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 1 899-1900 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 

 1 899-1900 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. 



