NATIVE AMEEICAN SPECIES OP PRUNUS. 57 



Petjnus Maeitima Hybeids. 



Hybrids have been produced by Luthur Burbank and J. W. Kerr. 

 Am ong 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 J 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. (PI. XIII, fig. 10.) 



Prunus Gravesh Small. 



Pruniis gravesii Small, 1897, in Bill. 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 soUtary, 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 2.5 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 (PI. 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 maritima 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 Gracilis Engel. and Gray. 



Prunus gracilis Engelm. and Gray, 1845, in Boston Jour. Nat. Hist., v. 5, No. 2, 



p. 243. 

 Prunus chicasa normalis Torr. and Gray, 1840, Fl. N. Amer. v. 1, p. 407. 

 PruniM normalis Small, 1903, Fl. Southeast. United States, p. 572. 



Leaves oval (PI. \TT, fig. 1), rarely ovate, or still more rarely 

 obovato-lanceolato, 2.5 to 5 cm. long, 1.5 to 2.5 cm. broad, pointed at 

 eacli end or rarely obtuse at the apex, finely and obscurely pubescent 



