Betula. BETULACE^. 199 



1. BETULA. Tourn.; Endl. gen. 1840 ; Spach in ann. sc. nat. 1841, p. 193. birch. 



\, Derived from balu, the Celtic name for the Birch.] 



Sterile fl. Bracts with two bracteoles. Calyx consisting of a single scale. Anthers one- 

 celled. Fertile fl. Bracts 3-lobed, deciduous, 3-flowered. Nut lenticular, winged on 

 each side. — Trees or shrubs. Fertile aments lateral, solitary. 



1. Betula populifolia, Ait. (Plate CXII.) White Birch, 



Leaves deltoid, much acuminated, unequally serrate, smooth on both sides ; fertile aments 

 on long peduncles, pendulous, cylindrical ; lateral lobes of the bracts oblong, decurved- 

 falcate. — Ait. Kew. (ed. 1.) 3. p. 336 ; Michx. sylv. t.-7\ ; Pursh, fl. 2. p. 620 ; Bigel. 

 fl. Bost. p. 355 ; Torr. compend. p. 355 (bis) ; Beck, hot. p. 325 ; Hook. fl. Bor.-Am. 2. 

 p. 155. B. alba, var. populifolia, Spach, I. c. 



A tree 20 - 25 feet high and seldom more than six inches in diameter, with numerous 

 slender branches, and a thin white epidermis which cannot easily be split into laminae. The 

 leaves are 2-3 inches long, somewhat cordate at the base, conspicuously acuminate, smooth 

 and shining : petiole about half an inch long. Sterile and fertile aments pedunculate ; the 

 latter at first erect, but at length mostly pendulous. Bracts with the lateral lobes a little curved 

 backwards, minutely pubescent. Wings of the nut very thin and membranaceous, broader 

 than the disk. 



In poor soils, both in wet and in dry situations. FL April. Fr. August. The wood of 

 this species is soft and white, speedily decaying when exposed to the weather, and unfit even 

 for fuel. ■ 



2. Betula pap yr ace a. Ait. Canoe Birch. Paper Birch. 



Leaves ovate, acuminate, somewhat doubly serrate, hairy on the veins underneath ; fertile 

 aments on short peduncles, pendulous, cylindrical ; lateral lobes of the bracts short and 

 rounded. — Ait. Kew. (ed. 1.) 3. p. 331 ; Michx. sylv. 1. t. 69 ; Pursh, fl. 2. p. 621 ; Bigel. 

 fl. Bost. p. 355 ; To7T. compend. p. 355 (bis); Hook, fl. Bor.-Am. 2. p. 155. B. papyri- 

 fera, Michx. fl. 2. p 180. B. alba, var. papyracea, Spach, I. c. 



A tree 40 - 70 feet high and 1-3 feet in diameter, with numerous slender shining branches 

 which are dotted with white ; the epidermis of the bark is white externally, thick, and divisible 

 into numerous thin layers of a reddish tinge internally. Leaves 2 - 2\ inches long, slightly 

 cordate, of a dark green color : petioles one-third of an inch long, smooth. Fertile aments 

 an inch or more in length, and 4-5 lines in diameter. Bracts slightly pubescent ; the lateral 

 lobes much shorter than the middle one, scarcely diverging. 



Woods in the northern parts of the State, abundant ; also on the Catskill mountains, but 

 scarce. Fl. April - May. Fr. Early in August. The wood of this species is excellent 

 fuel. It has a close shining grain, and possesses considerable strength, but it is liable to 

 rapid decay when exposed to the weather. Sometimes it is employed for making common 

 furniture. The bark is used by the northern Indians for making their canoes. 



