CXXV. BETULACEiE. 497 



larger than the roundish nut, its border dilated and coarsely serrate.— Shrub 

 5— 6f high, growing in thickets and borders of fields, U. S. Leaves 3 — G' long 

 and § as wide. From the ends of the branches hang the long, pendulous 

 aments of barren flowers in April. The nuts arc remarkably distinguished by 

 the large, bell-shaped involucre in which each one is enveloped. They are a 

 well-tiavored fruit, though somewhat inferior to the European hazel or JUbert. 



2. C. RosTu.vrA. Ait. Beaked Hazel. 



Lvs. oblong-ovate, acuminate; stip. linear-lanceolate; invol. campanu- 

 late-tubular, longer than the nut, 2-parted, with dentate segments.— This 

 species is found in the same localities as the former, is a rather smaller .shrub, 

 and chiefly differs Irom it in the involucre, which is covered wi»h short, stiff" 

 hairs, and contracted at the top into a long (1— H') narrow neck, like a bottle. 

 Nuts as in C. Americana. May. 



5. OSTRYA. 

 Gr. ocTTpcov, a scale; in allusion to the conspicuous sacs (not scales) of the fertile aments. 



(^ in a cylindric ament ; cal. scale roundish-ovate, ciliate, 1 -flower- 

 ed ; anth. conspicuously bearded at the summit. 9 geminate, in a 

 loose, linear ament ; cal. ; fls. enclosed each in an inflated mem- 

 branous sac, which, at length, enlarged, contains the matured nut. — 

 Small trees. 



O. ViRGTNic.\. Hop Hornbeavi. Iron-vwod. Lever-wood. 



Lvs. ovate, acuminate, serrate; fertile ament oblong, pendulous; tntds 

 rather acute.— A small tree disseminated throughout the U. S., 25 — 30f in height. 

 Its bark is remarkable for its fine, narrow, longitudinal divisions. 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, imbricated sacs, 

 (cups 1) containing each a flower. The wood is very white, hard and strong, 

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



6. CARPINUS. 



Celtic car, wood, and pino, the head ; alluding to its use in making yokes for cattle. 



cJ^ in a long, cylindric ament ; cal. scale roundish, ciliate ; sta. 

 8 — 14, slightly bearded at summit. 9 in a loose ament ; scale large, 

 oblong, 3-lobed, 1 — 3-flowered ; cal. 6-toothed ; stig. 2 ; nut long, 

 ovoid, furrowed, 1 -seeded. — Small trees. Scales of the 9 aments per- 

 sistent and becoming foliaceous 



C. Americana. Hornbeam. 



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 — 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 alternate 

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



Order CXXV. BETULACE^.— Birchworts. 



Trees ox shrubs, with deciduous stipules. 



Lvs. alternate, simple, with the veinlets running straight from the midvein to the margin. 



Fls. monoecious, amentiiccoiis, mostly achlamydeous, ternate in the axil of a 3-lobed bract. 



Perianth wanting or of several small scales, sometimes resembling a real calyx. 



Sterile.— Sta. definite, distinct. Anth. 2-relled. 



Fertile.— Ova. 2-celled, Sovuled. Styles or stig-mas 2, distinct. 



Fr. 1-celled and 1 seeded (by abortion), membranous and indehiscent. 



Seed pendulous, without albumen. 



Genera 2, ? species 6.i, chiefly natives of the cool parts of the northern hemisphere. Properties gene- 

 raUi' astringent. The birches are often fine timber trees. 



GcJiera. 



\ 10—1-2. Scales of the fertile aments 3-flowered Betula. 1 



stamens M. Scales of the fertile amenta 2-flowere(l Alnus. 2 



