REPORT OF THE HORTICULTURIST. 103 



SESSIONAL PAPER No. 16 



The epecies found in eastern C: iiada is Primus nigra, Ait., the type of which is 

 distinguished easily at a glance from P. americana, Marsh, in being darker in the 

 bark and with a much stiffer and more upright habit than the latter. The fruit of P. 

 nigra ripens, as a rule, earlier than that of P. americana, and is usually more evenly 

 covered with red. Some varieties are good in quality, but, as a rule, ai*e not as high 

 flavoured as those of americana. This species, however, .varies consid'Crably and 

 sometimes it is difficult to decide whether a variety is P. nigra or P. americana. The 

 trees bear heavily and regularly, but if they are not kept thoroughly sprayed the fruit 

 becomes affected with plum blight, and withers and falls before becoming ripe. The 

 spfcies called P. americana is not known to occur in Canada, although the form of 

 wild plum growing in Manitoba is much like it, but is intermediate in some character- 

 istics between the two. Its range is from New Jersey to Montana. The named 

 varieties wdiich have sprung fiom this species comprise most of the best kinds now 

 offered for sale. This tree growls from 10 to 20 feet in height, is of spreading habit 

 and is usually quite hardy where the native species grows. It bears heavily and 

 regularly, as a rule, and the fruit of the best varieties is of good size and attractive 

 appearance, and, although not equal in quality to the best European plums, is juicy, 

 sweet, often high flavoured, and at all times refreshing. The skin is sometimes more or 

 less acrid, but this is not apparent when eating some of the best varieties, although 

 when canned or preserved, it sometimes develops, though often it does not. P. 

 americana does not suffer from blight to any extent, and this is an important reason 

 why varieties of it should be planted instead of P. nigra, unless the trees are properly 

 sprayed. 



The following technical descriptions of the two species, made by Waugh, give 

 their distinguishing characteristics in greater detail and accuracy : — 



'P. americana, Marsh. — Common Wild Plum. The type distinguished by entire 

 calyx lobes, which are pubescent on the inner surface; stone turgid; leaves oval or 

 slightly obovate; petioles mostly without glands. Tree spreading, ragged, thorny, 

 8 to 20 feet high ; flowers large, white, on slender pedicels ; leaves very coarsely 

 veined, never glossy or shining; fruit more or less flattened upon the sides, firm and 

 meaty, the skin tough and glaucous and never glossy, ripening through yellow to red. 

 Occurs wild from New Jersey and New York to Montana and Colorado. It varies 

 southward, in Texas and New Mexico represented mostly by the variety mollis. 



' Var. nigra. Canada Plum, Red Plum (P. nigra. Ait., P. americana T. & G. and 

 6th ed. Gray's Manual.) In its extreme forms easily distinguished by the glandular- 

 serrate calyx lobes, glabrous on the inner surface; compressed stone; broadly oblong- 

 ovate to obovate leaves with petioles bearing two glands. Flowers large, white, with 

 short thick peduncles conspicuously marked by the scars left by the falling of the bud 

 scales; pedicels dark red, slender, glabrous; calyx tube broadly obconic, dark red on 

 the outer and bright red on the inner surface ; fruit oblong-oval, orange-red ; stone 

 nearly oval, compressed. Occurs wild from Newfoundland west to Kainy and Assini- 

 boine rivers in Canada, and commonly in the New England States, where it is found 

 along roadsides and in waste places.' 



The plum has been well studied by Prof. F. A. Waugh, of Burlington, Vt., and 

 through his work the fact has been established that practically all varieties of Ameri- 

 can plums are self-sterile. In other words, there would be no fruit in an orchard 

 containing- a number of trees of one variety only, unless the wind or insects carried 

 pollen of other varieties to fertilize the flowers. This knowledge is of great impor- 

 tance to the fruit grower. It is another indication that ' nature abhors perpetual 

 self-fertilization.' While a variety is self -sterile in itself, if it is fertilized by 

 another self-sterile variety, fruit will be formed, and vice versa. It is necessary, 

 then, if good crops are to be obtaipad, to have more than one variety growing in the 

 orchard, to have the varieties bloom at the same time, and to have them of the same 

 species, if possible ; and, failing that, to have the species as closely related as possib' \ 



