514 WHITE— STUDIES OF INHERITANCE IN PISUM. 



In F5, 6 such crosses gave : 9 maples : 14 non-mapled, 

 28 such crosses gave all maples (over 75), 

 27 such crosses gave all non-maples (over 75), 



Colorless X purple is only mentioned by Vilmorin (90), in which 

 purple is said to be dominant. 



Gray X gray, according to the data of Tschermak and Lock, may 

 give only gray in F^, F^ and succeeding generations. 



Gray X gray with purple dots, excluding exceptional cases such 

 as are mentioned under colorless X gray with purple dots, always 

 gives gray with purple dots in F^ and grays with and without purple 

 dots in F, in an approximate ratio of 3:1. The purple-dot pattern 

 in the F^ of both these crosses and those of colorless X gray with 

 purple dots is much intensified, and in both cases the stippling pat- 

 tern may vary so as to produce peas with wholly purple seed coats. 

 These are found sometimes in pods containing some purple and 

 some purple-specked seeds. In other cases a whole pod of a plant 

 may contain all purple seed coat peas. Occasionally a seed may be 

 half purple and half gray or maple. Fo plants from seeds with 

 purple seed coats do not give results differing from the purple 

 stipple seeds. Bateson ( i ) thinks such purples are not present in 

 pure stocks of purple-specked seed coat races, and that crossing in 

 some manner promotes their appearance (see Darwin, Bateson, 

 Lock, Tschermak, Fruwirth for further data on this subject). 

 Fruwirth (34) experimented with the variety Blauhiilsige, a purple- 

 podded race of peas, which had in respect to seed coat color, four 

 types of peas on the same plant, often mixed together in the same 

 pod. These were either pure yellowish green, yellowish green with 

 purple flecks or dots, purple with small greenish yellow flecks, and 

 self purples, in respect to seed coat color. These are evidently de- 

 grees of variation of the same character. As they occur in a pure 

 variety, Bateson's belief as to the effect of crossing as a stimulus 

 to such extreme variation is not supported. Observed also by Lock 

 on both pure and cross-bred strains (56). 



Gray X gray with maple marbling gives in F^ maple marbling, 

 which in Fo in simple crosses gives 3 maples : i gray. However, 

 such simple crosses are rarely to be had and the crosses usually in- 

 volve the purple-dotted pattern. 



