G. P. HECTOR 163 
I. Aand B. Asegregates3: 1,B9: 7. If A and Bare due to separate 
factors, segregating independently, we should get— 
BO Sinn la 
Broa 7b 
2A Bees 9caBeZieAb' Fab 
Actually observed .. 1,646 : 0 : 552 : 818 (4 families of 3,016 
plants) 
The combination of “ green leaf-sheath, internode, apiculus, and stigma ” 
(a) with “ coloured ligule ” (B) does not occur. 
This again can be brought about if system A is due to a single 
factor, and system B to the same factor, together with a second 
factor interacting with the factor responsible for A in such a way that 
the presence of both is necessary for the production of colour. Thus again 
one factor is common to both, or the two factors must be completely 
linked. We thus get-- 
12A 4a 
eee 7o—_—__ es 
AB : Ab aB : ab 
9 3: 33 : a 
ee 
9B 3 Tb 
or wre 9AB : 3Ab : OaB: 4 ab 
Observed -. 1,646 es 3) : 0 : 818 (4 families of 3,016 
plants) 
Expect sete G9G%5 : 565:5)": 0 : 754 
il. A and C. A segregates 3: 1, C9: 7. This case is exactly com- 
parable to the former— 
1ZA 4a 
VS — 
AC : Ac aC ac 
9 3 2 3 
a 
9,C 7¢ 
or = OAC sia 'S, Aco: 0 aC: 4 ac 
Observed .. 1,647 ; 551 : 0 : 818 (4 families of 3,016 
plants) 
Expect se (696-5) esst000-Obee- Omees, , 754. 
The combination of “ green leaf-sheath, internode, apiculus and stigma ”’ 
(a) with “ coloured outer glumes ”’ (C) does not occur. 
