64 BREEDING 



If the green seeds containing the cotyledons of 

 the second hybrid generation had been sown they 

 would produce greens only ; but as I did not test 

 the true breeding of these so-called " extracted " 

 greens in this particular experiment, the fact that 

 they breed true is not illustrated in the Table on 

 p. 62. 



Fig. 20 shows the distribution of yellow and 

 green seeds borne by Plant No. 12, which was 

 selected at random. Yellow seeds are indicated 

 by • and green ones by o. It will be seen that 

 no order can be detected in the distribution of the 

 seeds of the two colours. 



This diagram brings home to one's mind the fact 

 that the colours of the seeds of a plant, when we 

 mean the colours of the contained cotyledons, are 

 the colours of the offspring (or, rather, of the first 

 two leaves of the offspring) of that plant ; whilst 

 the colour of the seed-coats of the seeds borne by a 

 plant is the colour of a part of the plant itself, just 

 as the colour of the pods is, or the colour of the 

 stem. That is why the colours of the seed-coats 

 (whether grey or white) of the seeds borne by a 

 plant are always the same {see Fig. 11 or 12), and why 

 the colours of the cotyledons of the seeds- borne by 

 a plant need not be always the same (see Plate I., 

 facing p. 58). And the apparent paradox that " the 

 seed " presents a pair of characters (grey and white) 

 which are the latest to appear in the life history of 

 the plant, and another pair (yellow and green), which 

 are the earliest to appear, is explained by the fact that 



