G. H. Shull 93 



thus: green with dark red, pink with bright red, red with gi-een. The 

 fine red specks often seen on the ovaries show a partially independent 

 series, being absent in (a), nunierons in (b) and scarce in (c). 



The distribution of the adult plants shows that the classification of 

 the rosettes into spotted and unspotted categories was not in this case 

 a natural grouping, as it was in the reciprocal rubricalyx-rubrinervis- 

 crosses, and this difference is doubtless due to the fact that my 

 0. Lamarckiana has moderately spotted rosettes while 0. rubrinervii 

 is unspotted, as sho%vn by Plates V and VI (bottom series in each). All 

 plants of groups (a) and (b) had spotted rosettes, and two-thirds of the 

 former were noticeably more strongly spotted than the rest of the 

 spotted plants. All the imspotted rosettes and most of the moderately 

 spotted ones developed into plants of type (c). It is thus seen that 

 although the pigmentation of the rosette is not in this hybrid com- 

 bination, as sharply diagnostic of the natural groups, the nature of the 

 association between the pigmentation of the rosette and that of the 

 adult organs is the same, in direction, in the ruhricalyx-Lumurckiana- 

 cross as in the rubricalyx-rubrineims-cross. Stated more generally, 

 there is a positive correlation between the red-pigmentation of the 

 rosette-leaves and that of the adult stems, and a corresponding negative 

 correlation between the red-pigmentation of the rosette and the red- 

 pigmentation of the buds. 



Oenothera Laiuarckiana x rubricalyx Fi. 

 Pedigree Nos. 118(10) x 11410(1) = 1235. 



Seeds of this cross produced 117 plants which were at one time 

 grouped provisionally into 36 Lamarckiana-Uke, 18 rubricalyx-like 

 and 37 rubrinervis-\ike, besides a considerable number of individual 

 aberrants. As these names proved later to be inappropriate it is 

 desirable to translate them for our present use into terms of their 

 pigment-characters. The " Lamurckiana-\ike" group and the " rubri- 

 cali/x-Vikc " gi-oup had red-spotted rosettes, and the " rubrinervis-Wke " 

 group had unspotted rosettes. Unfortunately, several of the divergent 

 rosettes which received individual description, were not noted with 

 reference to the presence or absence of red spots, and only 113 are now 

 classifiable on the basis of the red spotting of the rosette-leaves ; of 

 these, 64 were spotted and 49 unspotted. Most of the slightly aberrant 

 rosettes developed into adult plants not perceptibly divergent from 

 other plants which had not been noticeably aberrant in the rosette- 



