Trees of New York State 165 



BETULAGEAE 



Betula nigra L. 



River Birch, Red Birch, Black Birch 



Habit — A tree 30-60 feet in height wdth a short trunk usually dividing near 

 the base into several large, obliquely ascending limbs which form in age a 

 round-topped, open, irregular crowTi. Under optimum conditions some- 

 times 80-100 feet in height with a bole 4-5 feet through, at other times 

 a bushy tree branching from the ground. 



Leaves — Alternate, rhombic-ovate, l*/^-3 inches long, 1-2 inches mde, acute 

 at the apex, cuneate at the bnse, doubly serrate, at maturity thin but firm 

 in texture, dark green, smooth, and lustrous above, pale yello-vvish green 

 and glabrous or slightly pubescent below, borne on slender, pubescent 

 petioles about % of an inch long. Stipules pale green, ovate, fugacious. 



Flowers — Appearing in March and April before the leaves, monoecious, borne 

 in aments. Staminate aments preformed the preceding season, clustered, 

 subterminal. cylindrical, at anthesis brownish yellow, 2-3 inches long. Pis- 

 tillate aments appearing as the buds unfold, terminal and solitary on 

 short, 2-leaved lateral branches, bright green, cylindrical, pedunculate, 

 about % of an inch long. Flowers borne in clusters of 3. The staminate 

 flowers consist of 4 yellow half-anthers raised on short, bifurcated fila- 

 ments accompanied by a cah-x of 1 sepal and covered distally by a peltate, 

 broadly oval bract and 2 bracteoles. Pistillate flowers consisting of a 

 small, green, ovoid ovary surmounted by 2 spreading filiform styles, the 

 cluster of 3 subtended by an oblong, obtuse bract and 2 bracteoles. 



Fruit — • An erect, pedimculate, pubescent, pale bro^vn, ovoid-cylindrical, woody 

 strobile, 1-1^/^ inches long and about ^2 inch wide, consisting of imbri- 

 cated, 3-lobed bracts wMch are pubescent on the back and subtend winged 

 nutlets, both deciduous in mid-summer from the slender rachis. ISTiitlets 

 compressed, broadly oval, chestnut-brown, about Vs of an inch long, 

 cro^\Tied by the 2 persistent styles, with lateral, marginal, pubescent wings 

 narrower than the nutlet. 



Winter characters — Twigs slender, lenticellate, smooth, reddish brown and 

 lustrous, at length darker, the bark exfoliating in thin, papery scales. 

 Buds ovate, acute, smooth or somewhat hairy, divergent, covered by 3-7 

 chestnut-brown scales. Staminate aments clustered, subterminal, cylin- 

 drical, %-l inch long. Bark on limbs and upper part of bole light red- 

 dish brown to crnnamon red. exfoliating in papery, clinging scales, giving 

 the trunk a ragged appearance. Mature bark at the base of the trunk 

 dark reddish brown and fissured. 



Habitat — A moisture-loving species typically found along the banks of 

 streams, ponds, and lakes, more rarely on drier sites. 



Range — Central New England, south to Florida, west to Minnesota and 

 Texas. Zones A, B, and C. 



Uses — Wood light, medium hard, strong, close-grained, light bro^%Ti with 

 wide, pale sapwood. Used in the manufacture of cheap furniture and 

 woodenware. The tree is attractive ornamentalh" and is grown in parks, 

 cemeteries and private estates. 



