MEMOIRS- OF THE NEW YORK BOTANICAL GARDEN, 



59 



by unusual variations in temperature. No marked periodicity could 

 be detected in the rate of growth in the dark room kept at a constant 

 temperature although slight fluctuations 

 were seen. Similar irregular fluctua- 

 tions in the rate were observed in the 

 growth of the prophyll in darkness. The 

 fluctuations in the dark room might be 

 accounted for partly by the daily addi- 



FlG. 17. Arisaema triphyllum. Grown in diffuse 

 light. 



Fig. 18. Arisaema tripliyllum. Adult 

 plant after confinement in dark room 

 two weeks. 



