648 • Order 120.— BETULACE^. 



dulous; buds rather acute. — A small tree dissenfliaated throughout flie U. S. 

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

 visions. Leaves about twice as long as wide. The I'ruit is similar in appearance 

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

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

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



6. CARPrWUS, L. Hornbeam. (Celtic car, wood, and pino, the 

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

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

 bearded at summit. $ Flowers in«, loose ament ; scale large, oblong, 3- 

 lobod, 1 — 3-flowered ; cal. 6-toothed ; stig. 2; nut long, ovoid, fur- 

 rowed, 1-seeded. — ^Small trees. Scales of the $ aments persistent and 

 becoming foliaceous. 



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

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

 lateral tooth. — A small tree (12 — 2 Of high), common in woods throughout the U. 

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

 or ash-colored bark. Leaves 2 — 4' long, J 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. 



. Ordeb CXX. BETULACE^. Biechworts. 



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

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

 ceoious, amentaceous, mostly naked, 3 in the axil of a 3-lobed bract. S Stamens 

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

 l-celled and 1-seeded (by abortion) membranous and Indehiscent. Seed pendulous, 

 without albumen. Kgs. 11, 90, 106, 111, 419, 420. 



Genera 2, species G5, chiefly natives of the cool parts of tha northern hemisphere. Properties 

 generally astringent. The birches are often line timber trees. 



1. BE'TULA, Tourn. Birch. (jBc^m 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 0; 

 ovaries 8 under each scale ; stigmas 2, filiform ; nut compressed, with 

 a membranous margin. — Trees and shrubs, with the outer bark 1am- 

 iilated 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, 9 aments No. 1 



* Trees with a reclrlish-l>rown bark and oviite-oblong, auberect, ? aments Noa* 2,8 



* Trees with a white bark, long-stalked leaves and drooping 9 aments Nos. ,4# 5 



* Shrubs with brownish bark, roundish leaves and short, erect, ¥ aments Nos. 6,7 



1 B. exoelsa Ait. Yellow Biech. Lvs. ovate-elliptic, subacuminate ; sub- 

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

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

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

 to the height of 60 to 80f; with a trunk 2 to Bf in diam., invested witli » thin, 

 yellowish, silvery outer bark Stripping off in transverse shreds. 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 Biboh. Sweet Biroh. Mahogany Bieoii. (Pig. 202.) 

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

 and petioles hauy; fertile aments erect, oval-oblong, thick, obtuse, pedtmn^te; 

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

 mon in the Eastern and Middle States, often exceeding 60f in height,, with a- 



