* 
498 CXXV. BETULACEZ. Beruta, 
1, BETULA. Tourn. 
Betu is the Celtic name for the birch. — 
3d in a cylindrie ament; bracts deeply 3-parted, peltate; calyx 0; 
stamens 10—12. @ Ament oblong-ovoid; scales subtrilobate ; calyx 
0; nut compressed, with a membranaceous margin.— Tees and shrubs 
mostly with the outer bark laminated and horizontally fibrous. Lvs. 
ovate, serrate, alternate. 
* Trees. 
1. B. penta. Black Birch. Sweet Birch. Mahogany Birch. 
Las. cordate-ovate, acuminate, acutely serrate, veins beneath and petioles 
hairy; fertile aments erect—This noble species is common in the Eastern and 
Middle States, often exceeding 60f in height, with a diameter of 2to 3f. 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 4 as wide. Sterile aments 2—3/ long, fertile much 
shorter and thicker. In spring the cambium affords the boys a jicious morsel. 
The wood is of a reddish color, strong, compact, and takes a good polish. It 
is much used in cabinet work. April, May. 
2. B, excersa. Ait. Lofty or Yellow Birch. 
Lvs. 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 height of 60—80f, with a 
trunk 2—3f diam., invested with a thin, yellowish cuticle. Barren aments 2— 
4’ long, cylindric, clustered, and pendulous at the ends of the branches. The 
wood is chiefly valuable as fuel. April, May. 
3. B. nicra. Ait. (B. rubra. Michz.) Red Birch. 
Lws. rhombic-ovate, acute at each end, doubly serrate, glaucous beneath ; 
fertile ament sessile, erect, ovoid, scales villous, the segments linear, equal—A 
tree 30—50f high, growing on the banks of streams, Methuen, Mass., Emerson, 
to Car. W. to IJa.! and Ill., Mead. 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. Leaves dark 
green above, about 3’ by 2’, often smaller, petioles 6—8” long, pubescent. May, 
4. B. popuuirouia. Ait. Poplar-leaved Birch. White Birch. 
Lws. 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 1 the 
trunk is invested. It is common in the rocky and mountainous woods of N. 
England, where it seldom exceeds 30—40f in height. The branches are covered 
with a reddish-brown bark, very slender, and throw out, in May, long, pendu- 
lous aments. 
5. B. papyracea. Ait. Paper Birch. Canoe Birch. sad 
_ Lws. ovate, acuminate, doubly serrate, the veins hairy beneath; fertile 
aments nodding, pedunculate; lateral lobes of the calyx short, roundish.—This 
birch is abundant in the hillside woods of N. England, &c. It sometimes at- 
tains the height of 60—70f, but is generally smaller. The trunk, which is 1— 
2f in diameter, is covered with a tough cuticle consisting of numerous lamine, 
the outer of which is snow white. Of this the Indians construct their light 
canoes. The bark upon the branches is dark brown. Leaves 2—3/ long, 4 as 
wide. Sterile aments 1—2’ long. The wood is of a fine, compact texture, but 
not durable, and is used in turnery and furniture work. May, June. 
B. minor. Tuckerman. Lvs. smaller, ovate, glabrous, acute, some of them 
roundish-obtuse.—White Mts. Shrubs 6—9f high. 
* Shrubs. 
6. B. pumina. Dwarf Birch. “ 
Low, shrubby ; young branches pubescent, without glandular dots; dvs. or- 
bicular-obovate, petioles densely pubescent beneath ; fertile ament cylindrical. 
