AMYGDALACEAE 571 



Twigs closely pubescent. 



Corolla 6-8 mm. broad : drupe 8-10 mm. long. 10. P. normalis. 



Corolla 14-20 mm. broad : drupe 12-15 mm. long. 11. P. injucunda. 



B. Drupe red or orange, without bloom, mostly over 20 mm. thick. 

 Sepals glandular-ciliate or glandular-serrate or merely ciliate. 



Sepals ciliate or glandular-ciliate, otherwise glabrous : leaf-blades 



minutely toothed. 



Leaf-blades with acuminate tips, serrate : drupe 15-20 mm. long. 12. P. rivularis. 

 Leaf-blades obtuse or merely acute, serrulate : drupe 20-26 mm. 



long. 



Sepals ciliate with simple hairs : drupe thick-skinned. 13. P. Watsonii. 



Sepals ciliate with glandular hairs : drupe thin-skinned. 14. P. angusttfolia. 



Sepals glandular-serrate, pubescent, at least within: leaf-blades 



rather coarsely toothed. 



Sepals pubescent on both sides. 15. P. hortulana. 



Sepals pubescent within. 16. P. nigra. 



Sepals entire, not glandular-ciliate. 17. P. Americana. 



1. Prunus minutiflora Engelm. A low rigid intricately-branched shrub 3-7 dm. 

 tall. Leaf-blades leathery, obovate or cuneate, 1-2 cm. long, clustered on shortened 

 branches, rounded or obtuse at the apex, entire or coarsely toothed with glandless teeth, 

 minutely pubescent beneath or glabrous, cuneately narrowed into short petioles : flowers 

 usually solitary, very short-pedicelled : sepals not glandular-toothed : drupes ovoid or 

 globose-ovoid, 8-12 mm. long, velvety. 



On prairies, Texas. 



2. Prunus glandulosa Hook. A low diffuse, somewhat thorny shrub, with zigzag 

 branches. Leaf-blades oblong or oblong-elliptic, 2-2.5 cm. long, obtuse at the apex, ser- 

 rate with gland-tipped spreading teeth, rather acute at the base, pubescent on both sides, 

 short-petioled : clusters usually 2-flowered, or the flowers sometimes solitary : pedicels 

 mostly less than 1 cm. long, finely pubescent : sepals oblong, about as long as the hy- 

 panthium, conspicuously glandular-toothed : petals obovate, much longer than the sepals : 

 drupes subglobose, velvety. 



On prairies, Texas. 



3. Prunus Pennsylvania L. f. A small tree, with a smooth aromatic bark and 

 glabrous foliage. Leaf-blades thinnish, oblong-elliptic to nearly oval or lanceolate, 8-15 

 cm. long, acuminate at the apex, doubly serrate, acute or rounded at the base ; petioles 

 slender, 1-1.5 cm. long : flowers in lateral sometimes peduncled clusters : pedicels 

 slender, 1-2.5 cm. long or 3 cm. long at maturity : corolla 10-12 mm. broad : drupea 

 globose, 4-7 mm. in diameter, red, without bloom, with thin sour flesh : stone subglobose, 

 or slightly elongated. 



In rocky or open woods, Newfoundland to the Rocky Mountain region, south to Georgia. WILD- 

 RED CHEERY. PIN or PIGEON CHERRY. 



4. Prunus cuneata Raf. A low spreading shrub 3-12 dm. tall, with glabrous foliage. 

 Leaf-blades firm, oblong, oval or somewhat obovate, 3-8 cm. long, sometimes acute at both 

 ends, cuneate at the base, bright green above, glaucous beneath, rather coarsely serrate 

 with appressed teeth ; petioles 8-20 mm. long : flowers in clusters appearing with the 

 leaves: pedicels 1-1.5 cm. long: corolla about 1 cm. broad, white or nearly so: drupes 

 subglobose, 8-10 mm. in diameter. 



In moist, sometimes rocky soil or meadows, New Hampshire to Wisconsin, Minnesota and North 

 Carolina. DWARF CHERRY. 



5. Prunus C6rasus L. A relatively small tree. Leaf -blades ovate, oval-ovate or 

 ovate-lanceolate, 4-11 cm. long, abruptly acute or acuminate, serrate-dentate, glabrous,, 

 resinous when young : flowers in lateral clusters from scaly buds : pedicels about 3 cm. 

 long during an thesis : corolla 1.5-2.5 cm. broad : drupes nearly globose, 8-10 mm. in di- 

 ameter, or larger in cultivation, sour, red or black, without bloom : stone subglobose. 



In woods and thickets, New York to Pennsylvania and Georgia, escaped from cultivation. Native 

 of Europe. SOUR CHERRY. 



6. Prunus Avium L. A tree becoming 23 m. high. Leaf-blades ovate to oval or 

 oval-ovate, 5-10 cm. long, abruptly short-acuminate, serrate, pubescent beneath, sometimes 

 only on the nerves : flowers in lateral clusters from scaly buds : pedicels slender, 25-36 mm. 

 long during anthesis : corolla 2.5-3 cm. broad : drupes subglobose, 8-10 mm. in di- 

 ameter, sweet, without bloom : stone globular. 



In open woods and thickets, Connecticut to Pennsylvania and Georgia. Escaped from cultivation. 

 Native of Europe. SWEET CHERRY. 



7. Prunus umbellata Ell. A low shrub or small tree, sometimes 6 m. tall, with a 

 slender, erect or ascending trunk. Leaf-blades thinnish, oblong, elliptic or nearly oval, 

 sometimes broadest above or below the middle, short-acuminate, or merely acute, serrate, 

 rounded or acute at the base, glabrous on both sides or sparingly pubescent beneath, on 

 short slender petioles : flowers expanding before the leaves, in lateral clusters : pedicels. 



