BETULA 



consisting of 3 connate bracts: fr. a minute nut, often 

 erroneously called seed, with membranous wings, 

 dropping at maturity with the 3-pointed scales from the 

 slender rachis of the strobile. About 35 species in N. 

 Amer., Eu., N. and Cent. Asia, especially in the northern 

 regions. No tree goes farther north than the birch, in 

 N. Amer. B. papyrifera reaches 60 north latitude, 

 and in Eu. B. pubescens goes to the N. Cape, and is still 

 n forest tree at 70. Monogr. by Regel: Monographische 

 Bf'urbeitung der Betulacea; (1861); and in DeCandolle, 

 1'rodmmus, 16, 2, p. 162 (1869); and by VVinkler in 

 Engler's Pflanzenreich : Betulacesc, p. 56, quoted below 

 as U. B. 



The birches are often conspicuous on account of their 

 colored bark, and slender usually pendulous stamiriate 

 catkins before the leaves and much smaller pistillate 

 catkins, followed by subglobose to cylindric strobiles. 

 The hard and tough wood is often used in the manu- 

 facture of furniture and of many small articles, in 

 making charcoal, and for fuel; from the bark, boxes, bas- 

 kets, and many small articles are made; also canoes 

 from that of the B. papyrifera; in Russia and Siberia it 

 is used in tanning leather. The sap of some species is 

 used ;is a beverage. The birches are very ornamental 

 park trees, hardy, except two or three Himalayan spe- 

 cies, and especially valuable for colder climates. They 

 MIC i-ssentially northern trees and are short-lived in 

 warmer regions, particularly mountain species like B. 

 lutea, while B. nigra and B. lenta are better suited for 

 a warmer climate than most other species. Their 

 foliage is rarely attacked by insects, and turns to a 

 bright or orange-yellow in fall. Their graceful habit, 

 the slender, often pendulous branches, and the pictur- 

 esque trunks make them conspicuous features of the 

 landscape. Especially remarkable are those with white 

 bark, as B. papyrifera, B. populifolia, B. pendula, 

 B. Ermanii, and also B. Maximowiczii with yellow 

 bark. 



Most birches prefer moist, sandy and loamy soil; 

 but some, as B. pendula and B. populifolia, grow as 

 satisfactorily in dry localities and poor soil as in swamps 

 and bogs, and they are especially valuable in replant- 

 ing deserted grounds as nurses for other trees; both are 

 comparatively short-lived trees. 



Propagation is readily accomplished by seeds, gath- 

 ered at maturity and sown in fall, or usually kept dry 

 during the winter, or stratified; but B. nigra, which 

 ripens its fruits in June, must be sown at once, and by 

 fall the seedlings will be several inches high. The seeds 

 should be sown in sandy soil, rather thick, as the per- 

 centage of perfect seeds is not very large, slightly or 

 not at all covered, but pressed firmly into the ground 

 and kept moist and shady. The seedlings must be 

 transplanted when one year old. Rarer species and 

 varieties are grafted, usually on B. lenta, B. papyrifera, 

 B. nigra or B. pendula. Cleft or tongue-grafting in early 

 spring, on potted stock in the greenhouse, is the best 

 method. Budding in summer is also sometimes prac- 

 tised. Shrubby forms may also be increased by layers, 

 and B. nana by greenwood cuttings under glass. 



INDEX. 



BETULA 



497 



32 



A. Veins of Ivs. 7 pairs or more, usually impressed above. 



Trees. 



B. Lvs. large, 4-6 in. long, deeply cordate: cones cylin- 

 drical, racemose, 2-4- 



1. Maximdwiczii, Regel. Tree, 80-90 ft., with 

 smooth, orange-colored trunk and dark reddish brown 

 branchlets: Ivs. long-petioled, broadly ovate, coarsely 

 and doubly serrate, membranous, pubescent on 

 younger trees, nearly glabrous on older ones: cones 

 K-3 in. long, slender, nodding; fr. with very broad 

 wings. Japan. B.M. 8337. S.I.F. 1:23. W.B. 90. 

 This is probably the most beautiful of all birches, per- 

 fectly hardy N. and of rapid growth; its large foliage 

 and the yellow color of the trunk render it a highly 

 ornamental and conspicuous park tree. 



BB. Lvs. 2-5 in. long: cones solitary: wings narrower 

 than the fr. 



c. Under side of Ivs. glaucescenl: Ivs. rhombic-ovate, cu- 

 neate at base with 7-fi slightly impressed pairs 

 of veins. 



2. nigra, Linn. (B. rubra, Michx.). RED or RIVER 

 BIRCH. Tree 50-90 ft. : bark reddish brown, or silvery 

 gray on younger branches, separa- 

 ting into numerous thin, papery 



flakes: branchlets pubescent: 

 petioles scarcely J^in. long: Ivs. 

 rhombic-ovate, acute, doubly ser- 

 rate, pubescent when 

 young, at length only 

 on the veins beneath, 

 pale or glaucescent 

 beneath, 2-3 % in. 

 long: cones 1-1% in. 

 long, cylindrical, 

 ripening in May or 

 June; scales pubes- ; 

 cent, with erect, 

 linear-oblong, nearly 

 equal lobes. From 

 Mass, south to Fla. 

 and west to Kan. and 

 Minn. S.S. 9:452. 

 L.B.C. 13:1248. G. 

 F. 2:591. Gn. 55, p. 

 161 (habit). W. B. 

 63. H.T. 122, 123. 

 A moisture-loving, graceful tree, with slender, very 

 numerous branches, and remarkable for its torn and 

 ragged bark. 



cc. Under side of Ivs. light green: Ivs. rounded or truncate 



at the base, with 8-14 pairs of impressed veins. 

 D. Shape of Ivs. ovate or oblong-ovate, rounded and often 

 cordate at the base, broadest about the middle; 

 veins distinctly impressed above: petioles less than 

 %in. long. See page 3566. 



E. Cones peduncled, cylindric. 



3. fitilis, Don (B. Bhojpdttra, Wall.) Tree, 40-60 

 ft.: trunk with reddish brown bark: branchlets pubes- 

 cent while young, not glandular: Ivs. ovate, rounded at 

 the base, acuminate, densely irregularly serrate, pubes- 

 cent on the veins beneath, 2-3 in. long, with 8-12 pairs 

 of veins: cones peduncled, cylindrical, 1-2 in. long, 

 with erect oblong lobes, the middle one much longer. 

 Himalaya. Japan. S.I.F. 1:23. Not quite hardy N. 



EE. Cones sessile or nearly sessile, ovoid or ovoid-oblong. 



4. lenta, Linn. (B. carpinifdlia, Ehrh.). CHERRY, 

 .SWEET, or BLACK BIRCH. Tree, 60-70 ft.: trunk dark 

 reddish brown, young bark aromatic, of agreeable 

 flavor: Ivs. oblong-ovate, usually cordate at the base, 

 sharply and doubly serrate, hairy beneath when young, 

 nearly glabrous at length, 2-5 in. long: cones ovoid- 

 oblong, 1-1 J^ in. long; scales about fin. long, lobed 



547. Cone of Betula lutea. 

 (Cone natural size.) 



