Strawberries. 9 1 



tively easy to produce any one single change unac- 

 companied by others ; but it is comparatively difficult 

 to produce the whole set of changes whereby the two 

 strawberries differ alike from all their congeners. So, 

 if we are going to make a niew genus, Fragaria, with 

 a Latin name at all, we ought to make it include both 

 the true strawberry and the barren strawberry, while 

 we relegate to the genus Potentilla all the other less 

 closely related kinds. But perhaps we shall do better 

 if we lump them all together in a single genus, con- 

 sidering that, after all, the barren strawberry does not 

 differ more from the remainder of the potentillas than 

 many of these differ from one another among them- 

 selves. 



And now, how did the edible strawberry get 

 developed from its barren ally ? Well, if we take the 

 fruit of any potentilla, we shall find that it consists of 

 several small, dry, one-seeded nuts, so tiny that they 

 look themselves like seeds, crowded on a thick recep- 

 tacle or flower stalk, without any signs of redness or 

 succulence. In some potentillas, however, as the fruit 

 ripens, this receptacle becomes a little spongy, some- 

 thing like the hull of a raspberry, only without its pulpy 

 character. It is a common tendency of fruits to de- 

 velop such pulpiness, and sometimes they do so quite 

 suddenly by apparently spontaneous variation, as when 



