50 R. A. EMERSON 
to 5). That they were of three distinct genotypes was shown by the data 
recorded in table 16 (groups 4 to 6). The behavior of random intercrosses 
of the same green plants is now to be considered. The data are given in 
table 18. 
The green plants that served as parents of the crosses listed in group 
6 of table 16, it was decided, must have been aabb pl pl. When such 
plants are crossed with green plants of any of the other genotypes, nothing 
but green plants should result. A single cross of one of these greens with 
a green of the constitution aa B b pl pl (table 16, group 4) gave 23 green 
plants (table 18, group 1) as expected. Another cross of one of these 
greens with a green of the genotype aabb Pl pl (table 16, group 5) gave 
22 green plants (table 18, group 2). Crosses of green plants belonging 
to like genotypes should, of course, give only green plants. Three crosses 
of plants shown to be aa B b pl pl (table 16, group 4) gave 72 green plants 
(table 18, group 3). A single cross between plants shown to be aab 
b Pl pl (table 16, group 5) gave 24 green plants (table 18, group 4). Five 
crosses of plants of genotype aabbplpl with plants of genotype 
aabb Plpl gave a total of 40 brown and 105 green plants (table 18, 
group 5). Here a 1:3 ratio of brown to green is to be expected. The 
theoretical numbers are therefore 36 and 109, respectively, and the devia- 
tion is 4.0 + 3.5. The important fact here is that all these intercrosses of 
greens gave the color types expected on the basis of the results of crosses 
of the same individual green plants with dilute sun reds. The writer 
deems himself fortunate in having been able to obtain results approximat- 
ing so closely a complete demonstration of the several genotypes of 
green, since the selfing, the crossing with dilute sun reds, and the inter- 
crossing of greens, were made at the same time, with the green plants 
chosen wholly at random. 
~ Brown V «x green VIc.— When brown plants are crossed with green 
plants of type VIc, the F, plants are brown, and browns and greens alone 
appear in F,. Since brown is supposed to be a B Pl and type Vie green 
ab pl, the F2 progenies should exhibit 9:7 ratios. Eleven F,: pregenies 
are listed in table 19 (page 135), with a total of 317 brown and 223 green 
plants. The theoretical numbers are 304 and 236, respectively, showing 
a deviation of 13+7.8. There is more than one chance in four that such _ 
a deviation is due to errors of random sampling, P equaling 0.27. 
