342 SEIFRIZ: THE TALIPOT PALM AT PERADENIYA, CEYLON 
3. In 1918 there flowered simultaneously in the Peradeniya 
Gardens in Ceylon three species. of monocarpic plants, Corypha 
umbraculifera, Dendrocalamus giganteus, and D, sirictus, and a © 
fourth species, Bauhinia anguina, which, while not monocarpic, 
flowers rarely. This remarkable instance of gregarious flowering 
was immediately preceded by a ‘‘drought”’ of such mildness 
that, when it is compared with other droughts of previous years 
which did not arouse the plants to anthesis, it cannot be regarded 
as the direct cause of this unusual simultaneous blossoming of - 
three widely differing genera, all of which flower only after 
many years of purely vegetative growth. 
4. At the time that the talipot palms, with other monocarpous 
and rarely flowering plants, were in blossom at Peradeniya, 
there was also in flower in the Buitenzorg Gardens in Java a 
talipot palm which had, every month of its life, been drenched 
in rain. Droughts are unheard of at Buitenzorg where even a 
normal dry season.is a rarity (10). 
5. There lives in Burma today a forest of Saas poly- 
morpha covering hundreds of square miles, which has, since 
1853, flowered sporadically in restricted and scattered areas. 
The forest as a whole has not flowered in these seventy years, 
although subjected to repeated droughts (10). 
There is another case of gregarious anthesis which, though 
not in plants of monocarpic habit, has an interesting bearing on 
the problem of the possible effect of external environment on 
simultaneity in flowering. In the orchid, Dendrobium crumena- 
tum, the time of the simultaneous appearance of the flowers is 
apparently due to a climatic influence occurring eight days in 
advance of the flowering. The environmental stimulus is com- 
monly associated with, but not always accompanied by, rain 
(2 and 10). It is here suggested that this factor is possibly a 
humidity stress. High humidity may well occur without rainfall 
while it is always present with rainfall. It should be emphasized 
that it is the ime of flowering rather than the simultaneity 
itself which the humidity stress determines. The simultaneiry 
is due to an inherent characteristic of the orchids (10). 
On the basis of the foregoing data it seems reasonable to 
conclude that gregarious flowering in bamboos and palms is not 
determined by drought but rather by a germinal factor. If an 
environmental complex exists which is responsible for simul- 
