^ :hai'. II] PERIODIC PHENOMENA IN TUP: TROPICS 251 



lo Sul blossom at intervals of about thirteen years. Bambusa arundinacea, 

 in the west coast of Cisgangetic India, blossomed at intervals of thirty-two 

 ears — 1X04. 1836, icS6S '. According to Ridley, two species of Hopea, 

 ^. intermedia and H. Mengarawan, and four species of Shorea, S. lepro- 

 ula, S. parvifolia, S. pauciflora and S. macroptera, blossom with great 

 egularity every sixth year. These cycles are said to coincide with very 

 ry years -. 

 In most cases, during the greater part of the reproductive period, tliere is 

 retardation or even a stoppage in the vegetative domain, and this may 

 xtend to the whole crown, when its habit is to break simultaneously into 

 ower, or it may be confined to the larger or smaller branches, according 

 D their degree of individuality. The effect on the vegetative region is 

 ■equentl)- limited to the discontinuance of the formation of foliage-shoots; 

 le vegetative buds rest. In many cases, the antagonism between the 

 cgetative and reproductive functions goes further. A tree or shrub pre- 

 'iriiig to blossom throws off its foliage, chiefly however from the floxvering 

 ■anchcs. whereas the purely vegetative ones usually retain their leaves. 



At what stage of the development of blossom this phenomenon happens I have 

 nfortunately omitted to determine, and the literature of the subject has nothing 

 ) say about it. In this case, as in the shedding of the foliage of Urostigma gla- 

 ;llum ', the effect possibly depends on the diversion of the transpiration-current 

 wards the flower-buds. The fresh foliage sometimes shoots out at the com- 

 lencement, sometimes at later stages of the formation of the fruit. 



Criiger had already observed in Trinidad that Erythrina blossomed 

 hen bare of leaves and that twigs that remained flowerless retained their 

 iliage. I have frequently had an opportunity of seeing this statement 

 jnfirmed and have observed the same fact repeatedly in Schizolobium 

 igantcum in Java. I met with similar phenomena in the botanic garden 

 f Tjibodas, where I paid more attention to it, in Parasponia parviflora, 

 le richly flowering twigs of which threw off the greater part of their 

 iliage, whilst those that bore only a few flowers retained considerably 

 lOre leaves. I also noted it in an Ardisia and in Juannuloa aurantiaca, 

 here the blossoming twigs were altogether or nearly leafless, whilst a 

 :duction in the foliage was not exhibited on the purely vegetative twigs. 



I found also in many otherwise deciduous trees that the flozoering twigs 

 'quired their leaves later than did the purely vegetative ones. Thus, on 

 ovember 21, 18H9, in the botanic garden at Buitenzorg, I saw two trees 



Firmiana colorata with young leaves and flowers. The flowers were 

 Jundant on one of the trees and scanty on the other, but in both cases 

 ere confined to separate systems of branches. On the flowering boughs 



' Brandis, II, p. 90. ^ Ibid. p. 20. 



^ See p. 245. 



