246 TREES OF MINNESOTA. 



mon throughout most of the state on rocky banks or hillsides. 



Propagation. Described under genus. 



Properties of wood. The heaviest Minnesota wood. Specific 

 gravity, 0.8618. Otherwise about the same as C. tomentosa. 



Uses. The White Thorn is used for similar purposes in 

 ornamental planting as the others mentioned but is not so 

 desirable. 



Genus PRUNUS. 



Shrubs or trees with alternate, simple leaves. Flowers 

 with calyx that is deciduous after flowering; a single pistil 

 with a superior ovary containing a pair of ovules and becom- 

 ing a single drupe or stone fruit. This genus comprises some 

 of our most valued fruits, such as the Plum, Peach, Cherry, 

 Apricot and Nectarine and ornamental plants such as the 

 Double Flowering Almond; all the species here referred to are 

 ornamental when in flower. 



This genus seems to divide more or less into two groups 

 which are distinguished by the form of inflorescence, one 

 group bearing its flowers in racemes and the other in umbels. 

 It is of interest to notice that it is difficult if not quite impos- 

 sible to graft or bud trees of the different groups together 

 while within each group trees of the different species can be 

 grafted quite readily. 



Prunus americana. Wild Plum. 



Leaves oval or slightly obovate. Flowers appear when 

 the leaves are about one-half unfolded. Fruit large, colored 

 with red and yellow often with a heavy bloom; generally 

 ascerb but frequently good: the parent of our cultivated sorts 

 such as Kollingstone, Wolf, Forest Garden, Desoto, Cheney 

 and others; ripens August to September. A small thorny 

 tree seldom over twenty feet high and generally found grow- 

 ing in thickets. A form of this that flowers very early and 

 has fruit with a thin .pit is considered a variety or perhaps a 

 separate species ( P. nigra. ) The Aitkin plum comes under 

 this head. 



Distribution. It is found from New York and New Jersey 

 to Nebraska and the upper Missouri Valley south to northern 



