NATIVE AMERICAN SPECIES OF PRUNUS. 47 
represent its parentage. Nevertheless, the close resemblance to P. 
angustifolia in some of the flower characters, particularly the calyx 
lobes, which are entirely without glands, suggests either that species 
or P. angustifolia varians as one of the parents. A bybrid of the Wild 
Goose and P. cerasifera might also be expected to produce a form 
with larger and longer leaves than the Marianna. 
PRUNUS ORTHOSEPALA Koehne. 
Prunus orthosepala Koehne, 1893, Deut. Dendrol., p. 311. 
Leaves (Pl. IV, fig. 3) varying from oblong-lanceolate to obovate- 
lanceolate, mostly 4 to 6 cm. long, 1 to 2.5 cm. broad, narrowed at 
the base and acute or acuminate at the apex, the margins serrate 
with acute or more often slightly obtuse teeth, these occasionally 
tipped with a callous poimt, bright green, glabrous, and somewhat 
_ lustrous on the upper surface, pale green and glabrous or with a few 
scattered hairs along the rather prominent midvein; petioles 8 to 15 
mm. long, puberulous along the upper surface and eglandular or with 
one or two glands near the upper end. Flowers appearing the last 
of April or early in May, 10 to 14 mm. broad in 3 to 4 flowered umbels; 
pedicels 3 to 5 mm. long, glabrous; calyx tube campanulate, 2 to 2.5 
mm. long, glabrous, the oblong obtuse lobes about 2 mm. long, 
glabrous or nearly so on the outer surface, ciliate on the margin and 
sparingly pubescent within, dentate or entire at the apex; petals 
_ oblong-obovate, 4 to 5 mm. long, 2.5 to 3 mm. broad, entire or erose 
at the apex, white, or in age with a distinct pinkish tinge. Fruit 
ripening at the Arnold Arboretum about the middle of September, 
globose, about 2.5 cm. in diameter, red with white dots, and covered 
with bloom; stone oval (Pl. XIII, fig. 1), about 15 mm. long, 12 mm. 
broad, slightly pointed at the base and rounded at the apex, rather 
irregularly grooved near the ventral suture, grooved along the dorsal 
_ edge, and the surface obscurely rugose. 
Prunus orthosepala, as it grows in: the few American arboreta where 
it is cultivated, is a much-branched, spreading shrub about 5 feet high. 
The bark of the stem and larger branches separates in platelike scales ; 
that of the smaller branches is dark brown in color, marked with 
_ lighter colored lenticels, while that of the young branchlets is chestnut 
colored. 
The history of this species, as given by Sargent (67), is as follows: 
In June, 1880, Dr. George Engelmann, of St. Louis, sent to the Arnold Arboretum 
a package of seeds marked ‘‘Prunus sp., southern Texas.’’ Plants were raised from 
these seeds, and in 1888, or earlier, they flowered and produced iruit which showed | 
_ that they belonged to a distinct and probably undescribed species. A name, how- 
_ ever, was not proposed for it, and, in 1888 probably, plants or seeds were sent to Herr 
Spath, of the Rixdorf Nurseries, near Berlin, where this plum was found in flower by 
_ Dr. Emil Koehne, who has described it under the name of Prunus orthosepala. 
