AMYGDALACEAE 573 



pedicels about 1 cm. long : corolla white or creamy, 10-15 mm. broad : drupes oval-globose, 

 22-26 mm. long, red or yellowish, with a slight bloom : stone ovoid, hardly flattened, acute, 

 one of the rounded edges slightly grooved. 



In dry soil or thickets, New Jersey to Florida, Alabama and the lower Mississippi Valley. CHICK 

 ASAW PLUM. 



15. Prunus hortulana Bailey. A small tree resembling P. Americana and P. nigra 

 in habit, with a thin bark and spreading branches. Leaf-blades ovate to ovate-lanceolate 

 or oval, 10-15 cm. long, long-acuminate, glandular-serrate ; petioles less than 2.5 cm. long, 

 usually with 2 or several glands near the blade : flowers in lateral clusters preceding the 

 leaves : pedicels 1-2 cm. long: sepals glandular-serrate : corolla 1.5-2 cm. broad : drupes 

 subglobose or oval-globose, 20-23 mm. long, bright red, with a thin skin : stone somewhat 

 swollen, roughened, neither margined nor crested. 



In thickets and woods, Illinois and Tennessee to Alabama, Arkansas and Texas. A variety with 

 thick, dull, coarsely serrulate sometimes oblanceolate leaf-blades prominently nerved beneath, and 

 a smooth stone is P. hortulana Mlneri Bailey ; it occurs in Tennessee, Illinois and Missouri. WILD GOOSE 

 PLUM. 



16. Prunus nigra Ait. A small tree, rarely 10 m. tall, with a trunk sometimes 3 dm. 

 thick. Leaf-blades firm, elliptic to oval, 6-12 cm. long, acuminate at the apex, sharply 

 and mostly doubly serrate, obtuse or rounded at the base, bright green and glabrous above, 

 usually sparingly pubescent beneath ; petioles 1-2 cm. long, with two red glands near the 

 blade : flowers 3-5 in lateral clusters : pedicels 1-2 cm. long : sepals glandular-serrate : corolla 

 about 3 cm. broad : drupes oval or subglobose, 2.5-3 cm. long, orange-red, with a slight 

 bloom and thick skin : stone oval, flattened, acutely crested on the ventral edge. 



In woods or clearings, Newfoundland to Wisconsin, Alberta and Georgia. HORSE PLUM. 



17. Prunus Americana Marsh. A small, somewhat spiny tree, sometimes 10 m. tall, 

 with a maximum trunk diameter of about 3 dm. Leaf-blades firm, elliptic to oval, or 

 oval-obovate, 4-10 cm. long, acuminate, sharply singly or doubly serrate, pubescent beneath 

 especially near the nerves, acute or rounded at the slightly inequilateral base ; petioles 

 0.5-2 cm. long, usually glandless : flowers 2-5 in lateral clusters appearing before the 

 leaves : pedicels 1-2 cm. long : sepals entire : corolla 1.5-2.5 cm. broad : drupes subglo- 

 bose or barely elongated, 18-25 mm. long, with a tough skin and sometimes a slight bloom : 

 stone ovoid or oval, flattened, not crested along the ventral suture. 



In woods and thickets, New York to Montana, Florida and Colorado. WILD YELLOW PLUM. 

 RED PLUM. The variety with copiously pubescent leaves and twigs, is P. Americana landta Sudw. ; it 

 occurs mainly in the Gulf States west of the Mississippi River and in the contiguous states. 



4. PADUS Borckh. 



Shrubs or trees, manifestly pervaded with prussic acid. Leaves alternate, deciduous : 

 blades various, simple, usually toothed, petioled. Flowers perfect, in racemes terminating 

 in leafy branches of the season, following the leaves, pedicelled. Hypanthium often cam- 

 panulate. Sepals 5, short. Petals 5, white, imbricated, inserted in the throat of the hypan- 

 thium. Stamens 15-30, inserted with the petals: filaments slender, distinct. Ovary 

 sessile, 1-celled. Style simple. Ovules 2, pendulous. Drupe with a pulpy exocarp, not 

 glaucous, indehiscent : stone nearly as thick as broad, bony. Seed solitary. 



Sepals deciduous : leaf-blades mostly serrulate with very slender teeth. 1. P. Virginiana. 



Sepals persistent : leaf-blades mostly serrulate with relatively coarse teeth. 

 Young shoots, raceme-rachis and pedicels glabrous. 



Sepals deltoid, slightly broader than long : leaf-blades delicately reticulated. 2. P. eximia. 

 Sepals ovate, longer than broad : leaf-blades not reticulated. 3. P. serotina. 



Young shoots, raceme-rachis and pedicels pubescent. 



Leaf- blades finely and rather sparingly pubescent beneath (except along the 

 midrib), becoming glabrate and glaucous with age. 

 rupe red : leaf-blades prevailingly obovate. blunt. 

 Drupe purple : leaf-blades ovate, oblong or elliptic, acute or acuminate. 5. P. Alabamensis. 



Drupe red : leaf-blades prevailingly obovate. blunt. 4. P. Cuthbertii. 



Drupe purple : leaf-blades ovate, oblong or elliptic, acute or acuminate. 

 Leaf-blades densely and permanently clothed with tawny or rufous tomen- 



tum, not glaucous. 6. P. australis. 



1. Padus Virginiana (L. ) Roem. A shrub or small tree, sometimes 12m. tall, with 

 spreading or drooping branches and a very bitter bark. Leaf-blades thinnish, oval or 

 obovate, 5-10 cm long, short-acuminate at the apex, sharply serrate, usually rounded at the 

 base, glabrous or nearly so on both sides ; petioles 1-2 cm. long, slender : racemes rather 

 lax, 8-15 cm. long: sepals reflex ed : corolla 8-10 mm. broad : drupes globose, 8-10 mm. 

 in diameter, red or almost black, or rarely yellow, very astringent. [Prunus Virginiana L. ] 



In rocky soil or on river banks, Newfoundland to Manitoba and British Columbia, south to Georgia, 

 Texas and Colorado. Spring. CHOKE CHERRY. WILD CHERRY. 



2. Padus eximia Small. A tree becoming 26 m. tall, with loosely spreading branches 

 and glabrous twigs. Leaf -blades relatively thin, mainly ovate, varying to oblong, oblong- 



