Selby: Studies in etiolation 



71 



oped than in the normal. These differences will be evident in the 

 illustrations (plate 5, figures 1 and 2). Referring to the analysis 

 it is observed that the increase in the thickness of the etiolated 

 stems has not been accompanied by any considerable increase of 

 solid matter and that the etiolated plant contains about 3 y 2 per 

 cent, more water than the normal. These results are in harmony 

 with those previously obtained by others. 



Figure C. Normal plant of Asclepias incarnata. 

 Figure D. Etiolated plant of Asclepias incarnata. 



Roots of Asclepias incarnata were likewise collected at Woos- 

 ter, and plants grown from them in the etiolating chamber and the 

 propagating house of the New York Botanical Garden. The 

 etiolated plants of this milkweed started to grow earlier than the 

 normal, and produced longer stems (figures C and D). These 

 developed as many as 13 or 14 internodes, with a length varying 

 between 5 and 12 cm. The lower axillary buds of the etiolated 



