Obdeb 120.— BETULACE^S. 649 



diameter of 2 to 3 f. The trunk is invested with a dark brown or reddish bark, 

 which becomes rough in old trees, and is remarkable for its agreeably aromatic 

 fragrance and flavor. Leaves 3 — 4' long, about h as wide. Sterile amenta 2 — 3' 

 long, fertile much shorter and thicker. In spring the cambium affords the boys a 

 delicious morseL Wood reddish, strong, compact Apr., May. 



3 B. nigra Ait Red Birch. Lvs. rhombic-ovate, acute at each end, doubly ser- 

 rate, or obscurely 9 to \Z-lobed, glaucous beneath ; fertile ament sessile, erect, ovoid, 

 scales villous, the segments linear, equal — A tree 30 to 50f high, growing on 

 banks of streams and in river swamps, Mass., 11L and Fla. (!) Trunk covered 

 with a reddish or chocolate-colored bark which at length becomes very loose and 

 torn, hanging in shreds, and finally rough like that of the black cherry. Branches 

 arched and slender ; branchlets almost filiform, often clothing the trunk to the 

 base. Lvs. dark green above, about 3' by 2' often smaller, petioles 6 to 8" long, 

 pubescent. May. (B. rubra Mx.) 



4 B. populifolia Ait. Poplar-leaved Birch. "WmTE Birch. (Fig. 10G.) Lvs. 

 deltoid, long-acuminate, unequally serrate or obscurely many-lobed, very smooth, on 

 smooth petioles ; fertile aments pedunculate; scales with roundish, lateral lobes. 

 — Like the next, distinguished for the white cuticle with which the trunk is in- 

 vested. It is common in the rocky and mountainous*woods of N. Eng., where it 

 seldom exceeds 30 to 40f in height The branches are covered with a reddish- 

 brown bark, very slender, and throw out in May, long, pendulous aments. 



5 B. papyracea Ait Paper Birch. Canoe Bmcn. Lvs. ovale, acuminate, 

 doubly serrate, the veins hairy beneath; fertile aments nodding, pedunculate; 

 lateral lobes of the calyx short, roundish. — This birch is abundant in the hillsido 

 woods of N. Eng. to Wis. and Can. It sometimes attains tho height of GO — 70f, 

 but is generally smaller. Trunk 1 — 2f diam., covered with a tough cuticle con- 

 sisting of numerous lamina?, the outer of which is snow white. Of this tho In- 

 dians construct their light canoes. Branches dark brown. Leaves 2 — 3' long, £ 

 as wide. Sterile aments 1 — 2' long. The wood is of a fine, compact texture, 

 easily wrought May, Jn. 



}3. MiN'OR. Lvs. smaller, ovate, glabrous, acute, some of them roundish-obtuse 

 —White Mts. Shrubs G— 9f high. 



6 B. pumila L. Dwarf Birch Shrub erects its ascending branches glandular- 

 punctate, glabrous ; lvs. olovate, entira at base, obtusely serrate, glabrous ; fertilo 

 ament cylindrical, about as long as the leaves ; scales half 'S-cleft, lobes ovate- 

 obloBg, middle one rather longest; nut orbicular, conspicuously margined. — A 

 beautiful shrub inhabiting the mountainous districts of N. and N. W. States, N. 

 to Hudson's Bay. Height 2 to Cf. Lvs. about 9'' by 6 or 7", very regularly 

 toothed. Aments of both kind3 7 to 9". (B. glandulosa Mx.) 



7. B nana L. Tixy Birch, Shrub, low, trailing, smooth ; lvs. orbicular, crenaie, 

 reticulated beneath; scales of the $ ament deeply Z-parted; seeds orbicular, nearly 

 wingless. — This miniature tree is found on tho summits of Mt Clinton, Mt. Frank- 

 lin, &o, of the White Mts. It is scarcely more than a foot in height, often but a 

 few inches, the branches few and straggling, the lvs. i to §' diam., smooth both 

 sides pale and distinctly reticulate beneath, and on petioles 1 to 2" long. (B. Littel- 

 iana Tuckerman.) 



3. AL'NUS, Tourn, Alder. (The ancient Latin name from Celtic 

 ■<rf, near, 7a??, the river bant.) $ Aments cylindrie, drooping, the 

 bracts with 5 bractiolcs beneath; calyx 4-parted; stamens 4, anthers 

 2-celled. ? Aments ovoid, bracts cuneate, truncate, fleshy, 2-fiowered; 

 ■calyx of 4 scales adnate below to the bracts, all persistent and woody 

 in fruit ; fruit compressed, wingless or winged. Shrubs arising from 

 large and strong roots. Buds pedunculate, Lvs, plicate in vernation, 

 ? Aments panicled, (Fig. 111.) 



§ Fruit wingless, Nos. 1, 2. £§ Fruit broadly winged. (Axxaster, Spaci.) Ko. 3. 



2 A. incana Willd. Speckled Alder. Elack Alder, Lvs. submembranous, 

 oblong, acutish, -obtuse at late cr cordate, margin fcomewhat lobed, sharply ser- 

 rate, glaucous-pubescent beneath; vem3 hirsute, their axils naked; siip. ollong- 



