IN CEYLON. 
479 
Sterculia Thwaitesii, Mast. 
Terminalia parviflora, Thw. 
Dipterocarpus zeylanicus, Thw. 
Hydnocarpus venenata, Gaertn. 
Doona cordifolia, Thw. 
Semecarpus Gardneri, Thw. 
Debregeasia Wallichiana, Wedd. (=D. zeylanica, Hk.). 
Ficus infectoria, Roxb. (endemic ?). 
The total number of observed deciduous endemic species 
is therefore only 17, or less than 3 per cent, of the 
arborescent flora, or 6 per cent, of the endemic trees in 
Ceylon. Though the percentage number of deciduous 
indigenous species is higher than this, it is nevertheless 
small, and the vegetation therefore be regarded as mainly 
evergreen throughout the island. 
Distribution of deciduous endemics .—The distribution of 
the deciduous endemic species is of considerable interest. 
From the facts related when discussing the question of trans¬ 
piration and the curves showing an agreement between the 
defoliation of the deciduous species and the dry hot months 
of February and March, one may be inclined to anticipate 
that the endemic deciduous species would be wholly or 
mainly confined to the dry hot parts of the Island, and that 
very few would be common in the cooler moist districts. The 
distribution of the deciduous endemic species is, however, 
practically confined to the moist or very wet districts, only 
one species having been recorded for the dry and interme¬ 
diate zones, viz., Sterculia Thwaitesii, Mast. These facts 
strongly suggest that the defoliation of species confined to 
Ceylon is not vitally associated with a high temperature or 
low humidity. They also compel one to realize that the 
foliar periodicity in the dry zones is one characterizing 
species which are not limited to this Island, but distributed 
throughout various climates in the tropical world. 
It is advisable to give a detailed statement of the periodicity 
of this group, and the smallness in number of the species 
concerned allows one to do this. 
