BETULACE^E. (BIRCH FAMILY.) 411 



leaves often spicy-aromatic. Foliage mostly thin and light. Buds sessile, scaly. 

 Sterile catkins long and drooping, terminal and lateral, formed in summer, re- 

 maining naked through the succeeding winter, and expanding their golden 

 flowers in early spring, preceding the leaves: fertile catkins ohlong or cylindri- 

 cal, lateral, protected hy scales through the winter, and developed with the 

 lea\es. (The ancient Latin name.) 



# Trees, with the bark of the trunk white externally, separable in thin sheets : petioles 



slender : fertile catkins cylindrical, peduncled, spreading or drooping. 



1. B. :all>a, var. populifolia, Spach. (AMERICAN WHITE BIRCH.) 

 Leaves triangular (deltoid), very taper-pointed, truncate or nearly so at the broad 

 base, smooth and shining both nidi .s- (glandular-dotted when young). (B. populi- 

 folia, Ait.) Common on poor soils, Penn. to Maine, near the coast. A small 

 and slender, very graceful tree, with chalky-white hark, much less si-parable 

 into sheets than the next species ; the very long-pointed leaves on petioles of 

 fully half their length, tremulous as those of an Aspen. (Eu.) 



2. B. papyracca, Ait. (PAPER BIRCH. CANOE BIRCH.) Leaves 

 ovate, taper-pointed, heart-shaped or ahrnpt (or rarely wedge-shaped) at the base, 

 smooth above, dull underneath; lateral lobes of the fruit-bearing bracts short and 

 rounded. Woods, New England to Wisconsin, almost entirely northward, and 

 extending far north. A large tree, with fine-grained wood, and very tough 

 durable bark splitting into paper-like layers. Leaves dark-green above, pale, 

 glandular-dotted, and a little hairy on the veins underneath, sharply and une- 

 qually doubly serrate, 3-4 times the length of the petiole. There is a dwarf 

 mountain variety. 



# * Trees, witJi reddish-brown or yellowish bark : petioles short : fertile catkins ovoid- 



oblong, scarcely peduncled. 



3. B. nlgra, L. (RIVER or RED BIUCH.) Leaves rhombic-ovate, acutish 

 at both ends, whitish and (until old) downy underneath; fertile catkins ohlong, 

 somewhat peduncled, woolly; the bracts with oblong-linear nearly equal lobes. 

 (B. rubra, Michx. f.) Low river-banks, Massachusetts to Virginia and south- 

 ward. A rather large tree, with reddish-brown bark and compact light-colored 

 wood: leaves somewhat Alder-like, glandular-dotted, sharply doubly serrate. 



4. B. excelsa, Ait. (YELLOW BIRCH.) Leaves ovate or elliptical, point- 



ed, narrowed (but mostly heart-shaped) at the base, sinoothis/t, unequally serrate 

 with coarse and very sharp teeth ; fruiting catkins oroid-oblong, slightly huinj ; lobes 

 of the scales tnarly equal, acute, slightly diverging. Moist woods, Xew England 

 to Lake Superior, and northward. Tree 40 -60 high, with yellowish silvery 

 bark, thin leaves : twigs less aromatic than in the next ; the wood less valuable. 



5. B. leiita, L. (CHERRY BIRCH. SWEET or BLACK BIRCH.) Leave.s 

 heart-orate, pointed, ?harplv and finely doubly sen-ate, hair*/ on t/ reins Ix-math ; 

 fruiting catkins dliptical, thick, smncir/iaf. hairy; lobes of the. re in if scales nearly 

 equal, obtuse., din rging. Moist rich woods. New England to Ohio and north- 

 ward, and southward in the mountains. A rather lar^e tree, with dark chest- 

 nut-brown bark, reddish bron/.e-colored on the spray, much like that of the 

 Garden Cherry, which the leaves also somewhat resemble; the twi^s and folia^a 

 Bpicy-aromatie : timber rose-coiored, line-grained, valuable tor cabinet-work, 



