 
le of Careya arborea 
then deal with the variation of indigenous species when 
grown in other countries. 
The most conspicnons differences i 
foliar periodicities of plants common 
Uva District are considered. In the 
we find that at Peradeniya the leafless stage is passed through 
in February or March, but at Passara in the Uva District it is 
usually during May and June. 
Trees of Ficus Arnottiana, though passing through their 
stages of foliar activity at Peradeniya in March and April, 
show in the Passara and Lunugalla districts a production of 
new leaves and flowers in May and June. 
Again trees of Gyrocarpus Jacquinii, though they undergo 
defoliation at Peradeniya during Febrnary and March, do 
not pass through the leafless stage until May to July in the 
dry parts of the Northern Province. In each case we find 
that defoliation occurs during the dry hot weather, and the 
variation in the climates already described will alone account 
for the change in the periodicity of these species. These 
examples can be used in support of the contention that the 
time of defoliation is associated with the external factor of 
climate. 
Many instances can also be quoted to prove that there is 
considerable variation in districts which have relatively 
similar climatic periodicities, but which show slight differ¬ 
ences of rainfall, temperature, and humidity. The differences 
in plant phenomena in such districts cannot in every case be 
assigned to the slight differences of climate, because we know 
that even in the same district the same species may exhibit 
considerable variation in manner and time of foliar periodi¬ 
cities. 
Trees of Terminalia belerica usually drop their old leaves 
in February and March at Peradeniya, but at Ambalawa 
near Gampola I have seen leafless trees during the first week 
A still better example is Been in trees of Albizzia 
stipulate. In the Peradeniya district the leafless phase 
