354 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



produces gametes G and g. Two gametes, Correns assumes, can 

 combine only if different, hence the four classes of progeny BG, 

 bG, Bg, and hg, judged by their fertility or sterility with the 

 pollen of the parents. 



It is obvious that this interpretation is based on several as- 

 sumptions quite secondary to the general doctrines of Mendelian 

 behavior, and quite limited and individual in application. 



The diploid constitution of the parents is represented by Bh 

 and Gg. This is the usual notation for the presence and absence 

 of an assumed factor. Here, however, "5" is the line stuff 

 derived from one immediate parent and "&" is quite another line 

 stuff from the other parent, but assumed to be inactive in the 

 plant B. The same is true of "G" and "g." In the matter of 

 notation, it would be more correct for his interpretation if Correns 

 represented these different substances by a different letter repre- 

 senting the composition assumed as Bx and Gy. 



Correns treats the offspring belonging to the classes Bg and bG 

 as if they also build only one active line stuff. The class BG, 

 however, builds two line stuffs, as both B and G are assumed to be 

 active. The assumption is that some plants may build two active 

 line stuffs, others only one. F'urthermore, the line stuffs b and g 

 (or X and z) assumed to be inactive in plants B and G are trans- 

 mitted to offspring, at least of the groups Bg and bG in the inactive 

 condition. It is not explained what line stuff the plants of the bg 

 class build, but as these plants are said to be self-sterile, either one 

 or both of the same line stuffs which were inactive in the parents 

 and which were inactive in the sister plants Bg and bG now be- 

 comes active or other active stuffs are operating (Correns even 

 considers the latter to be possible). 



Chance combinations between all gametes are, it is assumed, not 

 possible. No plants of the combination BB, GG, bb or gg are 

 assumed to appear as offspring of Bb or Gg. The plant Bb pro- 

 duces two kinds of jjollen, B and b, Init is scIf-stcrile to both; there- 

 fore, the active line stuff B of the pistils inhibits pollen tubes with 

 B and also b (which is another line stuff in inactive condition), or 

 the inactive stuff b is inhibiting the b pollen t ubes. It should be 

 noted, however, that later (p. 421) Correns classifies the progeny 

 of the cross bG X Bb in four classes, Bb, BG, bG, and bb, so that 

 here "6" eggs in the plant bG can be fertilized from b pollen or B 



