132 



Salicace.^.. — Willow Family. 



Populus balsaiiiifera, L. Balsam Poplar. 



In the deep, wooded ravines of the Minnesota valley; 

 rare. It is reported also from near Sioux Falls, but no 

 specimens have been seen.* 

 Populus ang-ustifolia, James. Narrow-leaved Cotton- 

 wood. 



In the Black Hills. 



Populus acuiniiiata, Rydberg. Black Cottonwood. 

 Near Hot Springs in the Black Hills. 



Populus tremuloides, Michx. American Aspen. 



On the dry bluffs and in the spring swamps in the 

 Minnesota valley, in the higher altitudes in the Black 

 Hills, and in isolated patches between the Missouri river 

 and the Black Hills. It is reported also from the Sioux 

 valley, but no specimens have been seen. 



Populus (leltoides, Marsh. Cottonwood. 



Around lakes and bordering streams throughout the 

 state; common. 



Salix nig-ra, Marsh. Black Willow. 



A shrub or small tree, common along streams in the 

 Minnesota, Sioux and James valleys. 



Salix liuviatilis, Nutt. Sand-bar Willow. 

 Salix longifolia^ Gray. 



A small, slender shrub, along streams and lakes 

 throughout the state; the commonest of the willows. 



Salix Bebbiana, Sarg. Bebb's Willow. 

 Salix rostrata^ Richards. 



In the Minnesota valley and in the Black Hills. 



Salix humilis, Marsh. Prairie Willow. 



Common in the Minnesota region; it is usually found 

 on the wooded bluffs or the edge of the open prairie, 

 acting as the advance guard of the wooded formations. 



♦Williams, Bulletin 43, U, S. Exp. Sta., S. D.; 105; 1S95. 



