228 Macfarlanc — Tlic Beach Plum, Viczued 



most of the types already described can be found in close 

 proximity, at all of the localities already named, from Cape 

 May Point in the South to Falmouth and Martha's Vineyard 

 in the North. This might lead us to suppose that in all these 

 centers agencies were at work, that so acted on some primi- 

 tive type or types, as to cause such to branch out into the 

 varieties described. 



Before discussing this further, it may be well to adduce 

 some evidence in favor of the ground already taken that No. 

 I of our table or some closely related form represents a 

 primitive ancestral type that has come down to us, and has 

 been the starting point, in all probability in the past, of most 

 if not all of the varieties described. In nearly all the natural 

 orders of plants that contain succulent fruited genera, the 

 species that have the largest and richest fruit pulp are the 

 most highly evolved, since seed dispersion by animals is 

 increasingly aided by increased succulence. We can likewise 

 accept it as proven that the primitive fruits were dry and that 

 increasing succulence indicates advancing specialization. But 

 as with flowers, so with fruits. The most primitive are of a 

 green or semi-green color. Type I would conform to such a 

 requirement better than any of the others. The large amount 

 of tannin in some varieties, particularly in specimen I, though 

 it might prove to be protective against certain hurtful agents, 

 seems rather to indicate a primitive condition, derived from a 

 dry fruited type in which tannin is a frequent constituent. 

 The practical disappearance of it from the finer fruits of the 

 Beach Plum, and the abundance in them of sugar, favor the 

 view that the varieties most rich in tannin are the most 

 primitive forms. 



As regards the lateness of ripening of No I, and a few 

 related examples, this does not seem to be a matter of special 

 importance. It is well known that several late-maturing 

 apples and pears rank among the choicest, sufficient proof this 



