CHLOROPHYLL AND GROWTH 135 



sion of their area ensues. The removal of 

 concurrent members results in an exaggerat- 

 ed extension of the petiole, but has no effect 

 on the laminae. A similar result is obtained 

 with the spathe under both conditions. It 

 is to be noted that in light the removal of 

 concurrent organs results in an increased 

 development of the laminae, and in darkness 

 of the petiole. 



Calla palustris is a plant consisting of a 

 creeping rhizome one to two centimeters in 

 thickness, from the apex of which arise a few 

 cordate leaves with petioles fifteen to twenty 

 centimeters long and one or more solitary 

 scapes eight to fifteen centimeters high. The 

 relativel^^ large rhizomes are filled with stored 

 food. 



Plants brought into a warm house and 

 placed under the apparatus described above 

 exhibited a development of the petioles and 

 laminae during a period of ten to twelve days 

 thatresultedin the formation of perfect leaves. 

 The continued existence of the plant, however, 

 under such conditions was impossible because 

 of the destruction of the stored food by fer- 

 mentation. 



In the dark chamber the slight extension of Results 

 the petioles occurred while the laminae attained with Calla 

 a size equal to those in the open air, although 

 they were recurved at the margins. No effects 



