400 BOTANY OF CROP PLANTS 



to Domesticas. The species grows wild from the Mediterra- 

 nean northward into Norway, Sweden and Russia. Insititia 

 plums fall into four groups as follows: 



1. Damsons. — These are spicy plums, mostly sour, and 

 much desired for preserving. 



2. Bullaces. — This group contains a few varieties differing 

 but Kttle from the preceding group, except as to fruit shape. 

 The Bullaces are spherical. 



3. Mirabelles. — These are round, yellowish or golden plums 

 with a free stone and resemble much the green gages as to 

 quality. 



4. St. Juliens. — This is a name appUed to a group of plums 

 resembling the Damsons. They were formerly used in this 

 country as stocks. 



Prunus cerasifera. — These are the cherry or Myrobalan plums. They are 

 hardy, thrifty varieties, free from disease, readily adaptable and most suitable 

 for hybridizing. The trees are small, bloom profusely, and bear a small, 

 round, cherry-like plum from J^ to i inch in diameter. They are adapted 

 to ornamental usage. They are also used as stocks upon which to bud 

 other plums. 



Prunus triflora. — These are the Japanese plums; they are not cultivated 

 in many parts of the world. They are native of China. It is a highly adapt- 

 able group, vigorous, productive, early-bearing, and disease-free. Varieties 

 are, for the most part, cling stones. 



Prunus americana. — This is our most important native plum. It grows 

 wild from New Mexico to Manitoba, and eastward to the Atlantic Coast. 

 Not being able to raise European plums in the Mississippi Valley, Americans 

 domesticated the native American plum. Varieties of this species are hardy. 

 The American plum tree is usually small, with rough, shaggy bark. The 

 fruit is reddish or yellowish. Altogether, there are about 260 varieties of 

 the americana. Waugh finds that they often bear defective pistils or 

 stamens, or that they are often protandrous or protogynous. From his 

 observations, he recommends some provisions for cross-fertilization when 

 planting americanas. 



Prunus hortulana. — This species includes a number of plums well suited 

 for jelly, preserves, and spicing. They are very free of suckers. Important 

 varieties are American, Golden, Juicy, Ruby, Waugh, and Gonzales. The 

 Hortiilanas are adapted to the Southern States. 



