246 DRUPACEAE. [VOL. II. 



Family 45. DRUPACEAE DC. Fl. Fran. 4: 479. 1805. 



PI.UM FAMILY. 



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

 ing prussic acid, bitter. Leaves alternate, petioled, serrate, the small stipules 

 early deciduous, the teeth and petiole often glandular. Flowers corymbose, 

 umbelled, racemed or solitary, regular, mostly perfect. Calyx inferior, decidu- 

 ous, free from the ovary, its tube obconic, campanulate or tubular, 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 distributed, most abundant in the north temperate zone. 



Drupe glabrous. I. Prunus. 



Drupe velvety. 2. Amygdalus. 



i. PRUNUS L. Sp. PI. 473- 1753- 



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, dis- 

 tinct; filaments filiform. Style terminal; stigma peltate or truncate. Exocarp of the drupe 

 fleshy, glabrous, the endocarp bony, smooth or a little roughened, globose or oval, or oblong 

 and compressed. [Ancient Latin name of the Plum-tree.] 



About 90 species, natives of the north temperate zone, tropical America and Asia. Besides the 

 following, some 12 others occur in the southern and western parts of North America. The genus 

 is often divided into Prunus proper, the plums, and Cerasus, the cherries; but other than flavor, 

 there appears to be no salient feature separating the two groups. 



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 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 8"-i2" 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. Gravesit. 

 Drupe 3" -5" in diameter; prairie plant. 9. P. gracilis. 



Umbels only i-2-flowered. 10. P. sfinosa. 



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

 Flowers 3 -6" broad; low shrubs. 



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



Leaves oval, oblong, or slightly obovate. 



Petioles 4"-io' r long; drupe 4" -5" in diameter; eastern. 12. P. cuneata. 



Petioles 2"~3" long; fruit 6"-8" in diameter; western. 13. P. Besseyi. 



Flowers 9"-is" broad; trees; leaves ovate. 



Leaves glabrous; pedicels short; fruit sour. 14. P. Cerasus. 



Leaves pubescent beneath, at least on veins; pedicels long; fruit sweet. 



15. P. Avium. 



t t Inflorescence more or less corymbose: leaves shining. 16. P. Pennsylvania. 



5f -X- Flowers corymbose, terminating twigs of the season. 17. p. Mahaleb. 

 X- -Sf Flowers racemed, terminating branches of the season. 



Fruit red, astringent; leaves obovate or oval. 18. P. Virginiana. 

 Fruit purple or purplish-black, sweet or bitter. 



Leaves oval or obovate; fruit purple; shrub or small tree. 19. P. demissa. 



Leaves oblong-acuminate; fruit black; large tree. 20. P. serotina. 



