252 STATE HORTICULTUKAL SOCIETY. 



W. Kerb of Maryland, has produced such a hybrid, and the so-called 

 Blackman plum appears to be another. 



20. Some varieties of native plums, notably Wild Goose and Miner, are 

 not fertile with themselves, and this fact has undoubtedly retarded the 

 progress of native plum culture. This infertility is due to comparative 

 impotency of pollen iipon flowers of the same variety rather than to any 

 structural imperfection in the flowers themselves. 



21. This infertility is avoided by mixed planting, by means of which 

 foreign pollen is supplied to the impotent varieties. Care should be taken 

 to associate varieties which bloom at the same time, and with this precau- 

 tion the ordinary mixed or alternate planting, at usual distances, appears 

 to be successful. 



22. The best stocks for native plums are probably seedlings of the same 

 species, although they grow well, as a rule, upon related species, and even 

 upon the peach in some instances. Perhaps the most popular stock at 

 present is the Marianna, because of its habit of growing readily from cut- 

 tings, and so far it appears to have given satisfaction. The Chickasaw 

 and Hortulana types succeed well upon the peach. Chickasaw stocks 

 sprout so badly that they are in disfavor. In the north, Americana stocks 

 are popular for all the varieties which succeed there. 



28. As to the best varieties, there is a great difference of opinion. In 

 the northernmost states the Americana class is most reliable, although 

 some of the Hortulanas succeed. For the south the Chickasaws are 

 numerous and popular. The Hortulanas occupy an intermediate position. 



24. The native plums are in most regions comparatively free from insect 

 abuses. Although there are no curculio-proof plums, the curculio does 

 less damage to the native varieties than to the common or Domestica types. 



25. Among diseases, a mysterious blight and the peach-rosette are 

 prominent in the south. A fruit-scab and fruit-spot also occur. The 

 septoria or shot-hole fungus — which causes the serious shedding of leaves 

 in the Domestica plums — does little damage upon the natives. The black- 

 knot, brown fruit-rot, and plum-pockets are other diseases which the 

 grower will be likely to meet. 



26. As a whole, the native plum industry has made astonishing progress 

 and it has already assumed large proportions. It is certain to occupy a 

 large place in future American horticulture. 



II. CHERRIES. 



27. Eight and perhaps ten species of fiative cherries are in cultivation. 

 Of these, three are grown for fruit, and all but one or two are cultivated 

 for ornament. None of the species have gained much prominence under 

 cultivation, however. Most of them are of comparatively recent 

 introduction. 



28. The so-called dwarf or sand cherries are much confused, and two, 

 perhaps three species, are passing as Primus pumila. (a) The true P. 

 pumila, or sand cherry, is a low straggling shrub, growing along rivers 

 and coasts from Maine to Pennsylvania and Manitoba. It has long thick 

 leaves, and produces cherries of variable size, color, and (quality. Some of 

 these varieties give great promise as garden fruits, and they are already 

 under test at experiment stations. The plant is also being tested as a stock 

 for dwarf cherries, (b) P. cuneata is a slender upright shrub with larger 

 flowers and shorter obtuse spatulate or obovate thin leaves growing in 



