438 
WRIGHT : FOLIAR PERIODICITY 
leaf before the end of April. Yet at Buitenzorg this species 
commences to drop its old leaves in July, five to six months 
after those in Ceylon. 
Almost the same dissimilarity is seen in the fall of old 
leaf of Erythrina indica, at Peradeniya in January and 
February, and at Buitenzorg in July. This variation is 
analogous to the great differences in -time between the 
periodicities of trees at Peradeniya and in the Province 
of Uva, and is all the more interesting on account of the 
fact that the species concerned are common in both 
islands. 
There are several species which have been introduced 
to Java from Ceylon and to both islands from other 
countries, and the differences in their foliar periodicities 
are extremely interesting. 
One of the most surprising examples is seen in the 
behaviour of Schizolobium excelsum. At Peradeniya the 
leaf-fall is very regular every year, but at Buitenzorg it is 
as irregular as it can possibly be. Dr. Treub wrote that in 
trees of this species, from three to ten years old, the branches 
of the same tree behave in different ways, some being leaf¬ 
less for two or three months and others at the same time 
having their full fresh foliage. Dr. Treub wrote that the 
only way to explain such remarkable differences was to 
assume that the climate at Buitenzorg was so equal all the 
year that even branches of the same tree were able to 
follow their own “inspiration” and thus show their 
autonomy. 
Other equally noteworthy instances are seen in the 
behaviour of Hevea brasiliensis and Manihot Glaziovii, which 
at Buitenzorg. drop their leaves during July and August, 
but at Peradeniya during February and March. The differ¬ 
ences in the periodicities of other well-known species are 
obvious when one realizes that at Buitenzorg, Ficus religiosa, 
the Bo-tree, drops its leaves in March and Lagerstrcemia 
flos-reginæ in September. 
