WHITE— STUDIES OF INHERITANCE IN PISUM. 537 



are angular, wrinkled, etc. The partial dominance of shape and 

 constitution of the simple long starch grains in F^ is perhaps modi- 

 fied by other factors not yet determined or due to the presence of 

 R in simplex condition. It is very evident from the diverse results 

 of Darbishire and Kappert as regards F^ starch characters that 

 dominance of the simple or the " compound " type is inhibited in one 

 case at least. 



So far as is known, the factor R is inherited independently of 

 all other Pisum factors excepting the factor for tendrils (Tl) with 

 which it is partially coupled. Interpreted as above, round-seeded 

 varieties of peas have the formula RR while wrinkled varieties 

 have the formula rr. 



Indenting in peas, as interpreted by Tschermak, Bateson, Lock 

 and others, is due to two or three ( ?) pairs of factors, one of which 

 is the pigment-producing factor A, which gives rise to pink flowers 

 and gray seed coats. Indent peas only occur on plants with colored 

 flowers, all of which have the factor A. A may be substituted for 

 Tschermak's factor L^ since L^ and A are akvays associated. Taken 

 thus the real indenting factor may be designated as Lo, in the ab- 

 sence of which in plants with colored flowers, the seeds are non- 

 indent. When A and L, are both present the flowers and seed coats 

 are colored and the seeds are indent. When A is absent but Lg 

 present, the flowers and seed coats are white or colorless and the 

 seeds non-indent. 



Thus all varieties of peas so far experimented with, having col- 

 ored flowers, colored seed coats and indent seeds, may be represented 

 by the formula AAL.Lo, those with colored flowers, colored seed 

 coats and non-indent seeds by AALL and those with white flowers, 

 colorless seed coats and non-indent seeds by aaLoLo, because the 

 latter in crosses with colored-flowered, non-indent types give in F^ 

 (of seed coats) all indent peas. 



Considering the two sets of characters together, the factor A is 

 found to mask the factor R or is epistatic, to use Bateson's term. 

 The absence of R, i. e., r or wrinkledness, on the other hand is epi- 

 static to A. The varieties of peas thus far genetically studied on the 

 basis of the interpretation given above, fall into four classes which are 



