BETULACEAE. 



5. Betula lenta L,. 



Cherry, Black or Sweet Birch. (Fig. 1215.) 

 Bet ii la lenta L. Sp. PI. 983. 1753. 



A large forest tree, sometimes 80 high, with dark 

 brown close smooth bark, becoming furrowed, not 

 separating in layers; foliage aromatic; twigs smooth, 

 warty, young leaves silky. Mature leaves ovate or 

 ovate-oblong, acute or acuminate, the base cordate 

 or rounded, sharply serrulate, bright green, and 

 shining above, dull green and pubescent on the 

 veins beneath, 2^ / -4 / long, \'-2 r wide; petioles 

 3"_6" long; staminate aments clustered, 2%'-$' 

 long; pistillate aments sessile, dense, oblong, about 

 i' long and ]/%' in diameter in fruit, nearly erect; 

 bracts glabrous or minutely puberulent, appressed, 

 about 2" long, nearly equally 3-lobed, the lateral 

 lobes somewhat divergent; nut oblong, broader 

 than its wings. 



Newfoundland to western Ontario, Florida and Ten- 

 nessee. Wood hard, strong, dark brown; weight per 

 cubit foot 47 Ibs. The aromatic oil of the branches and 

 foliage (same as oil of wintergreen) is distilled in 

 quantities and is an important article of commerce. Tree much resembles the cherry. April-May 



6. Betula lutea Michx. f. Yellow Birch. 



Betula lutea Michx. f. Arb. Am. 2: 152. pi. 5. 1812. 



A large forest tree, similar to the preceding species, 

 reaching a maximum height of about 100 and a trunk 

 diameter of 4, the bark yellowish or gray, separating 

 in thin layers or close, the twigs gray-brown. Leaves 

 ovate or oblong-ovate, mostly acuminate at the apex, 

 rounded, obtuse or rarely subcordate at the base, 

 sharply serrulate all around, dark green and dull 

 aboye, pubescent on the veins beneath, \y*'-\' long, 

 petioles 4 // -o/ / long; staminate aments usually 2-4 

 together; pistillate aments sessile, oblong or oblong- 

 cylindric, \ l /z f or less long, y // -9 // thick in fruit, 

 rather loose; bracts nearly equally 3-lobed to the 

 middle, ciliolate, the lateral lobes ascending; nut 

 broadly oblong, wider than its wings. 



Newfoundland to Manitoba, south to North Carolina 

 and Tennessee, mainly in the Alleghanies. Wood hard, 

 strong, light brown ; weight per cubic foot 41 Ibs. April- 

 May. 



Gray Birch. (Fig. 1216.) 



2 



7. Betula glandulosa Michx. Glandular 

 or Scrub Birch. (Fig. 1217.) 



Betula glandzilosa Michx. Fl. Bor. Am. 2: 180. 1803. 



A shrub, i-4 high, the twigs brown, glandular- 

 warty, not pubescent. Leaves orbicular, oval or ob- 

 ovate, glabrous, rounded at the apex; rounded, nar- 

 rowed or cuneate at the base, crenate-dentate, bright 

 green above, pale green and glandular-dotted beneath, 

 short-petioled, #'-i' long; petioles \"-$" long; 

 staminate aments commonly solitary, about ^' long; 

 pistillate aments cylindric, erect, peduncled, $"-12" 

 long and about 2" in diameter iu fruit; fruiting bracts 

 glabrous, the lateral lobes divergent, rather shorter 

 than the middle one; nut oblong, usually narrower 

 than its wings. 



Newfoundland to Alaska, the higher mountain- "f 

 Maine and northern New York, Michigan, Minnesotaand 

 in the Rocky Mountains to Colorado. Also in Asia. 

 June-July. 



