22 BULLETIN 179, U. §. DEPARTMENT OF AGRICULTURE. 
ripening from the second week in August to the end of September; 
stone (Pl. IX, figs. 1 to 7) oblong-oval, rather flat, about 20 mm. long, 
14 mm. broad, obliquely truncate at the base and rounded at the 
apex, grooved on either side a short distance from the ventral edge, 
and with a single groove along the dorsal edge. 
Prunus mgra is a small tree, attaining a maximum height of about. 
30 feet. It sprouts from the roots and frequently forms small thick- 
ets. The grayish bark of the trunk exfoliates in platelike scales, 
while that of the young twigs is smoother and very dark gray. The 
branches are often furnished with spinescent branchlets, and the 
winter buds are lanceolate in outline, acute, and 4 to 5 mm. long. 
The wood is heavy, close grained, and strong. 
While Prunus nigra has often been confused with P. americana, 
it is nevertheless one of the most distinct and easily recognizable of 
the native species. The foliage is distinguished from the latter spe- 
cies by the rounded instead of pointed serrations of the leaves. The 
flowers are larger, have a more pinkish tinge when fading, and appear 
earlier in the same locality; the calyx lobes are glandular serrate and 
usually glabrous, while in P. americana they are inconspicuously 
olandular or eglandular and pubescent within. 
Prunus nigra grows (fig. 1) in the alluvial valleys of streams or 
often on limestone hills, and ranges from the vicinity of the St. John 
River in western New Brunswick through Maine, excepting the 
extreme northern portion, to the valley of the St. Lawrence and west- 
ward to the southern shores of Georgian Bay and nearly to the shores 
of Lake Michigan in the southern peninsula of the State of Michigan. 
It extends southward to central Massachusetts, though probably as 
an introduced plant in that State, but occurs apparently as a native 
at Ithaca, N. Y., and in northern Ohio near the Black River, in 
Lorain County; thence its line of southern distribution moves north- 
ward to the vicinity of Lake St. Clair, Lansing, and Grand Rapids, 
Mich. It does not occur in the sandy soils of the lake region of west- 
ern Michigan, but reappears in northeastern Illinois, extending from 
near Joliet to the southern part of Dodge County md the vicinity of 
Milwaukee, in southeastern Wisconsin. It does not appear to have 
been observed | in central Wisconsin, but is found in the western part 
of the State, where it extends northward from the vicinity of the 
isconsin River and through eastern Minnesota to the region west 
of Port Arthur, in western Ontario, and to the Winnipeg Valley, 
where it was collected by Bourgeau in 1857. 
has collected extensively in New Brunswick and Newfoundland, aay that he has no knowledge of it east 
of the St. John Riversystem. Hesays: ‘‘It is fairly abundant on terraces and limey slopes near the mouth 
of the Aroostook River, which is its northeastern limit, I think.’”? The herbarium material examined con- 
firms this view of the northeastern limit of the species. 
