MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 293 



an intensity which reduced photosynthesis to one-third the average 

 rate in sunlight also resulted in the development of leaves which did 

 not reach the average normal size, while the branches on which they 

 were borne were more slender, attenuated and with internodes longer 

 than the normal. In both instances the amount of chlorophyl pres- 

 ent seemed to be greater than usual. The more prominent features 



A 



Fig. 172. Lupinus albns. A, partial transverse section of normal leaflet. 6', par- 

 tial transverse section of leaflet grown in an atmosphere lacking carbon dioxide. 

 After Teodoresco. 



of the development of plants grown under such weak constant illu- 

 mination are more nearly like those of specimens grown under dis- 

 continuous diffuse light, both as to the size of the leaf and the devel- 

 opment of the stem. Whatever differences are to be seen may be 

 attributed to the fact that in the case of the plants grown under con- 

 stant illumination the stimulating action of light was never absent, 

 and to the fact that the total amount of material resulting from the 

 photosynthetic processes must have been much greater than in plants 

 which were exposed only a portion of the day to diffuse light. It is 

 to be said that certain features of Bonnier's results need further in- 

 vestigation before any generalizations might be safely made con- 

 cerning them. Thus for instance, it is not clear why plants grown 

 in discontinuous electrical illumination should more nearly resemble 

 normally grown plants than etiolated ones, which those grown in 

 continuous illumination resemble, a result that is confirmed by 

 Bailey, Rane and Corbett. Several important conclusions might 

 be drawn from a superficial inspection of the results in ques- 

 tion. The exaggerated length of plants grown under conditions 



