VARIATION 



313 



following average numbers of stamens: (i) 9.68, (2) 8.45, (3) 6.54, 

 (4) 5.05, (5) 9.47, (6) 7.33. Finally, Klebs subjected similar plants 

 from white, red, and blue light to chemical analysis in order to secure 

 further evidence of the physiological effects of light of different wave 



FIG. 51. Sedum spectdbile. The three shoots (taken from a single plant) 

 were planted in small pots on March 12, 1904, and placed in different greenhouses, 

 7, in blue light; II, in mixed white light; III, in red light. Photographed on 

 September 30, 1914. (From Babcock and Clausen, after Klebs.) 



lengths. Table I shows the composition of the leaves in three plants 

 like those shown in Fig. 5 r . They were in their respective greenhouses 

 from June 6 to September 7. The percentages shown are per 100 g. 

 of dry substance. 



In comparing these percentages it should be remembered that the 

 plant in white light produced 1324 flower buds and the plant in red 

 light 405, while the plant in blue light produced none. This explains 

 the higher percentage of ash, nitrogen and protein in the last. On 

 the other hand, the amounts of starch and sugar found in the plant 

 from white light are decidedly larger than the one from blue light. 



