GIANT BAMBOOS. 
217 
thus supported in their passage upwards, and the whole 
clump remains compact and resistant to the wind. As 
growth continues the young unbranched culms rise high 
above the bowed stems forming the remainder of the clump, 
and at this stage they are not unfrequently broken off by 
the force of the wind. As a rule they do not begin to droop 
until they are within a few metres of their full height. 
When a young culm arises close to an old trunk which is 
nearly vertical, it may run up quite parallel with the latter 
for a remarkable distance, so that the appearance is as if 
the old culm exerted a directive influence upon the young 
one. But there appears to be no reason for regarding this 
as actually the case. The fact was utilized, however, in 
making measurements of the growing culms. 
At Peradeniya the elongation of the culms takes place 
almost entirely during the south-west monsoon, which 
blows generally speaking from May until the end of Sept¬ 
ember. Branching begins about October or November, and 
the further development of the branches occupies the greater 
part of the north-east monsoon, October to April. In the 
case of different clumps a good deal of variation was shown 
in the time at which a corresponding stage of growth was 
reached. The culms of the oldest and largest clump 
examined (clump A) were also the earliest to begin and to 
complete their elongation. Other clumps were as much as a 
month later in this respect. 
Individual culms of the same clump reached the same 
height at periods differing by as much as a fortnight, or 
sometimes even more. It appears further that in different 
years elongation may begin at different times. Thus I find 
the following record in Trimen’s report for 1889 : “ The 
premature and excessive rainfall in April stimulated the 
giant bamboos to send up their culms a month or more 
before the usual time. They grew with great rapidity—one 
which Mr. Clark measured lengthening at a rate of 13^ inches 
in 24 hours.” The same authority states that in the previous 
