3. In a cross between a line with coloured aleurone and rr lines, four alleles of R could be distinguished by their different effects on aleurone colour. Otherwise the plants were of the constitution AA CC bb Pl Pl. At least one of the R alleles involved seems to be a cherry allele. Two alleles were the normals, at present designated R and r. A third may be identical with the allele recently discovered by Rhoades, and designated here r'. The fourth is a very weak, dominant called R'. The four heterozygotes when selfed gave

Rr25% colourless
Rr'35% "
R'r50% "
R'r'mostly 66%, in one case 75% colourless

It seems possible to obtain colourless R' homozygotes by selection of modifiers. The ratios 63:1 after selfing and 1:7 after backcrossing seem to indicate the presence of at least three complementary recessive modifiers.