NATIVE AMERICAN SPECIES OF PRUNUS. 21 
20. Petioles 5 to 10 mm. long, leaves 3.5 to 7 cm. long, obtuse or 
sometimes acute at the apex. Fruit about 10 to 15 mm. in 
diameter. Eastern and northern species..............------ P. cuneata. 
20. Petioles 5 to 6 mm. long, leaves 3 to4.5 cm. long, acute or rarely 
obtuse at the apex. Fruit about 15 to 18 mm. in diameter. 
BR rCeM ORE CIES. 8 28S Sacre cite cig sb eetins wine tos fae clans P. besseyt. 
DESCRIPTIONS OF THE SPECIES AND THEIR HYBRIDS. 
Prunus Niera Ait. 
(Canada plum.) 
Prunus nigra Aiton, 1789, Hort. Kew., v. 2, p. 165. 
Prunus borealis Poir., 1804, in Lam. Encycl., t. 5, p. 674. 
Prunus moliis Torr., 1824, Fl. North and Mid. U.S., v. 1, p. 470. 
Prunus americana nigra Waugh, 1896, in Vt. Agr. Exp. Sta. Bul. 53, p. 58. 
Cerasus borealis Michx., 1803, ? Fl. Bor. Amer., t. 1, p. 286. 
Cerasus nigra Lois., 1812, Nouv. Duham., v. 5, p. 32. 
oe 
Leaves (Pl. I, fig. 2) oval or obovate, mostly 8 to 13 cm. long, 4.5 to 
7 cm. broad, rounded at the base, abruptly acuminate toward the 
apex, green and glabrous above, or with scattered hairs along the 
veins, pale and becoming glabrous below except along the midvein 
and in the axils of the lateral veins, or sometimes with scattered hairs 
along the lateral veins, when young usually somewhat pubescent 
above and rather strongly so below, rarely entirely glabrous, the 
margins rather coarsely and unevenly serrate, the serrations rounded 
and in the young leaves glandular, the glands usually remaining as 
small callous points; petioles 10 to 18 mm. long, pubescent on the 
upper surface with longish hairs, or sometimes entirely glabrous, 
glands one to three near the apex or often entirely absent; stipules 
linear or sometimes lobed, the margins glandular. Flowers 2 to 2.5 
or sometimes even 3 cm. broad, appearing before the leaves from the 
last of April in the southern portion of its range to the last of May in 
northern localities; umbels nearly sessile, mostly 2 or 3 flowered; 
pedicels 10 to 20 mm. long, usually about 18 mm., glabrous or very 
rarely finely pubescent in some western material; calyx usually 
somewhat reddish, in age frequently conspicuously so, the tube rather 
narrowly obconic, about 3.5 to 4 mm. long, or in cultivated trees the 
tube and lobes sometimes each 5 mm. long, glabrous, calyx lobes 
oblong-ovate or oblong-obtuse, glandular serrate, glabrous or rarely 
pubescent on the inner surface mainly toward the base, and still 
more rarely with a few scattered hairs on the outer surface, the lobes 
at length spreading or reflexed; petals white or in age with a decided 
tinge of pink, oblong-ovate to nearly orbicular and abruptly con- 
_ tracted to a claw, 10 to 12 mm. long, 6 to 10 mm. broad, usually erose 
toward the apex, sometimes conspicuously so. Fruit oblong-oval, 
2.5 to 3 cm. long, 1.8 to 2.5 cm. in diameter, orange red or sometimes 
deep crimson, varying to orange yellow, nearly destitute of bloom, 
