78 GENETICS IN RELATION TO AGRICULTURE 
2. The Difference in Color of the Cotyledons.—The cotyledons of the 
ripe seeds are either pale yellow, bright yellow, or orange-colored, or 
they possess a more or less intense green tint. 
3. The Difference in Color of the Seed Coat.—This is either white, with 
which character white flowers are constantly correlated; or it is gray, 
gray-brown, leather brown, with or without violet spotting, in which 
case the color of the standards is violet, that of the wings purple, and 
the stem at the base of the leaves is of a reddish tint. 
4. The Difference in Form of the Ripe Pods.—These are either 
simply inflated, not contracted in places; or they are deeply constricted 
between the seeds and more or less wrinkled. 
5. The Difference in Color of the Unripe Pods.—They are either light 
to dark green, or vividly yellow, in which coloring the stalks, leaf veins, 
and calyx participate. 
6. The Difference in Position of the Flowers.—They are either axillary, 
that is distributed along the main stem; or they are terminal, that is 
bunched at the top of the stem and arranged almost in a false umbel; 
in this case the upper part of the stem is more or less widened in cross- 
section. 
7. The Difference in Length of the Stem.—The length of the stem is 
very various in some forms; it is, however, a constant character for 
each, in so far that healthy plants, grown in the same soil, are only sub- 
ject to unimportant variations. In the experiments a long axis of 6 to7 
feet was always crossed with a short one of 34 to 114 feet. 
The results of segregation in F’, in these seven series of experiments 
have been summarized from Mendel’s paper in Table VII: 
Tasie VII.—SumMmary oF MENDEL’s EXPERIMENTS WITH PEAS 
No. Character contrast No. in F2 Dominants Recessives | Ratio per 4 
1 Form of seed.......... 7,324 5,474 1,850 2.99:1.01 
2 | Color of cotyledons..... 8,023 6,022 2,001 3.00 :1.00 
3 | Color of seed coats..... 929 705 224 3.04 :0.96 
4, | MRorma: Of MOG ye... eect 1,181 882 299 | 2.99:1.01 
5 | Color of pod........... 580 428 152) | 2.95:1.05 
6 | Position of flowers...... 858 651 207 3.03 :0.97 
7 | Length of stem....... é 1,064 787 277 2.92 :1.08 
AOE Seat tn at ee 19,959 14,949 5,010 = |2.996 :1.004 
i} 
Mendel observed no transitional forms in these experiments so that 
the ratios he obtained are based entirely on unprejudiced observations. 
The ratios in no case differ significantly from the ideal 3:1 ratio. Several 
investigations have furnished confirmatory evidence as to the correctness 
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