Alnus — Alder. 237 



ica. These appear in the middle and northern portions of 

 the United States and Canada, but seldom or never within 

 or near the tropics. They constitute an interesting group 

 of small trees or tall shrubs, though attracting compara- 

 tively little attention. When growing along the edges of 

 streams they often do a valuable service in protecting 

 the banks from washing by floods or being carried away 

 by constant attrition. They are said to be largely planted 

 for this purpose on the dykes and banks of canals in Holland 

 and other low countries where such protection is needed. 

 They are all the better adapted to this use from the fact 

 that the roots do not extend far, but grow in a compact 

 and knotted mass, throwing up a multitude of suckers 

 near the original stem. 



The wood is orange-yellow, soft, but exceedingly dur- 

 able under water, and in Europe, whenever of sufficient 

 size, is in demand for spikes and posts. It furnishes excel- 

 lent charcoal for the manufacture of gunpowder, for which 

 it has long been employed. The bark is in use for tan- 

 ning and dyeing, and produces a reddish color if used 

 alone, and with the addition of copperas, a jet black. 

 The flowers are in terminal, imbricated clusters, the male 

 and female in separate catkins on the same branch ; the 

 fertile ones being hard and compact, while the others are 

 loose and open, both hanging long on the branches. The 

 leaves are ovate, slightly lobed, with a blunt point at the 

 extremity, and are smooth and somewhat glossy, often 

 with white dots or scales. The flowers appear early, the 

 ament having been formed in autumn, and so far advanced 

 as to be in readiness for the first warm breath of spring. 



