256 



CAUSES OF VARIATION 



GROWTH IN MILLIMETERS OF THE PLUMULES AND THE RADICLES OF SEED- 

 LINGS GROWN UNDER DIFFERENT TEMPERATURES FOR 48 HOURS (Sachs) 



MAXIMA, MINIMA, AND OPTIMA FOR VARIOUS SPECIES ARRANGED 

 ACCORDING TO THE OPTIMA 2 



1 Growth during 96 hours. 



2 C. B. Davenport, Experimental Morphology, Part II, p. 454. 

 Radicle. 4 Plumule. 



