MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



53 



were made in absolute darkness. It was noted, however, that etiola- 

 tions made in the small portable dark chambers, which were ex- 

 amined daily in an exposure 

 to sunlight for two or three 

 minutes showed a different 

 stature for the leaves. In 

 such instances the laminae 

 were extended in a plane 

 and had a superficial area of 

 about half that of the nor- 

 mal. This result has been 

 verified by repeated obser- 

 vations and suggests that 

 etiolative reactions must be 

 accepted with caution unless 

 known to have been secured 

 in a total exclusion of day- 

 light. This caution takes on 

 special emphasis from the 

 fact that such vitiated etiola- 

 tions may not show the pres- 

 ence of chlorophyl. Sachs' 

 criterion of perfect etiolation 

 is therefore not one which 

 may be depended upon in all 

 species. (See Fig. 12.) 



The scape of the flower 

 showed excessive elonga- 

 tion and the spathe did not 

 reach normal size, the great- 

 est decrease being located 

 in the overarching hood. 

 The spathe retained its red- 

 dish and purplish colors in 

 fairly normal depth so far 

 as comparisons might be 

 made. In some instances 

 the hood showed a strong 

 epinastic growth by which it was recurved outwardly, and in nearly 

 all instances it was more or less nearly erected. (See Fig. 13.) 



Fig. 13. Arisaema triphylluj}i, grown in almost 

 absolute darkness. 



