WHITE— STUDIES OF INHERITANCE IN PISUM. 517 



associated with white flowers. These various associations of the 

 characters just mentioned, in their inheritance are, so far as our 

 data go, absolutely without exception. 



From the foregoing array of facts one may gather that the 

 heredity of seed coat color is somewhat comphcated as compared 

 with that of other pea characters, but this is largely due to the ease 

 with which such characters can be studied and consequently the 

 amount of work that has been accomplished on them. 



Interpretation, 



From a Mendehan standpoint, the heredity of seed coat color 

 and pattern, as deduced from the foregoing mass of data, is com- 

 paratively simple. 



Brownish, grayish green or gray seed coat color may be repre- 

 sented by the factor Gc which is absolutely coupled with the factor 

 A for colored flowers. In the absence of Gc, seed coats are color- 

 less. The factor J acts upon Gc so as to produce dark chocolate 

 brown. It is independent of Gc or A and is carried by either 

 colored-flowered, gray seed coat varieties or white-flowered, color- 

 less seed coat varieties. In the latter, it remains without expression. 

 The orange tint or color is regarded by Tschermak (86) as due to 

 a factor H, which alters the gray color to orange-red or orange- 

 yellow. So far H has not been found in white-flowered races 

 though there is reason to suspect its presence there (see p. 511). 

 The factor U, which provisionally stands for self purple seed coats, 

 is also probably coupled with A, although there are very little data 

 on the subject. Varieties with colored flowers then, carrying only 

 the factor Gc, will have gray seed coats; if J is added, brown seed 

 coats; if both J and H are added still brown seed coats, but if J is 

 eliminated and only Gc and H are present, orange seed coats. If 

 the factor U for self purple is added to Gc, the seed coat is self 

 purple. No data are available as to other combinations of U. 



Purple spotting is represented by Tschermak (86) as due to two 

 factors, one coupled absolutely with A and Gc, the other independ- 

 ent, hence present in both white-flowered and colored-flowered 

 varieties. Lock (54, 55) represents similar results by one factor 

 operating only in the presence of the factor for gray seed coat color. 



