CLASS XXI. ORDER VIII. 381 



392. BETULA. 

 Betula papyracea. Mx.f. Canoe Birch. 



Leaves oval, acuminate, subequally serrate ; petioles 

 glabrous; veins hairy beneath. Mx.f. 



This tree, which is called also Large ichite hirch and Paper 

 birch, alfords a great portion of the eastern ivood consnmed as 

 fuel in this city. It is abundant in the northern and eastern 

 parts of New England. Leaves ovate, much less acuminate 

 than those of the following species. Fertile aments nodding. 

 The trunk is covered with a tough, white cuticle of many layers, 

 from which the Indians manufacture their canoes. The wood is 

 hard, close grained, and used in furniture. 

 Betula populifolia. Ait. Common White Birch. 



Leaves extensively acuminate, unequally serrate, 

 glabrous. Mich.f. 



The name of white birch is indiscriminately applied to this 

 species, and to Betula papyracea. The present species is com- 

 mon here in swamps, and multiplies very fast in moist lands 

 that are not properly cleared. Like the paper birch, its trunk is 

 covered with a white, smooth, outer bark, separable into thin 

 layers, and very inflammable. Its young twigs are flexible, of 

 a dark brown, spotted with vifhite. The leaves are heart shaped, 

 tapering to a long point, glutinous, smooth on both sides. The 

 flowers, both barren and fertile, are in long, pendulous aments. 

 The wood is white, soft, and very perishable, decaying sooner 

 than the bark. 

 Betula nana. L. Dwarf Birch. 



Low, smooth; leaves orbicular, crenate, reticulated 

 underneath ; scales of the ament deeply three parted, 

 seeds orbicular, nearly wingless. 



A very small, alpine species, found on the summit of the 

 "White mountains. 

 Betula lenta. L. Black Birch. Mahogany Birch. 



Leaves heart-ovate, acutely serrate, acuminate, 

 glabrous. Mich.f. 



