184 THE EVOLUTION OF OUR' NATIVE FEUITS 



in the same clump often vary two weeks iii season of 

 ripening of fruit, which may vary from dull, deep red 

 to yellow, and from the size of a small cherry to that 

 of a common garden plum. It should be said, how- 

 ever, that there is no true clear yellow fruit in this 

 species. The yellow of P. Americana is always a 

 more or less ill -denned under- color, over which are 

 laid blotches of red. The fruits are commonly marked 

 with a distinct suture. All the varieties have a light 

 purple bloom. The Texan form of Primus Americana, 

 known locally as the Hog plum, appears to differ some- 

 what from the northern forms, but there seems to be no 

 reason to regard it as a distinct species. The Prunus 

 Texana of Scheele is Prunus Americana, as shown by 

 an authentic specimen in the Engelrnann herbarium at 

 St. Louis. The Texan type is not in general culti- 

 vation, however, and need not be further discussed 

 here. It is in the northern prairie states, as I have 

 said, that this species reaches its greatest excellence 

 in fruit-bearing. All the horticultural varieties of 

 merit, so far as I know, have originated in northern 

 Illinois, Wisconsin, Minnesota, Iowa, South Dakota, 

 Nebraska and Kansas, with one or two unimportant 

 exceptions in Texas. 



Some botanists suppose that this northern plum 

 really comprises more than one natural species. Pro- 

 fessor Sargent is of the opinion that the Prunus 

 nigra of Aiton should be revived to designate those 

 forms which are characterized by very flat and smooth 

 stones, very broad leaves, glandular leaf -stalks and 

 calyx lobes, and large flowers ; and he inserts a plate 

 and description of what he conceives to be this 

 species in his noble "Silva of North America." My 



