PLUM FAMILY 451 



2. P. americana Marsh. Tree 5-11 m. high, or rarely a shrub 1-5 m., 

 more or less spiny, with glabrous twigs; leaves firm, lanceolate, elliptic, or obovate, 

 4-10 cm. long, acute or rounded at the base, acuminate at the apex, sharply 

 toothed, glabrous, or somewhat hairy along the veins beneath; fruit subglobose 

 or round-eUipsoid, 2-2.5 cm. long, orange, bright red, or purplish. Along rivers 

 and in thickets: N.Y.— Fla.— Tex. — Co'lo. — Mont. PlainSuhmont. Mr-My. 



3. P. prunella Daniels. Undershrub, thornless, traihng or ascending, 3-6 

 dm. high; twigs reddish; leaves lanceolate, 3-5 cm. long, sharply serrate, except 

 the entire acuminate base, glossy green above, paler beneath; fruit ellipsoid, 

 1.3-1.5 cm. long and 1 cm. thick, black-purple, with a slight bloom. Table land: 

 Colo. Suhmont. 



4. P. Besseyi Bailey. Shrub, with spreading or prostrate branches, 0.5-1.5 

 m. long; leaves oblanceolate or elliptic, cuneate at the base, acute at the apex, 

 serrate; flowers in sessile umbels, opening with the leaves; fruit 12-16 mm. in 

 diameter, globose, black, often mottled, somewhat astringent. Sand hills: Man. 

 — Minn. — Kans. — Colo. — Wyo. Plain. My-Je. 



6. P. ignota A. Nels. "Shrubby or possibly becoming tree-like; branches 

 slender, none of them becoming indurated or thorny; leaves glabrous from the 

 first, simply and sharply serrate; flowers white [or pinkish], appearing with or 

 after the leaves, solitary or 2 or 3 in a cluster; calyx [hypanthium] turbinate; 

 lobes entire, glabrous within and nearly so without; petals obovate." [Perhaps 

 one of the cultivated Japanese cherries, escaped, but species not identified.] 

 Banks: Colo. Plain. My. 



6. P. pennsylvanica L. f. A small tree, or shrub, sometimes 12 m. high; 

 leaves oval to lanceolate, acute or acuminate at the apex, rounded or acute at 

 the base, glabrous and shining on both sides, serrulate; inflorescence corymbose, 

 leafless, peduncled or sessile, unfolding with the leaves; fruit globose, red, 4-6 

 mm. in diameter, sour. Rocky woods and along streams: Newf. — Ga. — Colo. — 

 N.D. Plain — Suhmont. Ap-Je. 



7. P. corymbulosa Rydb. A small shrub, 1-2 m. high; leaves glabrous 

 and shining, 4-6 cm. long, ovate-lanceolate, acute or acmninate, finely serrulate; 

 corymbs 3-6-flowered, peduncled, usually subtended by 1 or 2 small leaves; 

 sepals erose; petals more or less pubescent; fruit globose, red. Cerasus tricho- 

 pe/aZa Greene. Hills: Mont. — Wyo. Suhmont. My-Je. 



8. P. emarginata (Dougl.) Walp. A tree up to 8 m. high, with glabrous, 

 red, shining branches; leaves eUiptic, obovate, or oblanceolate, 3-8 cm. long, 

 rounded or obtuse at the apex, crenate, with gland-tipped teeth, dark green 

 above, paler beneath; sepals rounded at the apex, entire; petals obovate, greenish 

 white; fruit 8-12 mm. in diameter, dark red or almost black to lemon-yellow. 

 Cerasus padifolia Greene. Hillsides: B.C. — Ida. — Nev. — Calif. Suhmont. Ap-Je. 



9. P. prunifolia (Greene) Shafer. A tree rarely 15 m. high, with grayish 

 brown branches, at first finely pubescent, in age glabrous; leaves elliptic or 

 obovate, or rarely oval, 4-9 cm. long, rounded or obtuse, or on vigorous shoots 

 acute at the apex, crenate, with gland-tipped teeth, dark green above, paler and 

 villous beneath; sepals blunt, villous; petals white, obovate; fruit 8-12 mm. in 

 diameter, bright red or purple. Cerasus mollis Dougl. C. prunifolia Greene. 

 P. mollis Walp., not Torr. Hills and copses: B.C. — Ida. — Ariz. — CaUf. Suh- 

 mont. Ap-Je. 



10. P. valida (Woot. & Standi.) Rydb. Tree 5-8 m. high; branches stout, 

 dark reddish brown, densely and finely pubescent when young; leaf -blades 

 obovate, oval, or elliptic, 5-7 cm. long, rounded or subcordate at base, green 

 and glabrous above, glaucescent and pubescent beneath, serrulate with inflexed 

 teeth; peduncle stout, pubescent, often recurved above; fruit black, 10-12 mm. 

 thick. PadusvalidaWoot.& Standi. Canons: N.M. — seUtah. Suhmont. Je. 



11. P. demissa (Nutt.) Walp. Tree up to 15 m. high; twigs densely 

 pubescent when young; leaves obovate or oblong-obovate, 5-10 cm. long, rounded 

 or subcordate at the base, sharply toothed, paler and pubescent at least on the 

 veins beneath; peduncles 7-10 cm. long, more or less pubescent; petals about 5 



