BETULACEiE. 346 ALXCS. 



2. B. populifo'lia. 



Leaves deltoid, long-acuminate, unequally serrate, very smooth, on smooth 

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

 This species, like the preceding, is distinguished for the white cuticle with 

 which the trunk is invested. It is common in the rocky and mountainous 

 woods of N. England, where it seldom exceeds 30 — 40 feet in hight. The 

 branches are covered with a reddish brown bark, very slender, and throw out, 

 in May, long, pendulous aments. Common White Birch. 



3. B. exce'lsa. 



Leaves ovate, acute, serrate, on pubescent petioles, shorter than the pedun- 

 cles ; barren aments ovate, erect; scales with rounded lateral lobes. A 

 common forest tree in N. England, arising in woods to the hight of 60 — 80 

 feet, with a trunk 2 — 3 feet in diameter, invested with a thin, yellowish cuticle. 

 Barren aments 2 — 4 inches long, cylindric, clustered, and pendulous at the 

 ends of the branches. The wood is chiefly valuable as fuel. YelUno Birch. 



4. B. LENTA. 



iea»ej' cordate-ovate, acuminate, acutely serrate, nerves beneath and petioles 

 hairy ; fertile amoits erect. This noble species is common in the Eastern and 

 Middle States, often exceeding 60 feet in hight, with a diameter of 2 — 3 feet. 

 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 inches long, about ^ as wide. Sterile aments 2 — 3 

 inches long; fertile, much shorter and thicker. In spring the cambium 

 affords the boys a delicious morsel. The wood is of a reddish color, strong, 

 compact, and takes a good polish. It is much used in cabinet-work. April. 

 May. Black Birch. Maliogany Birch. 



* * Shrubs. 



5. B. GLANDULO'SA. 



Low; irant//e5 glandular-punctate, smooth or pubescent; leaves oho\^^.e , 

 serrate, very entire at base, smooth, subsessile ; feriile ament oblong ; scales 

 half 3-cleft ; lobes ovate-oblong, middle one rather longest; 7;7/i orbicular, 

 with a narrow margin. A shrub, inhabiting the mountainous districts of the 

 Northern States. Hight 3 — 5 feet. Leaves scarcely an inch in length, 

 varying in width. Scrub Birch. 



p.pumila; branches pubescent; leaves orbicular-ovate, petiolate, densely 

 pubescent beneath ; fertile aments cylindric. 



6. B. NANA. 



Low, smooth ; leaves orbicular, crenate, reticulated beneath ; scales of th$ 

 ament deeply 3-parted ; seeds orbicular, nearly wingless. This miniature tree 

 is found on the summits of Mt. Clinton, Mt. Franklin, &c , of the White 

 Mts. It is scarcely more than a foot in hight, often but a few inches, the 

 branches few and straggling, the leaves i — | inch in diameter, smooth both 

 sides, pale and distinctly reticulate beneath, and on petioles 1 — 2 lines long. 

 May, June. Dicarf Birch. 



2. ALNUS. 



Skrilejl. — Ament long, cylindric, composed of cuneate, 

 truncate, 3-lobed, o-flowered bracts; calyx 4-parted ; stamens 

 4. Feriile fl. — Ament ovoid ; bracts 2-tlovvered ; 3-fid ; caljx 

 ; nut wingless, compressed. 



The old Latin name for these shrubs. 



