WEIGHT : FOLIAR PERIODICITY 
functions in plants, the characters and periodicities of which 
are to a great extent controlled by the adversities of the 
climate in which the plants and their ancestors have lived. 
In this paper an account of observed foliar activities of 
known endemic and indigenous arborescent species in 
Ceylon, and their variation in the same or different climates 
is given; the adaptability of introduced species will be 
dealt with in a subsequent paper. Exact information of 
the foliar periodicities of trees in the tropics has been 
repeatedly asked for by Ursprqng, Schimper, and others who 
have worked at the subject of tropical vegetation. It is only 
by the possession of snoh information that the question of 
internal factors in plant life in equable or tropical areas can 
be determined. 
The investigation has also been carried out to determine 
annnftU* enTironment in a ‘ropical area affects the 
“I P6ri0d o£ 1 “ a —»» The information 
snelts 8leane<i fTOm 3 ^ ° £ 
rr;; . 
“***"** onsn^Ctheses* 
number of dlTonT “ " b6ing decidn <™' ^ 
foreign one.) is only (e “ Inding 
