NATIVE AMERICAN SPECIES OF PRUNUS. 57 
Prunus Maritiwa Hypring. 
Hybrids have been produced by Luthur Burbank and J. W. Kerr. 
Among those secured by Mr. Kerr are several of remarkably clean 
foliage and vigorous character, probably with Prunus triflora as one 
of their parents. At least one of these has fruit 1} inches in diameter, 
although not of very good quality. Nevertheless, this species shows 
evidence of much promise, and with a careful search among wild 
trees for fruit of good quality as a basis something of value may ulti- 
mately be secured. (Pl. XIII, fig. 10.) 
Prunus Graves Small. 
Prunus gravesii Small, 1897, in Bul. Torrey Bot. Club, v. 24, No. 1, p. 45. 
Leaves orbicular to oblong-orbicular, 18 to 30 mm. long, 20 to 
25 mm. broad, the margin sharply serrate, green and finely pubescent 
or glabrate above, pale green below.and pubescent, at least along the 
veins; petioles about 3 mm. long, pubescent; stipules linear, 
glandular, and pubescent. Flowers appearing before or with the 
leaves from the middle to the last of May, in umbels of 2 to 3 or some- 
times solitary, about 10 to 15 mm. broad; pedicels and calyx pubes- 
cent, pedicels about 6 mm. long; calyx tube 2.5 to 3 mm. long, the 
ovate, obtuse lobes 2 to 2.6 mm. long, pubescent on both surfaces, © 
eglandular; petals about 5 mm. long, orbicular, and contracted near 
the base to a distinct claw. Fruit globose, 10 to 15 mm. in diameter, 
deep purple with light-blue bloom, slightly astringent, ripening 
early in September; stone subglobose or broadly oval (Pl. XII, figs. 
18 and 19), about 8 by 6.5 by 5.5 mm., obscurely ridged on the dorsal 
and thickened on the ventral edge, with a line along the center and 
an indistinct ridge a short distance back on either side. 
The species is a low, unarmed shrub scarcely more than 3 feet high, 
with a dark, rather rough bark and usually puberulent twigs. 
This rare species is related to Prunus maritvma and is known only 
from the original locality at Groton, Conn., where it grows on a grav- 
elly ridge near Long Island Sound (fig. 3). The species was dis- 
covered and the type specimens (in the herbarium of the New York 
Botanical Garden) collected by Dr. Charles B. Graves, for whom it 
is named. 
Prunus Graciuis Engel. and Gray. 
Prunus gracilis Engelm. and Gray, 1845, in Boston Jour. Nat. Hist., v. 5, No. 2, 
p. 248. 
Prunus chicasa normalis Torr. and Gray, 1840, Fl. N. Amer. v. 1, p. 407. 
Prunus normalis Small, 1903, Fl. Southeast. United States, p. 572. 
Leaves oval (Pl. VII, fig. 1), rarely ovate, or still more rarely 
obovate-lanceolate, 2.5 to 5 em. long, 1.5 to 2.5 em. broad, pointed at 
each end or rarely obtuse at the apex, finely and obscurely pubescent 
