234. 



Gates. 



basal branches. These exceptionally long basal branches (see fig. 14) 

 invariably come into bloom before the main stem. In the presence 

 of such long branches at the base, the F^ differed decidedly from 

 either parent. The reciprocal cross showed a different habit, many 

 of the rosettes sending out a very long side shoot instead of a central 

 stem. This not infrequently happens also in rubricalyx and its rela- 

 tives, and presumably occurs as a response to some unknown physi- 

 ological conditions. There is apparently no tendency for the con- 

 dition to be inherited. 



Summing up the results of the F,, we may say (i) that the reci- 

 procals are closely similar except that grandiflora x rubricalyx (a) 

 has larger rosettes, (b) is more strongly biennial and later in deve- 

 lopment, (c) differs in habit. (2) The reciprocals are intermediate 

 between the parents, though possibly somewhat nearer rubricalyx than 

 grandiflora. (3) They were uniform in both cases, except in regard 

 to the one unit-character pair (Rr ) in which splitting in approximately 

 a I : I ratio occurred. 



E. 1. 0. grandiflora x 0. mut. rubricalyx and its reciprocal. Fg. 



We have already seen that in the F^ of these hybrids the characters 

 of the parents are perfectly blended and intermediate, with the single 

 exception of the unit character Rr. In the place of this uniform 

 blended condition, we have in F2 a complete series of intermediate 

 forms stretching all the way from one parent to the other as regards 

 nearly every character. Since all conditions of the various characters 

 are combined with each other in different individuals, the result is an 

 almost hopelessly confused series of forms. But before turning to 

 the intricate array of blended and partially blended conditions shown 

 by the numerous characters which differentiate the species, let us 

 consider first the relatively simple behaviour of the two unit-characters 

 R and t in the Fg. Even the inheritance of the simple unit-character 

 R is sufficiently complex when minutely studied. 



Last year I grew a total of 2794 plants in which the inheritance 

 of R was studied. These cultures are enumerated in table II. From 

 this table it will be seen that in addition to the F2 from the original 

 crosses, I have crossed both the Fj generations back with both parents, 

 and have also crossed the Fg generations reciprocally with each other. 



We may now consider the inheritance of the red character, R, 

 and the dwarf character, t, in detail. The following table (III) shows 

 the proportion of R and r plants in each family of the Fo. 



