INHERITED SEED-GHARACTERS 59 



And in the two pods are seen the cotyledons of the 

 second hybrid generation ; the skins of the two peas 

 to the extreme left of the upper pod have been removed 

 in order to show the yellow and the green of the 

 cotyledons of the second hybrid generation in juxta- 

 position to one another. In the two pods shown there 

 are eleven yellow and four green — as close an 

 approximation to a ratio of three yellow to one green 

 as can obtain amongst fifteen seeds. 



The colours of " the seeds " borne on a plant 

 of the first hybrid generation which has been pro- 

 duced by a cross between a yellow-seeded and green- 

 seeded pea are simply the colours of the first two 

 " leaves " or cotyledons of the plants of the second 

 hybrid generation. 



I have endeavoured to illustrate this — and, 

 incidentally also, the general fact with which the 

 reader is now familiar, that the colours of " the 

 seeds " (whether yellow or green), borne by a plant, 

 are the colours of the first two leaves of its children — 

 by taking a photograph, reproduced in Fig. 18, of a 

 pod containing the cotyledons of the second hybrid 

 generation ; then sowing the seeds in a row in the 

 order in which they were in the pod, and photo- 

 graphing the seedlings thus raised (Fig. 19). This 

 illustration shows, I think, sufficiently clearly that 

 the characters, yellowness and greenness, of cotyledons 

 are characters which appear at a very early stage in 

 the development of the plant, so early in fact that 

 they can be seen in the seed (if the seed-coat be 

 transparent) before they are sown to produce the 



