Rehder says of P. ussuriensis,[15] “This species differs from the allied species chiefly in the short stalk of the globose fruit with persistent calyx, in the broad, often nearly orbicular, strongly setosely serrate leaves and in the lighter yellowish-brown branches; the flower clusters are, owing to the short stalks, rather dense and hemispherical, the petals are obovate and rather gradually narrowed toward the base; the styles are distinctly pilose near the base.”
Wilson,[16] describing the vegetation of Korea, says of this species: “Pyrus ussuriensis is abundant and this year is laden with fruit. On some trees the fruit is wholly green, on others reddish on one side; the length of the peduncle varies and the same is true of the leaf-structure; the calyx is persistent or deciduous often on fruits on the same branch.”
The habitat of this species is northern and northeastern China and eastern Siberia. Manchuria, Korea, Amurland, and Ussurri are named as regions in which it is most commonly found. A glance at the map shows that this habitat is in the far north for pears, and it might well be suspected that this would be one of the hardiest of all pears, and this proves to be the case. Horticultural varieties are reported by Chinese explorers, some of which have been introduced by the United States Department of Agriculture. These no doubt have some value in the most northern fruit regions of America and if not for their fruits, they may prove useful in hybridization. But it is as a possible stock resistant to blight that the species has received most attention in this country.
Reimer, of Oregon, found this species to be very resistant to fire-blight and at first thought it might prove to be a valuable stock. Following Reimer’s experiments much was said of it as a promising new stock, and the United States Department of Agriculture gave it a thorough trial from the results of which they discouraged its use. The tree proved to be a slow grower; very subject to leaf-blight, therefore unable to hold its leaves during the growing and budding season, difficult to use in budding as the tough bark did not “slip” easily, and but a small number of the buds took. According to Galloway,[17] however, the Kuan li or Chinese water pear, which he says belongs to the Ussuriensis group, is one of the most promising pear stocks. Both for its fruits and as a stock, this species is likely to receive much attention in the United States for some time to come. The difficulty at present, as we have found at this Station, is to get seeds or budding wood true to name of the forms of the species that seem to be most desirable.
6. PYRUS SERRULATA Rehder
1. P. serrulata Rehder Proc. Amer. Acad. Arts & Sci. 50:234. 1915.
Chinese Saw-leafed Pear. This species, according to Rehder, is closely related to P. serotina but differs from it chiefly in its serrulate, not setosely serrate, generally broader, leaves, in the smaller flowers with usually three or four styles, and in the shorter sepals and smaller fruit.
This pear was first found by E. H. Wilson in 1907 in western Hupeh. The province of Hupeh is 800 or 900 miles west and south of Shanghai. The pears in this location grow in thickets at an altitude of 4000 to 5000 feet. Reimer found the species at Ichang, in Hupeh, at elevations of 3000 to 3700 feet. Its occurrence at these altitudes indicates that it is a hardy form. Whether the species is likely to be valuable for its fruits, or for hybridization, does not appear, but Galloway,[17] reporting on it as tested by the United States Department of Agriculture, says that it is affected but slightly by leaf-blight, holds its foliage well in hot summers, and has a long budding season. These statements indicate that it is worth trying as a stock.
