DRUPACEAE. 523 



usually narrowed at the base, 2-5 cm. long, short-petioled; cymes many-flowered; 

 pedicels and calyx pubescent; calyx-lobes ovate; flowers about 6 mm. broad; styles 

 5; fruit scarlet, depressed-globose, about 4 mm. high, bitter. In thickets, escaped 

 from cultivation, S. Penn. to Ala. and Tenn. Native of Europe and Asia. May. 



Family 13. DRUPACEAE DC. 

 Plum Family. 



Trees or shrubs, the bark exuding gum, the foliage, bark and seeds 

 containing prussic acid, bitter. Leaves alternate, petioled, serrate, the 

 small stipules early deciduous, the teeth and petiole often glandular. 

 Flowers regular, mostly perfect. Calyx inferior, deciduous, free from the 

 ovary, 5-lobed. Disk annular. Calyx-lobes imbricated in the bud. Petals 

 5, inserted on the calyx. Stamens numerous, inserted with the petals. 

 Pistil i in our genera; ovary i -celled, 2-ovuled ; style simple; stigma 

 mostly small and capitate. Fruit a drupe. Seed i, suspended; endosperm 

 none; cotyledons fleshy. About 6 genera and no species, widely dis- 

 tributed, most abundant in the north temperate zone. 



Drupe glabrous. i. Pr units. 



Drupe velvety. 2. Amygdalus. 



i. PRUNUS L. 



Shrubs or trees, mostly with edible fruits, the white or pink flowers variously 

 clustered, the leaves conduplicate or convolute in vernation. Petals spreading. 

 Stamens 15-20, distinct ; filaments filiform. Style terminal ; stigma peltate or 

 truncate. Exocarp of the drupe fleshy, the endocarp bony, smooth or a little rough- 

 ened, globose or oval, or oblong and compressed. [Ancient Latin name of the 

 Plum-tree.] About 90 species, natives of the north temperate zone, tropical Amer- 

 ica and Asia. Besides the following, some 12 others occur in southern and western 

 N. A. 



* Flowers in lateral scaly umbels or fascicles, expanding with or before the leaves, 

 f Inflorescence umbellate, the clusters sessile or nearly so. 



Leaves convolute in vernation; fruit mostly large; pit more or less flattened. 

 Umbels several-flowered. 



Leaves abruptly acuminate : drupe red or yellow. 



Calyx-lobes entire, pubescent within ; fruit globose, i. P. Americana. 

 Calyx-lobes glandular-serrate; fruit subglobose or oval. 

 Calyx-lobes glabrous within; leaves oval or obovate. 



2. P. nigra. 

 Calyx-lobes pubescent on both sides; leaves ovate-lanceolate. 



3. P. hortulana. 

 Leaves acute, gradually acuminate, or obtusish ; drupe red or purple. 



Leaves glabrous when mature. 



Fruit red, with little bloom or none. 



Leaves lanceolate ; drupe thin-skinned. 4, P. angustifolia. 



Leaves ovate-lanceolate or oblong ; drupe thick-skinned : western 



shrub. 5. p. Watsoni. 



Fruit dark purple, with a bloom ; leaves ovate. 6. P. Alleghaniensis. 

 Leaves pubescent, at least on the lower surface, when mature. 

 Drupe 1.5-2.5 cm. in diameter; coast plants. 



Leaves ovate or oval, acute ; stone pointed at both ends. 



7. P. maritima. 

 Leaves orbicular, very obtuse ; stone pointed at base. 



8. P. Gravesii. 

 Drupe 0.6-1 cm. in diameter ; prairie plant. 9. P. gracilis. 



Umbels only 1-2 flowered. 10. P. spinosa. 



Leaves conduplicate in vernation ; fruit mostly small ; pit mostly globose. 

 Flowers 6-12 mm. broad ; low shrubs. 



Leaves oblanceolate or spatulate ; northern. u. P. pumila. 



Leaves oval, oblong, or slightly obovate. 



Petioles 8-20 mm. long ; drupe 8-10 mm. in diameter ; eastern. 



12. P. cuneata. 

 Petioles 4-6 mm. long; fruit 12-16 mm. in diameter ; western. 



13. P. Besseyi. 



