512 WHITE— STUDIES OF INHERITANCE IN PISUM. 



one of which will give purple dots in F^ as above and one of which 

 would only give maple as found by Bateson. 



Tschermak (86) secured in F^ from maple X colorless, brown 

 maple seed coat without purple specks. These F^'s gave in Fo, 

 52 maples: 17 dark brown self s : i ghost maple: 6 colorless. 



In F3, 

 Fo maples gave in one case all 4 classes ; in another case only 2 



classes — maples and colorless. 

 F. dark brozvns gave 6 brown : i colorless in one case ; in another 



7 browns : i colorless. 

 F2 ghost maple gave 9 ghost maple : 3 colorless. Ghost maples are 



hard to distinguish from whites, so Tschermak believes the 



F2 classes above approximate the ratio 9 maple : 3 brown : 3 



ghost maple : i colorless. 

 F2 ghost maple segregates X a pure colorless P. sativum race gave 



in Fi, 4 ghost maples : 2 colorless. 

 In F2, one of these ghost maples gave ghost maples which bred 

 true in F3 and F^, while another one ("spur" ghost maple) gave 2 

 like itself and 7 without mapling. One of the colorless F^ indi- 

 viduals gave 2 ghost maples and 6 colorless. In a similar cross, only 

 spurious ("spur") maples and colorless were obtained in F^, the 

 " spur " ghost maples giving 2 " spur " maples : 7 colorless in F,. 

 Tschermak believes these " spur " maples are due to the inactivity 

 of the determiner for mapling. Fruwirth and Tschermak both have 

 observed exceptional cases where mapling has appeared in the 

 descendants of non-mapled peas. 



In back-crosses of segregates from mapled ancestors. 



Brown X colorless never gave maple, 

 Brown X brown never gave maple. 



Certain peculiar ghost maples on plants with rose or pink flowers 

 X white-flowered ghost maples gave in F^ and F2 no maples. 



In reciprocal crosses between segregates of P. arv. X P. sat. in- 

 volving the maple pattern, Fo brown X ghost maple and reciprocal 

 [Table 22 (86)] gave in Fj, except in one case, always browns, the 

 exception giving 5 maple : 4 purple dotted non-maple. In Fo, in 

 some cases, the browns bred true, in others only brown and colorless 



