OF CEYLON AND INDIA. 
279 
Ilowers.'" The development of the flowers takes place 
during the high water of the last two months of the year, 
and by the middle of December the flowers are generally 
completely formed, ready to open as soon as exposed to 
the air. 
The general life-history at Peradeniya is then briefly 
this : the seeds are shed upon the rocks in January and 
February, germinate in April ; the plants reach their full 
vegetative development in September and October, and 
develop their flowers subsequently ; the flowers are exposed 
to the air by the fall of the water at the beginning of the 
dry season, and the exposed plants wither and ultimately 
die. 
Hitherto the life-history of these plants has never been 
thoroughly investigated, all descriptions having been written 
from, material collected at the flowering season. During the 
greater part of their life the plants are deeply submerged in 
violent torrents of usually muddy water, and their study is 
a matter of difficulty and even of danger ; during the height 
of the monsoons it is practically impossible to get at them. 
Fortunately, however,, there are often periods when the 
water-level is lower for a short time, and by combining these 
periods over several years I have been so fortunate as to be 
able to work out the complete life-history for most of the 
Ceylon forms, with the exception of the development of the 
floral shoots towards the end of the year. 
Podostemaceæ are found abundantly in all districts of 
India and Burma, where there is rain in the south-west or 
summer monsoon, but on the whole their vegetative season is 
shorter than in Ceylon, and the more so the farther north we 
go in each region, the rains beginning later and ending earlier 
in the year. The following tables of rainfalls in various 
localities where Podostemaceæ have been found (taken 
* If submerged again within a very short time, rejuvenescence takes 
place, new growing points being formed behind the withered portion. 
