IN CEYLON. 
467 
belerica, Cassia nodosa, Bridelia retusa, Lagerstrcemia Flos- 
reginæ, and numerous others give a barren appearance to the 
arborescent vegetation. With certain exceptions the decidu¬ 
ous trees seem only to recognize one dry period as against the 
alternating dry and wet months of the remainder of the 
year. Terminalia Catappa undergoes a complete change of 
leaf during the dry part of each monsoon, and other species 
are probably subject to foliar depletion twice during certain 
years. 
Another fact which points to the effect of the Ceylon 
climate on foliar periodicity is seen in the behaviour of 
trees in the north of the Island. The majority of the Ceylon 
species of Diospyros are evergreen and grow in the wet and 
intermediate zones. There are two species, viz., D. montana, 
Roxb., and D. ovalifolia, Wight, which in the dry hot 
district between Madawachchi and Mannar are partially 
deciduous and pass through a semi-leafless phase prior 
to the beginning of the rainy season ; yet they are evergreen 
at Peradeniya. 
That the climate of Ceylon has a decided influence on the 
periodicity of the deciduous species is obvious if one leaves 
the Peradeniya district in May and proceeds to the north of 
the Island, where there is very little rain in the south-west 
monsoon, and where the weather from January to October 
is relatively dry and hot. The defoliation and foliar reple¬ 
tion have been considerably delayed in the Vavuniya and 
Mannar Districts compared with Peradeniya, the species 
common to all districts dropping their leaves at times which 
differ by many weeks and months. In the northern districts 
so long as the plant drops its leaves during any of the eight or 
nine months the same climatic advantages, if any, will 
accrue. 
The maximum number of species undergoing defoliation 
is always found to be coincident with the dry period in 
all parts of Ceylon, and it is not necessary to do more than 
refer to the various observations recorded in the section 
