Feb., 1923] 
SEIFRIZ — CAUSES OF GREGARIOUS FLOWERING 
97 
the observations of Kurz in Burma where an unexpectedly large number of 
bamboos were collected in flower “ during [italics mine, W. S.] the two dry 
seasons of 1868 and 1869.” Brandis further quotes Kurz as stating “that 
in the Calcutta Botanic Garden there never had been so many species in 
flower as in 1874, which was a year of great drought ” (10, p. 14). It will be 
noticed that the abundant flowering of the bamboos in the Calcutta Garden 
occurred in 1874, i.e., during the year of great drought, and that the supposed 
stimulating conditions did not act upon the plant “at least a year before 
the flowering” actually took place, as Brandis elsewhere maintains must 
be true. 
To go further back than the favorable monsoon of 1900, i.e., to go back 
more than a year previous to the flowering of the bamboos in 1901, involves 
the question whether or not meteorological conditions, occurring more than 
a year before the appearance of the vital process which they are supposed 
to initiate, can be taken into consideration. It seems hardly likely that 
bamboo plants which flowered in early 1901 and whose flowering was 
preceded by a favorable rainy season in the mid-year of 1900 should have 
flowered as a result of a drought in early ‘1900. Not only Kurz, whom 
Brandis quotes, but others who have ascribed the gregarious flowering of 
bamboos to drought, have spoken of the flowering as occurring in times 
of drought. 
Owing to the severity of the drought of 1899-1900, we cannot altogether 
ignore the possibility of the unfavorable climatic condition having initiated 
in the bamboos of northern India a physiological process which did not 
become externally evident until a year and a half later (in the simultaneous 
flowering of the bamboo forests in 1901). Once the marked change in the 
physiological state of the plants was initiated, a subsequent favorable 
climatic condition (the monsoon of 1900) would be of no effect. 
The question cannot be conclusively answered. It is possible that the$ 
extreme drought of 1899-1900 of the Central Provinces of India had a 
telling effect on the bamboos of that region. But that the drought was 
the cause of the simultaneous flowering of the bamboos is not, in the face 
of other data, a possible deduction. The most that can be said is that when 
bamboos are near their time of reproduction an unusually dry season may 
have the effect of accelerating the formation of flower buds. 
Whatever our decision regarding the possible effect of the drought of 
1899-1900 on the general flowering of Dendrocalamus strictus in the Central 
Provinces of India in 1901, we have the definite fact that Bambusa arundi- 
nacea flowered gregariously in India in 1899 in the absence of a drought for 
at least five years previous to the flowering. 
Another interesting bit of evidence against the theory that drought is 
the cause of gregarious flowering in bamboos of long life cycle is to be found 
in the behavior of an immense bamboo forest region in Burma. The bam¬ 
boo in this case is of another species (. Bambusa polymorpha) than the two 
(Dendrocalamus arundinacea and D. strictus) we have just been considering. 
