1. Bailey Cornell Sta. Bul. 38:23, 1892. 2. Waugh Vt. Sta. An. Rpt. 10:103. 1897. 3. Britton and Brown 2:247, 1897.
It is impossible from present knowledge to say certainly whether the Miner-like plums put by Bailey into a botanical sub-division of Prunus hortulana are extreme variations of the species or, as Bailey in his last accounts and Waugh at all times have supposed, are hybrids between Prunus hortulana and Prunus americana. It is certain that all of these plums are intermediate in some characters between the two species named; neither botanists nor pomologists can agree as to whether certain varieties belong to the one or the other botanical division. There are, however, in several herbaria, specimens from the wild, and from different localities, that indicate that there is a distinct plum toward the northern limit of the range of Prunus hortulana which, if a natural hybrid, is of so ancient hybridity that the plants now come measurably true to type. The chief representatives of the Miner-like plums under cultivation, as Miner, Forest Rose, Prairie Flower and Clinton, are so like these wild plums as to lead the writer to believe that Bailey’s botanical sub-division is justified and is worth continuing even though a considerable number of the varieties now put with Miner, most of which have originated under cultivation, are hybrids and that the wild plums may have come from natural hybrids of more or less remote time.
The sub-species differs from the species in having shorter, stiffer, less graceful branches; leaves smaller, thicker, rougher and of a bluish-green cast; the blossoms of the two are much the same but those of the sub-species open a few days earlier; the fruits of the sub-species are larger than those of the species, lighter red, have more bloom, are less firm in texture, ripen earlier, yet later than those of any other species, and are quite different in flavor, having more nearly the taste of the fruit of Prunus americana; the stones, as well as the fruits, are very different, being in the sub-species larger, broader, flatter, smoother and less pointed. The differences in fruit and stone, and to some extent in the leaves, can be seen if the color-plates of Forest Rose and Wayland be compared.
In fruit-growing, the Miner-like plums behave in general much like the Americana plums. In some respects the fruits are an improvement upon those of the Americana varieties. For example the skin in the Miner-like varieties is usually less tough; is brighter in color and the flavor, in most cases, is a little better. These plums seem to be nearly or quite as hardy as the Americanas and are adapted to quite as wide a range of soils. Presumably they have the same value as stocks, though they seem not to have been tried for this purpose and they should have equal value at least in plant-breeding. The trees of the Miner-like plums are rather more amenable to domestication than those of Prunus americana having as orchard plants straighter trunks, more symmetrical and less unkempt tops and making larger trees. The fruits ripen so late as to make the varieties of this group especially valuable in prolonging the season for plums in regions where native varieties are grown exclusively. About twenty varieties of this sub-species are under cultivation.
12. PRUNUS NIGRA Aiton
PRUNUS NIGRA
1. Aiton Hort. Kew. 2:165. 1789. 2. Sims Bot. Mag. 1117. 1808. 3. Pursh Fl. Am. Sept. 1:331. 1814. 4. Torrey Fl. U. S. 1:469. 1824. 5. Sargent Silva N. Am. 4:15, Pl. 149. 1892. 6. Small Torrey Bot. Club Bul. 21:301. 1894.
Cerasus nigra. 7. Loiseleur Nouveau Duhamel 5:32. 1812.