HandbO(.)k of Trees of the ^oetheen States and Canada. 123 



Tliis interesting tree occasionally attains 

 the height of SO or 90 ft. with trunk 4 to .5 

 ft. in diameter, \\1ieu isohited it develops a 

 narrow oblong head of nuinj' small branches, 

 but with age a fuller, rounder and usually 

 irregular picturesque head. The bark of 

 branches is smooth at first, of a lustrous red- 

 dish brown color, but with age breaks and 

 separates into successive layers which curl up 

 and long persist as thin papery scales of 

 various tints of red and bro\Nn. The.se form a 

 veritable mat on the larger liuil)s and trunks 

 of medium size, w'hile the bark of old trunks 

 becomes rough with thick irregular plate-like 

 scales. It inhabits the banks of streams sub- 

 ject to frequent inundation, and here its grace- 

 ful branches hanging over the waters and al- 

 most toucliing their surface with long sprays 

 of handsome foliage add greatly to their charm. 

 Prof. Sargent has called attention to the fact 

 that the early ri|)ening of the seeds of this 

 and other riparian trees greatly assures their 

 germination and growth, as they fall on the 

 banks at the season of low water, germinate 

 and make substantial growth when a later 

 seed would have found only water in which to 

 perish. 



The wood of the River Birch, of which a 



cubic foot when dry weighs 35.91 lbs., is used 



in the manufacture of wooden ware, etc' 



Leaves rhombic-ovate, acute, 2-4 in. lonf:, wide 

 cuneate or almost truncate and entire at base, 

 serrate and serrately-lobed or doubly serrate, pale 

 tomentose at first but flnall.v lustrous darl< green 

 above and tomentose on midribs and veins be- 

 neath : petioles slender, tomentose ; branchlets the 

 first season tomi'ntosi-. Floiprrs: staminate 

 aments 1 in. or less long in winter with rounded 

 lustrous scales finally 2-.'! in. long: pistillate 

 aments about Vo in. long with pubescent ciliato 

 scales. Fndt ripening in May or .Tune in cylindri- 

 cal strobiles 1-11/, in. long, with short tomentose 

 peduncles and scales with :'. about equal narrow 

 lobes : nutlet oval and about as wide as the ciliate 

 wings. 



»v 



1. A. W. 



IV, 



"^k 



.ii 



