58 R. A. EMERson 
F; lot, two (group 4) gave only purples and sun reds, and one (group 5) 
gave only purples and dilute purples. 
The twenty .F, and F3; purples tested, therefore, were distributed with 
respect to the four kinds of behavior in the relation 7:6:6:1, in contrast 
to the calculated distribution of approximately 8.9:4.4:4.4:2.2. There is 
more than an even chance that such a difference may be due to errors 
of random sampling, P equaling 0.53. On the whole, therefore, the F» 
purples of this cross behaved in later generations as was expected of 
them. 
F, sun red plants of the cross purple x dilute sun red showed two types 
of behavior in F; (table 31, group 1). Three F2’s bred true, with 53 sun 
red plants in F;. Four gave a total of 70 sun red and 24 dilute sun red 
plants. Where an expected ratio of one true breeding to two segregating 
progenies was expected, the observed relation of three to four is not a bad fit. 
F, dilute purples also showed the two types of behavior expected in 
F; (group 2, table 31). Three bred true, with a total of 97 dilute purple 
plants, and six gave a total of 217 dilute purple and 86 dilute sun red 
plants. The 1:2 ratio was therefore exactly realized. 
Three F, dilute sun reds bred true in F; (group 8) as was expected 
of them, producing a total of 72 dilute sun red plants. 
Numerous F; plants of the several color types of the cross under con- 
sideration here were tested by Fy and F; progenies, with results wholly 
consistent with expectation. It is deemed unnecessary to give the records 
of these later generations in detail. 
Evidence from aleurone-color and linkage relations 
The evidence presented up to this point in support of the three- Factee 
hypothesis, involving Aa, Bb, Pl pl, has had to do ,with the behavior 
of the several F, color types in later generations and in intercrosses. 
There remain to be discussed some bits of evidence which, while less direct, 
are perhaps no less trustworthy. This evidence deals with (1) the relation 
of aleurone color to plant-color types, (2) the linkage of certain plant-color 
types with endosperm color, and (8) the linkage of other color types 
with the liguleless leaf. 
Relation of aleurone color to plant color.— Of the alm olor factors 
considered in this section of the paper, the pair A a is concerned also 
in the development of aleurone color. It has been shown by the writer 
