188 TREES OF MINNESOTA. 



silky, appearing before the leaves. A very hardy tree or 

 shrub of graceful habit attaining a height of 20 feet. More 

 difficult to propagate than most willows and occasionally 

 blights severely. 



Salix purpurea pendula. ( S. napoleonis. ) Napoleon 

 Willow. 



Leaves 1| to 2 inches long, linear, finely serrate, green 

 and shining above, dull bluish green beneath; petioles short. 

 Young twigs and petioles reddish. A spreading shrub but 

 when top-worked on an upright stock forms a very pretty tree 



Fig. 40. Napoleon Willow top-worked 

 on White Willow. 



with spreading pendulous branches. Hardy at the Minnesota 

 Experiment Station. Known among nurserymen as New 

 American Willow, but often worked on too tender stocks. 



Genus POPULUS. 



Leaves alternate, broad, more or less heart-shaped or 

 ovate.. Flowers dioecious. Individual trees bearing stami- 

 nateand pistillatecatkins and alsocatkins having the two kinds 

 of flowers mixed together occasionally occur. Flowers appear 

 before the leaves in long, drooping, lateral, cylindrical cat- 

 kins, the scales of which are furnished with a fringed margin; 

 the calyx is represented by an oblique cup-shaped disk with en- 

 tire margin; stamens usually numerous: ovary short; stigmas 



