Minnesota Plant Life. 



293 



a single carpel instead of five or more as in other roses. Thi> 

 single carpel, or pistil, at the centre of the flower, contains one 

 or two seed-rudiments and the fruit matures as a stone fruit. 

 The outer wall of the pistil becomes fleshy, while the inner grows 

 hard and produces the stone. Inside, the one or two seed- 

 rudiments mature into the kernels. Plums have a smooth or waxy 

 outer surface for their fruits, while peaches and apricots have 

 this surface downy. In almonds the fleshy tract does not de- 

 velop and the nuts may be described as peaches with dry pulp. 

 Of plums there are two principal varieties, 

 the plums proper and the cherries. In 

 Minnesota there are one or two species 

 of plum, including the very 

 common wild plum, a tree 

 ten to twenty feet in height, 

 with red, purplish or yellow 

 fruits. The stone is flat- 

 tened, with one edge sharp 

 and the other grooved. Be- 

 sides this common variety, 

 at the extreme northern 

 edge of the state are trees 

 of the Canada plum, aver- 

 aging somewhat larger than 

 the ordinary sort, with 

 broader leaves and larger, 

 longer fruits. In addition 

 to these two varieties of true 

 plums there are six sorts of 

 cherries. Almost the only 

 difference between the plums and the cherries is the flavor of 

 the fruit, though cherries as a class have rather more globular 

 fruits than plums. The Minnesota varieties are the dwarfed 

 or sand-cherry, common on sandy beaches, especially in the 

 northern part of the state ; the wedge-leafed cherry with fruits 

 four or five lines broad; the western sand-cherry, resembling 

 the wedge-leafed cherry in its foliage but with fruits nearly 

 twice as large, found on prairies in the western part of the state ; 

 the pin-cherries with sour small fruits, without bloom, with 



144. A cluster of choke-cherry 

 flowers and a single flower dis- 

 sected. After Atkinson. 



