TRE DRUPE-FRUITS . 135 



fruit, the black apricot shows close relationship to the plum, its 

 fruits being easily mistaken for dark-colored round plums. The 

 tree is hardier than that of the other apricots. The following 

 brief description distinguishes this species from the other two 

 apricots. Some authors consider it to be a hybrid. 



3. Prunus dasycarpa, Ehrh. Tree a little larger and more upright 

 than that of the common apricot or of the peach. Leaves long-ovate, thin, 

 dull green; margins finely serrate; petiole usually glandless. Flowers 

 large, showy; pedicel long. Fruit small, round, smooth, plum-like; stem 

 adhering, dark purple or nearly black; flesh soft, subacid; juicy, poor; 

 stone small, ovate, fuzzy, clinging to the flesh; kernel sweet. 



The Plum 



The tree and fruit of many species of Prunus are called 

 plums. Twelve or more wild species of plums grow in North 

 America, five of which have few or many cultivated varieties, 

 while five foreign species are under cultivation in this country. 

 The names and relationships of these ten plums are shown in 

 the following key : 



A. Flowers single or in twos. (Three in P. salicina.) 



Old World plums. 



B. Leaves drooping. 



C. Shoots and pedicels pubescent. 



D. Fruit large, more than 1 inch in diameter, 



variable in shape 1. P. domestica. 



DD. Fruits small, less than 1 inch in diameter, 

 oval or ovoid 2. P. insititia. 



CC. Shoots glabrous or soon becoming so, pedicels 

 glabrous. 



D. Flowers single; leaves hairy along the mid- 

 rib on the under side 3. P. cerasifera. 



DD. Flowers in threes; leaves glabrous 4. P. salicina. 



BB. Leaves upright, peach-like, glabrous, veins very 

 conspicuous, under side barbate at axils of veins; 

 separated from other plums by the large, flattened, 

 brick-red fruits 5. P. Simonii. 



AA. Flowers in clusters of 3 or more. American plums. 

 B. Leaves broad, mostly ovate or obovate. 

 C. Flowers white. 



