182 THE EVOLUTION OP OUR NATIVE FRUITS 



other environments which cause plants to assume 

 new forms. If, therefore, we cannot delimit the 

 species of Prunus to our satisfaction, we shall, never- 

 theless, find them to be a most suggestive study when 

 we attempt to trace the evolution of our native fruits. 

 The wild plum of the North is known to botanists 

 as Prunus Americana (Fig. 25). It was first de- 

 scribed by Humphrey Marshall in his "Arbustxum 

 Americanum," in 1785. Marshall's complete account 

 is as follows : 



"Prunus Americana. Large Yellow Sweet Plumb. 

 This generally rises to the height of 12 or 15 feet, 

 spreading into many stiif branches. The leaves are 

 oblong, oval, acute pointed, sharply sawed on their 

 edges and much veined. The flowers generally come 

 out very thick round the branches, often upon thick 

 short spurs ; and are succeeded by large oval fruit 

 with a sweet succulent pulp. We have a great variety 

 of these, growing naturally in a good moist soil, with 

 reddish and yellowish fruit, but differing much in 

 size, taste and consistence." 



The species has a wide range. It grows in thickets 

 and woods from Newfoundland to Colorado, Florida 

 and Texas, and northern Mexico. It is commonly a 

 small low-headed tree, or sometimes only a large bush, 

 making a thick and usually thorny top. It bears a 

 firm, meaty, usually compressed, dull -colored late 

 fruit, with thick and usually very tough, glaucous 

 skin, and large more or less flattened stone, which is 

 often nearly or quite free ; and the leaves are large 

 obovate, thick, veiny, jagged and dull. The fruits of 

 wild forms of Prunus Americana vary widely in sea- 

 son, size, shape, flavor, and character of stone. Trees 



