190 TREES OF MINNESOTA. 



long-, 2-lobed; fruit described under family Salicaceae, ripening 

 before the full development of the leaves in May or June. A 

 g-enus of about twenty species of soft wooded trees mostly 

 natives of cold climates, one-half of which are found in 

 North America. 



Populus tremuloides. Aspen. American or Quaking- 

 Aspen. 



Leaves ovate or obicular with a sharp, short apex, small, 

 smooth on both sides; petiole long 1 , flattened. Flowers in 

 April before the leaves in hairy catkins. Fruit a small, 2- 

 valved capsule: seeds very small. Bark smooth, greenish 

 white except on very old trees; twig-s not angular. This is 

 generally a small, short-lived tree, but occasionally it grows 

 60 or more feet high. The pendulous leaves tremble in the 

 slightest breeze; the silver gray bark is attractive and the 

 autumn color of the leaves is one of the purest golden yellows 

 found among trees. 



Distribution. From southern Labrador to southern shores 

 of Hudson Bay, to the Mackenzie and Yukon Rivers, south 

 to Pennsylvania, Missouri, New Mexico and Lower Califor- 

 nia and through all mountain ranges of the west., One of the 

 most widely distributed trees of North America. In Minne- 

 sota it is found throughout the state and is very common on 

 cut-over timber lands, where it is generally the first tree to 

 take possession of the land after the pine is cut off. It grows 

 most luxuriantly along the borders of swamps and open 

 forest glades. The seed is carried long distances by the wind. 



Propagation. By seeds, which grow freely; but the seeds, 

 however, are seldom sown in nurseries as the limited demand 

 for this species is easily supplied by the seedlings which 

 spring up along the lake shores and sand bars. 



Properties of wood. Light, soft, not strong, close grained, 

 of cottony fiber and soon decays in contact with the soil. It 

 is of a light brown color with thick nearly white sapwood. 

 Specific gravity 0.4032: weight of a cubic foot 25.13 pounds. 



Uses On account of the color of the bark and the autumn 

 color of the leaves an occasional specimen of Aspen can be 

 used to advantage to give variety to our tree plantings. 



