INHERITED SEED-CHARACTERS 53 



embryo is roughly comparable to the seed : the 

 womb is a part of the mother, the embryo is the 

 next generation. The seed-coat is a part of the 

 parent-plant, the embryo with its two cotyledons 

 is the next generation. 



Mendel experimented with two pairs of 

 characters of these cotyledons : one pair related 

 to their colour, which was either yellow or green ; 

 the other to their shape, which was either round 

 or wrinkled. Let us consider the colour first. 



In the title to this chapter I have spoken of its 

 contents as being concerned with the characters 

 of " the seed." But, now that I have explained 

 that a seed is a composite structure, i.e. that 

 the seed-coat is a part of the parent plant, 

 and that everything inside this seed-coat is the 

 embryo of the next generation, it is necessary 

 when we speak of the characters of '' the seed " 

 to make it perfectly clear whether we are referring 

 to the seed-coat which belongs to one generation 

 or to the cotyledons which belong to the next. 

 Let it be clearly understood, therefore, that the 

 character with which we are now dealing is the 

 colour of the cotyledons, and not of the seed-coat. 



Mendel crossed a plant the first two leaves or 

 cotyledons of which were yellow, with a plant 

 the cotyledons of which were green. The result 

 was a plant the cotyledons oi: first two leaves of 

 which were yellow. 



This description of the cross made by Mendel 

 may sound unnecessarily explicit. But it is not so. 



