648 ORDER 120. BETULACE^L 



dulous; buds rather acute. A small tree disseminated throughout the U. S., 

 25 30f in height. Its bark is remarkable for its fine, narrow, longitudinal di- 

 visions. Leaves about twice as long as wide. The fruit is similar in appearance 

 to hops, suspended from the ends of the branches, consisting of membranous, im- 

 bricated sacs (cups?) containing each a flower. The wood is very white, hard 

 and strong, much used for levers, &c. Apr., May. 



6. CARPrNUS, L. HORNBEAM. (Celtic car, wood, and pino, the 

 head ; alluding to its use in making yokes for cattle.) $ Flowers in a 

 long, cylindric ament ; cal. scale roundish, clliate; sta. 8 14, slightly 

 bearded at summit. ? Flowers in a loose amcnt ; scale large, oblong, 8- 

 lobed. 1 3-flowered ; cal. G-toothed ; stig. 2; nut long, ovoid, fur- 

 rowed, 1 -seeded." Small trees. Scales of the $ aments persistent anu 

 becoming foliaceous. 



C- Americana L. Lvs. oblong-ovate, acuminate, unequally Ben-ate ; scales of the 

 fertile ament 3-parted, the middle segment much the largest, oblique, with 1 a 

 lateral tooth. A small tree (12 20f high), common in woods throughout the U. 

 S. The wood is very fine-grained, compact and white, covered with a light gray 

 or ash-colored bark. Leaves 2 4' long, as wide, petiolate. From the ends of 

 the branches hang the long, loose, pale green, leafy aments, consisting of alter- 

 nate pairs of enlarged scales, with a dark-colored nut at the base of each. Apr., 

 May. 



ORDER CXX. BETULACE^ BIRCHWORTS. 



Trees or shrubs with deciduous stipules. Bark separating into thin layers. Leaves 

 alternate, simple, with the veinlcts running straight to the margin. Flowers mon- 

 oecious, amentaceous, mostly naked, 3 in the axil of a 3-lobed bract. $ Stamens 

 definite, distinct. Anthers 2celled. S Ovary 2-celled, 2-ovuled, becoming in fruit 

 1 -celled and 1-seeded (by abortion) membranous and indehiscent, S^ed pendulous, 

 without albumen. Figs. 77, 00, 10G, 111, 419, 420. 



Genera 2, specie* Go, chiefly natives of the cool parts of the northern hemisphere. Properties 

 1,'enerally astringent. The birches arc often fine timber trees. 



1. BETULA, Tourn. BIRCH. (JSetit is the Celtic name for the birch.) 

 $ Flowers in a cylindric ament ; bracts deeply 3-parted, peltate ; calyx 

 a scale ; stamens 4. ? Ament oblong-ovoid, scales trilobate ; calyx ; 

 ovaries 3 under each scale; stigmas 2, filiform ; nut compressed, with 

 a membranous margin. Trees and shrubs, with the outer bark lam- 

 inated and horizontally fibrous, the inner aromatic. Branchlets dot- 

 ted. Lvs. ovate, serrate. Figs. 419, 420. 



* Trees with a yellowish bark, smoothish leaves, and short, erect, $ aments No. 1 



* Trees \vithareddUh-bro\vn bark mid ovate-oblontr, sitberect, s aments Nos. 2, 3 



* Trees with a white bark, long-stalked leaves and drooping ? aments Nos. 4, 5 



* Shrubs with brownish bark, roundish leaves and short, erect, ? uuiciite Nos. 6, 7 



1 B. excelsa Ait. YELLOW BIRCH. Lvs. ovate -elliptic, subacuminate ; sub- 

 cordate, coarsely, sharply, and doubly Ferrate, smooth when old, on short, downy 

 petioles; fertile amenta' erect, ovoid-oblong; lobes of the bracts subequal, acute, 

 diverging. A common forest tree, N. Eng. to Mich, and Can., arising in woods 

 to the height of 60 to 80f, with a trunk 2 to 3f in diam., invested with a thin, 

 yellowish, silvery outer bark stripping off in transverse shrede. Barren aments 

 2 to 4' long, cylindric, clustered, and pendulous at the ends of the branches ; 

 fertile 1' long, 6" diam. Apr., May. 



2 B. lenta L. BLACK BIRCH. SWEET BtRcn. MAHOGANY Bmcm (Fig. 202.) 

 Lvs. cordate-ovate^ acuminate, acutely, finely, and doubly serrate, veins beneath 

 and petioles hairy ; fertile aments erect, oval-oblong, thick, obtuse, pedunculate', 

 scales hairy, the lobes obtuse, subequal, diverging. This noble species is com- 

 mon in the Eastern and Middle trtatos, odea exceeding 60i' ia height, with u 



