IN CEYLON« 
427 
Roxb., by Brandis. Brandis in his Forest Flora of India 
states (p. 149) that Dalbergia Sissoo drops its leaves from 
December to February, and remains leafless until April, 
but that though young trees are occasionally leafless for a 
few weeks, old trees are hardly ever without leaves. 
There are some cases, in which the trees undergo defolia¬ 
tion and pass through a leafless stage in their first year ; 
this has been observed with trees of Eriodendron anfractu- 
osum, with suckers of Bombax malabaricum, and cuttings 
of Erythrina indica. Trees of Castilloa elastica undergo 
defoliation in their second year ; but trees of Tectona grandis, 
Bassia longifolia, and Couroupita guianensis do not pass 
through a leafless stage in their second year. Trees of 
Hevea brasiliensis become defoliated in their third year, 
Cassia nodosa in their fourth, and Poinciana regia and Ficus 
religiosa in their fourth or fifth year. There are very few 
recorded observations available for most of our deciduous 
species, but in most of them it is quite possible that the leaf¬ 
less stage is not passed through until the trees are more 
than one or two years old. 
The fact that defoliation during the first year of a plant’s 
life is characteristic of quick-growing species, and that 
slower-growing trees do not become leafless during the first 
few years suggests that there may be a relative constancy 
between the amount of foliage and the first period of 
leaflessness. 
The frequency of Defoliation of Trees . 
I have been surprised to notice that certain trees, 
apparently old and vigorous, which were classed as ever¬ 
greens, have during certain years (some only once during 
four years’ observation) begun to drop their leaves and have 
undergone a complete renewal of foliage. Kurz* remarks 
that in the evergreen forests of Burma some trees lose their 
leaves after a certain number of years. Warming, when 
* T. Kurz : Flora of British Burma, Vol. I., 1877. 
