136 



ROSACE^E. 



Prunus Virginiana Linne (Primus Canadensis Marshall, Prunus 

 serotina Poir, Cerasus Virginiana Loiseleur, Cerasus serotina Hooker). 

 Choke-Cherry. 



Description. Petals roundish. Fruit about the size of a pea, dark red 

 when fully ripe, and of an extremely astringent taste. 



A shrub or small tree, with a grayish bark. Leaves thin and mem- 

 branous, 2 to 3 inches long, broadly oval, oblong or ovate, abruptly 



pointed, very sharply and often doubly 

 serrate. Flowers in loose, short ra- 

 cemes terminating the branches, ap- 

 pearing in May after the leaves are 

 considerably developed. 



Habitat. From Canada to the Gulf 

 of Mexico and westward ; everywhere 

 common. 



Part used. The bark of Prunus 

 serotina Ehrhart official name, Pru- 

 nus Virginiana wild cherry United 

 States Pharmacopeia. The bark of the 

 other species is said to be fully as ef- 

 ficient. As will be seen by reference 

 to the synonomy of the two species, 

 there has been great confusion among 

 botanists in their nomenclature ; 

 hence the wild cherry of the Pharma- 

 copoeia bears as its official name the 

 proper, and at present generally ac- 

 cepted, title belonging to choke- 

 cherry. 



Constituents. Wild cherry bark 

 contains tannic and gallic acids, resin, 

 starch, and other common vegetable 

 principles, and by distillation yields 

 a peculiar volatile oil resembling the 

 volatile oil of bitter almonds, con- 

 taining hydrocyanic acid. The acid does not pre-exist in the bark, but 

 is formed by the action of a proteid upon amyydalin, an amorphous 

 or crystalline principle present in all plants of this sub-order. Amyg- 

 tlalin is not poisonous itself, nor is the proteid substance. Moreover, 

 the latter is coagulated by heat and thus rendered inert ; hence in 

 order to obtain hydrocyanic acid from wild cherry, the bark must first be 

 subjected to the action of cold water. A peculiar bitter principle is also 

 present in wild cherry to which certain of the medicinal properties of the 

 bark are due. 



FIG. 122. Prunns serotina Ehrhart (Cerasu 

 (erotitia) 



