No. 579] 



MUTATION EN MASSE 



131 



strain there were 99 plants of f. typica and one mutation 

 of a quite different type from either mut. semialta or 

 mut. debilis. The original F 3 culture had consisted of 

 26 plants, including two of f. typica, 16 of mut. semialta 



and eight of mut. debilis. In the supplementary culture 

 of 53 sister-plants, grown in 1914, there were 27 plants 

 of f. typica, 16 of mut. semialta and ten of mut. debilis. 



