POLYPETALOUS EXOGENOUS PLANTS. 251 



Fruit of 1-5 bony l-sceded nutlets Cratjeovs. 



2-5 cartilaginous or membranaceous 2-seeded cells Ptrus. 



3-5 two-seeded cells ; seeds separated by false partitions . . Amelancuier. 



PRUNUS. Plum Cherry. 



Calyx 5-cleft, deciduous; petals 5, spreading; stamens 

 15-30 ; ovary with 2 collateral suspended ovules ; styles 

 terminal ; drupe fleshy ; the stone even. — Trees or shrubs; 

 leaves simple ; floivers white. 



Prunus. (Plum.) Drupe glaitcous ; stone more or 

 less compressed ; leaves convolute in the hud ; floivers in 

 lateral clusters, appearing hefore the leaves ; branches 

 often sp)iny. 



P. Americana, Marsh. Leaves thick, ovate or some- 

 what obovate, acuminate, rounded or slightly cordate at 

 the base, pubescent beneath, sharply serrate, on glandular 

 petioles ; drupe large, globose. — A small tree ; leaves 2 '-3' 

 long, smooth when old ; floiuers very numerous ; 7^/?^??^ 

 roundish, ^ -1' in diameter, pleasantly acid ; ripening in 

 September. 



P. umbellata. Ell. Leaves thin, ovate-lanceolate or 

 oblong, acute at both ends, or the upper ones rounded at 

 the base, finely and sharply serrate, smooth or soft-downy 

 beneath ; calyx-ieeth. emarginate, pubescent ; drupe globose ; 

 stone slightly compressed ; branches purple, shining; leaves 

 I'-iy long. — Tree ox shrub; plum rarely I' in diameter, 

 dark-purpled or black, sour and bitter ; ripening in August. 



P. Chicasa, Michx. Leaves thin, lanceolate or oblong- 

 lanceolate, acute, smooth, minutely and sharply serrate, 

 with the glandular and incuY^Qd flouwrs short-peduncled; 

 calyx smooth ; drupe yellowish -red, globose. — A shrub or 

 small tree; leaves l^'-2' long; j)lnin^' in diameter, thin- 

 skinned, and of an agreeable flavor. 



