CHAPTER XXXIX: THE PLUMS AND THE 

 CHERRIES 



Family Rosace.^ 



Genus PRUNUS, B. & H. 



Trees with bitter, astringent sap, containing hydrocyanic 

 acid. Leaves simple, alternate, generally serrate. Flowers in 

 clusters, perfect, white, with parts distinct. Fruit a fleshy, 

 I -seeded drupe, with smooth skin and stone. 



KEY TO SPECIES 



A. Flowers axillary, in sessile umbels; fruit with oval, 

 flattened stone. Plums 



B. Fruit red or yellow, without bloom. 



C. Leaves broadly elliptical, taper pointed, dull 

 green, thick; twigs thorny. 

 D. Petioles bearing 2 glands near base of leaf; 

 pit much compressed. {P. nigra) Canada plum 

 DD. Petioles without glands, pit thick. 



{P. Americana) wild red plum 

 CC. Leaves broadly oval, finely serrate, leathery; 



pit grooved at back. (P. subcordata) pacific plum 

 CCC. Leaves lanceolate, thin, shining; petioles glandu- 

 lar; pit thick. 

 D. Twigs stout, stiff, usually thornless; leaves 

 broad; fruit thick skinned. 



(P. horiulana) wild-goose plum 

 DD. Twigs slender, supple, thorny; leaves narrow; 

 fruit thin skinned. 



(P. angustijolia) chickasaw plum 

 BB. Fruit blue or black, with pale bloom, small. 

 C. Petioles not glandular at apex. 



D. Leaves lanceolate to ovate, long pointed. 



(P. Alleghaniensis) alleghany sloe 

 DD. Leaves oblong or obovate, blunt pointed. 



(P. umhellata) black sloe 

 AA. Flowers axillary, in umbels; fruit small, red, shining, 

 globular. Bird Cherries 



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