P. americana (in part). 8. Torrey and Gray Fl. N. Am. 1:407. 1840. 9. Torrey Fl. N. Y. 1:194. 1843. 10. Emerson Trees of Mass. Ed. 2, 2:511. 1846. 11. Nuttall Silva 2:19. 1852. 12. Sargent 10th Cen. U. S. 9:65. 1883. 13. Watson and Coulter Gray’s Man. Ed. 6:151. 1889. 14. Gray For. Trees N. A. 46, Pl. 1891.
P. americana nigra. 15. Waugh Vt. Sta. Bul. 53:60, fig. 1896. 16. Ibid. Vt. Sta. An. Rpt. 10:102. 1897. 17. Bailey Cyc. Am. Hort. 1449. 1901.
P. mollis. 18. Torrey Fl. U. S. 1:470. 1824.
Tree small, seldom exceeding twenty feet in height; trunk attaining six or eight inches in diameter, bearing the head at three to five feet from the ground; bark thin, one-quarter inch thick, from dark red to a light gray-brown, rough, but not shaggy, surface covered with thick scales; branches upright, stout, rigid, forming a compact rather narrow head, armed with stout, spiny spurs; branchlets more or less zigzag, glabrous or tomentose, green, later becoming reddish-brown; lenticels few or many, pale, slightly raised.
Winter-buds of medium size, conical or long-acuminate, reddish-brown; leaves large, broad-oval, ovate or obovate, with a long acuminate apex and cuneate or subcordate base; margins doubly crenate-serrate with teeth tipped with glands which disappear as the leaves mature; thin and firm in texture; upper surface light green, glabrous, the under surface paler, pubescent when young and pubescent at maturity on some soils; midribs coarse but veins rather slender; petioles two-thirds inch long, rather stout, with two, sometimes but one, large, dark red glands near the blade, pubescent and tinged with red; stipules lanceolate, sometimes lobed, one-half inch in length.
Flowers expanding early, before or with the leaves, large, sometimes one and one-half inches across; borne in three or four-flowered lateral umbels on slender, glabrous, red pedicels one-half inch or more in length; calyx-tube obconic, outer surface red, inner surface pink; calyx-lobes glabrous on both surfaces or with a few, straight, scattered hairs on the inner surface, pinkish, acute, glandular; petals pink, turning a darker pink in fading, rather broadly ovate, apex rounded, base a short claw, margins erose; stamens with yellow anthers; filaments one-half inch long; pistils glabrous, shorter than the stamens.
Fruit ripening comparatively early; globose or oval, usually somewhat oblong, an inch or more through the long diameter, red, orange or yellowish in color, with little or no bloom; skin thick, tough and astringent; flesh yellow, firm, meaty, often acid or astringent; stone usually clinging, large, oval, compressed, thick-walled, with a sharp ridge on the ventral and a slight groove on the dorsal suture.
It is possible that a group of Nigras, those occurring in western Wisconsin and Minnesota and about the upper extremity of Lake Superior ought to be described as a sub-species since they have a somewhat different aspect of tree and the fruits are a darker shade of red and show more bloom; the calyx is more pubescent and the calyx-glands more sessile. The differences in environment may change these characters, as indicated above, but they seem very constant in the cultivated varieties of the groups, most of which come from the west, and therefore sufficient to segregate this form from the species.
The Nigra is the wild plum of Canada. Its most common name, “Canada Plum,” is distinctly applicable and is here supplanted by “Nigra” only for the sake of uniformity. This is undoubtedly the dried plum which Jacques Cartier saw in the canoes of Indians, in his first voyage of discovery up the St. Lawrence in 1534.[120] These primitive prunes, Cartier says, the Indians called “honesta.” In his second voyage, the next year, he enumerates among other fruits the plum, “prunier,” growing on the “Ysle de Bacchus,” named from its “Vignes.” Dried plums, we learn from many later accounts, were a staple article of the winter diet of the savages. That the Indian tended the trees is probable, for the early explorers often record that plantations of plums were found about the aboriginal towns. Undoubtedly the range of this species was greatly extended by the Indians.
The Nigra is the most northern of the American plums, being an inhabitant of a region bounded on the north by a line passing from southern New Foundland westward to the Strait of Mackinac and thence southward to Lansing, Michigan. Its southern boundary can be but illy defined, but the species is common in New England, northern New York, where it is sometimes cultivated about houses, and westward at least as far as the eastern shore of Lake Michigan for the species, while the western form reaches the western boundary of Minnesota at least. Small[121] reports it as far south in the Appalachian System as northern Georgia. In the great region outlined above it is distributed in more or less scattered localities, being found usually in the valleys of rivers and streams, though often on high lands and in open woods, in the last locations preferring a limestone formation.