536 WHITE— STUDIES OF INHERITANCE IN PISUM. 



cotyledons and of Bateson). Tschermak, so far as the writer can 

 discover, makes no mention of the resuUs of this cross as excep- 

 tional. 



Round smooth, colored flowers X wrinkled, white flowers in F^ 

 (of cotyledons) is indent, which in F, of cotyledons (F^ of seed 

 coat) give approximately 3 dimpled : i wrinkled (54). According 

 to Lock, dimpled and wrinkled seeds are very hard to distinguish, 

 as of course true wrinkling occurs in colored seed coats. 



Indent X indent (colored flowers always) gives in F^ and later 

 generations always indent and colored flowers. 



Indent X wrinkled, white flowers in F^ gives indent. Reciprocal 

 in Fj (of cotyledons) gives round smooth seeds. In Fo (F^ of seed 

 coats) of both crosses, indents to wrinkles appear in a ratio of 3 : i 

 and the plants all have colored flowers. 



The wrinkled seeds when sown give 3 wrinkled with colored 

 flowers : i wrinkled with white flowers. The indent seeds if sown 

 [(F, of seed coats) F, of cotyledons] likewise give rise to 3 colored- 

 flowered plants : i white-flowered plant. The colored-flowered 

 plants have either all indent seeds or indent and wrinkled seeds in 

 the ratio of 3:1. The white-flowered plants have either all round 

 seeds or 3 round : i wrinkled. 



Indent X wrinkled, colored flowers. No data. 



Wrinkled, zvhite flowers X wrinkled, white flowers always gives 

 wrinkled seeds and white-flowered progeny. 



Wrinkled, colored flowers X itself. No data. 



Back crosses (81) of various combinations involving indent an- 

 cestry gave no exceptional results, as viewed from the interpreta- 

 tion given for all the crossing data. 



Interpretation. 

 The preceding data concern two sets of characters — (i) round 

 smooth cotyledons of low water absorptive capacity with simple, 

 long starch grains and angular wrinkled cotyledons of high water 

 absorptive capacity with radially split (compound), round starch 

 grains; (2) indent and non-indent seeds. In the first set, round 

 smooth and the characters associated with it are to be regarded as 

 the expressions of a factor R, in the absence of which the cotyledons 



