138 LIVING PLANTS 



of seedlings of corn and date may proceed 

 so long as the necessary amount of plastic 

 material is available. 



In such manner many specimens each of 

 Arissema triphyllum, Calla palustris, Lilium 

 splendidum, Trillium erectum and T. erythro- 

 carpum, Isopyrum hiternatum, Oxalis Bori- 

 bunda and O. vespertilionis, Justitia sp., Hi- 

 biscus rosa-sinensis, Zea mais and Phoenix 

 dactylifera were grown. Of these it was 

 found that leaves of Arisasma perish in an air 

 free from carbon dioxide at the beginning of 

 the unfolding stage ; leaves of Calla, Lilium 

 and Trillium attain normal stature but are 

 incapable of further existence. Leaves of Zea 

 carry on normal development during a period 

 often to twelve days, but in this time attain 

 each a stature inferior to that of control 

 plants, and then begin to deteriorate. Leaves 

 of Oxalis, Isopyrum, Hibiscus, and Justitia 

 attained normal stature, and were capable of 

 continued existence at the expense of food de- 

 rived from storage tracts, or active chloro- 

 phyll-bearing tissues. 



In the ordinary course of leaf development 

 growth is carried from the rudimentary stage 

 to the unfolding of the lamina at the expense 

 of food derived from storage organs or from 

 the main axis. Ordinarily the supply of food 

 transported to the developing leaf is supple- 



