The Gregarious Flowering of the Talipot Palm, Corypha 
umbraculifera, at Peradeniya, Ceylon * 
WILLIAM SEIFRIZ 
The extent to which the activities of a plant are determined 
or influenced by the environment has long been a subject of 
discussion and investigation among botanists. There are those 
(6) who maintain that “‘every life process must to some degree 
be dependent upon the external world,’’ while others (11) hold 
to the belief that many vital phenomena are innate and, within 
certain limits, independent of the environment. _ 
The problem of the possible influence of environmental factors 
on the activities of a plant assumes an especial interest in 
connection with the gregarious flowering of monocarpous plants 
of long life cycle. There are species of bamboo which flower 
gregariously over large areas after 32 years of a purely vegetative 
life. This habit is also characteristic of the talipot palm, Corypha 
umbraculifera. 
There is a popular belief, which has received some support 
from scientific circles, that the phenomenon of simultaneity in 
flowering of monocarpous plants of long life cycles is due to 
drought (7). The writer has collected data bearing on this 
hypothesis and has found little evidence to support it. What- 
ever effect drought may have on gregarious flowering it is rela- 
tively slight, certainly not sufficient to be regarded as the ulti- 
mate determining factor of the phenomenon. The following 
data, previously collected, support this point of view: 
1. The simultaneous flowering throughout the mountains of 
Jamaica in 1918 of the climbing bamboo, Chusquea abietifolia, 
whose vegetative life extends over a period of 32 or 33 years, 
was preceded not by a drought but by two years of rainfall 
which was above the average (8). 
2. The gregarious anthesis of extensive forests of the bamboos, 
Dendrocalamus strictus and Bambusa arundinacea, estimat 
to cover in some instances areas of over a thousand square miles 
in India, is also not always preceded by a drought (10). 
* Contribution from the Osborn Botanical Laboratory, Yale University. 
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