PLANT CoLors IN MaIzE 69 
A type of dilute sun red with stronger husk pigmentation than ordinary 
dilute sun red shows was crossed with an ordinary dilute purple. Leaf 
type also was involved in the cross. The F, plants were dilute purples 
with somewhat more pigment in the husks of young ears than is usual 
with that type. A single progeny, grown from an F, backcrossed with 
liguleless dilute sun red of a light type, consisted of 25 dilute purples and 
18 dilute sun reds. Each of these classes was sorted with some difficulty 
into light and more strongly colored subclasses, in accordance with the 
amount of color on the husks of the young ears. Of the more strongly 
pigmented dilute sun reds 4 had normal and 6 had liguleless leaves, while of 
the lighter dilute sun reds 6 had normal and 2 had liguleless leaves. Of the 
more strongly colored dilute purples 4 had normal and 13 had liguleless leaves, 
while of the lighter ones 4 had normal and 4 had liguleless leaves. While 
these numbers are small and the behavior was somewhat irregular, it is 
perhaps noteworthy that the factor pair differentiating the lighter from 
the more strongly colored plants, of both the dilute sun red and the dilute 
purple classes, exhibited an apparent linkage with Lg lg of a value not 
far from that observed between Lglg and Bb, BB’, and BY b. The 
observed percentages of crossing-over were 32.0 for the dilute purples, 
33.3 for the dilute sun reds, and 32.6 for the entire lot. This evidence, 
slight as it is, plainly suggests a fourth member, b*, of the B series of 
allelomorphs, which may be stated tentatively as B, BY, b’, b. 
Relation of weak purple Ib to purple Ia, dilute purple IIIa, and weak sun 
red IIb 
By methods similar in the main to those outlined above, Dr. E. G. 
Anderson has been able to show that weak purple is differentiated from 
purple on the one hand and from dilute purple on the other by the same 
factor, B”, that differentiates weak sun red from sun red and from dilute 
sun red. At the time when Dr. Anderson undertook to determine the 
genetic relations of weak purple, nothing was known of the relation of 
weak sun red to sun red and dilute sun red as presented above. Further- 
more, there was no indication as to whether weak purple was differentiated 
from purple and dilute purple by an allelomorph of B 6 or of Pl pl, or by 
some distinct factor pair that might modify the ordinary result of the 
interaction of the pairs Aa, Bb, and Pl pl then known to be concerned 
in the production of plant colors. The evidence to be presented here 
