34 THE AMERICAN BOTANIST. 



to the frozen wastes of arctic America, where it is reduced to a 

 small matted shrub a few inches in height. 



The grace and symmetry of their foliage add much to the 

 beauty of our winding streams and make them desirable trees 

 for planting where there is sufficient moisture in the soil to 

 insure their growth. Not less are they valuable for planting 

 along streams where the rapid current is likely to tear away 

 the banks. Their extensive root system binds together the 

 soil and in a measure checks the inroads of the stream. 



In attempting to identify the species of willow inhabiting 

 any particular region one must be constantly on the lookout 

 for hybrids, as many species hybridize freely with others. In 

 this respect they resemble the oaks but probably hybridization 

 is more frequent between tliem than between members of the 

 genus Qucrciis. Perhaps this may in a measure be accouted 

 for by the large amount of pollen produced by each staminate 

 tree or shrub, and the ease with which it is carried by the 

 Avind to the waiting pistillate blossoms of other individuals. 



The first willow that one beginning the study of the genus 

 would be sure to notice would be the shining willow (Salix 

 lucida) its beautiful shining leaves appearing as if coated with 

 varnish, making it a conspicuous tree wherever it grows. Un- 

 fortunately it is not common, at least in most localities. The 

 white willow {S. olba) is another noticeable tree, having its 

 leaves covered with a white, silky down. It is an introduced 

 species and said to hybridize with some of our native willows. 

 Another foreigner which has now made itself thoroughly at 

 home with us, is the crack willow {S. fragilis). This is a tall, 

 handsome tree which was planted at an early day in eastern 

 Massachusetts from whence it has widely spread. It no doubt 

 gets its name of crack willow from the ease with which the 

 twigs may be separated from the main stem ; only a slight 

 blow being sufficient to break them off. After a hard storm 

 in which the branches are threshed by the wind, the ground 



