Trkes of the North kk.n L'nitki) Statks 7'> 



'i. Leaves glabrous or nearly so. o. 



4. Leaves pubescent beneath, at least on the veins, with 

 prominent hairs; inflorescence umbellate; drupe sweet. 

 /'. ariuin. 

 :>. Leaves ovate-lanceolate to lanceolate ; inflorescence more 

 or less corymbose; drupe with thin sour flesh. P. 

 f^eunsyli'iDiico. 

 :.. Leaves ovate to ovate-lanceolate; inflorescence umbellate. 



drupe with thick sour flesh. P. cerasus. 

 (]. Leaves oval-lanceolate to ovate, acuminate or acute; 

 olands on the petiole usually elongated and tooth-like; 

 bark black; drupe dark-purple or black, sweet. P. 

 7'ir(iiniaua. 

 ti. Leaves oliovate to oval, abruptly acute or acuminate; 

 glands on the petiole usually rounded or disk-like; 

 liark gray; drupe red or purple, astringent. P. nana. 

 7. Leaves abruptly acuminate, petiole much less than \ as 



long as the blade. 8. 

 7. Leaves abruptly long-acute or acuminate, ovate to round- 

 ovate; iK'tiole I as long as the blade; flowers solitary 

 (.r in twos; fruit velvety. P. armcnia'ca. 

 7. Leaves acute or ohtusish. or gradually acuminate. 10. 

 S. Leaves mostly broad and thick, somewhat pui)escent or 

 roughish l)eneath ; calyx lobes puliescent or glabrous 

 within. !'. 

 S. Leaves mostly narrow and ])each-like. firm and more or 

 less shining, glabrous; calyx lo1)es pubescent on both 

 sides. /'. horlnlana. 

 !i. Calyx-lobes entire, i)nl)escent witbin : fruit gloliose ; 



llowers wliite. /'. anicricana. 

 !». Calyx lobes glandular-serrate, glabrous witbin; fruit 

 subglobose (.r oval; flowers white, turning pink. /'. 

 niiira. 



10. Leaves glabrous when mature, acute or acuminate. 11. 

 In. Leaves pubescent beneath, not pointed or only slightly 



SQ, ovate or obovate. P. domcsiica. 



11. Leaves lanceolate; drupe red witb little or no bloom. /'. 



anciustifolia. 

 11. Leaves ovate, drupe dark ptirpU'. witli a bloom. P. allr- 

 iihanirnsis. 



