Studies of Teratological Phenomena. 117 



numerous maturing seed capsules. Under the latter conditions neither 

 the character fasciation (in floral expression) nor calycanthemy are 

 expressed typicalh'. This is especially true of the individuals of the 

 Aa and Bb categories. Table 25 gives the character of the individuals 

 of this F2 population, and enables one to note the fluctuation as 

 regards each class. I consider the individuals of the classes AABB, 

 AABb, AaBb, Aabb and aaBB to be the most accurately identified, and 

 those of aaBb and aabb as probably the most inaccurately placed, as 

 some of the former no doubt are AaBB and AaBb and some of the 

 latter also are AaBb. But all the discrepancies between the actual and 

 expected ratio cannot be accounted for by assuming preventable error 

 to be the cause. The classes aaBb and aabb especially are too high 

 to be explained in this manner, and in all counts the greatest dis- 

 crepancy occured in the class aabb. But the factor B was not causing 

 the distortion of the ratio, for in a population of 469 F2 individuals, 

 351 were abnormal (BB or Bb) and 118 normal (bb)^), a very close 

 approach to the expected ratio. The factor A was causing the trouble 

 as shown by the total number of abnormal (A A and Aa) to the total 

 normal (aa) segregates. An examination of the whole F2 population as 

 regards stem-fasciation gives an added basis for my statement. Table 25 

 gives the total fasciate- stemmed plants to those with normal stems, 

 the proportion being about IF to 8*5 N., whereas theory demands 

 3F:1N, and at least *119 (*1F:2FN:1N) plants fasciated enough 

 in this structure to be easily distinguished, and twice that number with 

 slightly altered stems. In making the observations, all plants showing 

 the least indication of monstrous alteration in stems were included in 

 the (F) class. 



It is very evident in this hybrid population, that too many aa and 

 not enough AA and Aa segregates were present to accord with theory, 

 A glance at the nature of the characters present additional to those 

 caused by factors A und B disclosed similar conditions to those found 

 in the 353 X 301 and 301 X 373 populations. The two grandparental 

 races differed by a large number of factors, and these were segregating. 

 Height, leaf character, branched and uubranched habit, normal leaf 

 number and numerous floral characters are a few of the more prominent, 

 and as a consequence of this great shuffling of factors, the 477 

 segregates presented striking dissimilarities. Hardly two of the whole 



') Note second count. 



