Genus 3. 



BIRCH FAMILY. 



607 



In dry woods, Cape Breton Island to Manitoba, Nebraska, Florida and Texas. Wood similar 

 to that of the Hornbeam, but heavier ; weight per cubic foot 51 lbs. Bark scaly. April-May. Fruit 

 ripe July-Aug. Hard-hack. Indian-cedar or black-hazel. I-ever- or deer-wood. 



3. CORYLUS (Tourn.) L. Sp. PI. 998. 1753. 



Shrubs or smali»1:rees, with broad thin serrulate or incised leaves. Staminate aments 

 sessile at the end^if twigs of the previous season, expanding much before the leaves, the 

 flowers solitary' in the axil of each bract, of about 4 stamens and 2 bractlets; filaments 

 2-cleft or 2-divided, each fork bearing an anther-sac, which is villous at the summit. Calyx 

 none. Pistillate flowers from scaly buds, clustered at the ends of short branches of the 

 season, each in the axil of a bract, consisting of an incompletely 2-celled ovary adnate to a 

 calyx, a short style and 2 slender stigmas; bractlets 2, enlarged in fruit, forming a leaf-like 

 involucre to the nut, remaining nearly distinct or united into a tubular beak. Nut ovoid or 

 oblong, sometimes compressed, large, bony. [Name Greek, from the helmet-like involucre.] 



Species 7, in the northern hemisphere. Besides the following, another occurs in California. 

 Type species : Corylus Avellana L. 



Involucre of 2 broad laciniate bractlets ; leaves serrulate. 1. C. americana. 



Involucral bractlets united, prolonged into a tubular bristly beak. 2. C. rostrata. 



i. Corylus americana Walt. Hazel-nut. 

 Filbert. Fig. 1492. 



Corylus americana Walt. Fl. Car. 236. 1788. 



A shrub, 3°-8° tall, the young shoots russet- 

 brown, densely hispid-pubescent with pinkish hairs, 

 the twigs becoming glabrous. Leaves ovate or broadly 

 oval, acute or acuminate at the apex, serrulate all 

 around, cordate or obtuse at the base, glabrous or 

 nearly so above, finely tomentose beneath, 3'-6' long, 

 2'-$' wide; petioles 2"-^" long; staminate aments 

 mostly solitary, 3'-4' long; involucre of the nut com- 

 pressed, composed of the 2 nearly distinct finely pu- 

 bescent leaf-like bractlets, which are lacinate on their 

 margins, commonly broader than high and exceeding 

 ' the nut; nut compressed, light brown, striate, ¥ high. 



In thickets, Maine and Ontario to Saskatchewan, 

 Florida and. Kansas. March-April. Nuts ripe July-Aug. 



2. Corylus rostrata Ait. Beaked Hazel- 

 nut. Fig. 1493. 



Corylus rostrata Ait. Hort. Kew. 3: 364. 1789. 



A shrub, similar to the preceding species, but the 

 foliage usually less pubescent. Leaves ovate orjnar- 

 rowly oval, acuminate at the apex, cordate or obtuse 

 at the base, incised-serrate and serrulate, glabrous, or 

 with some scattered appressed hairs above; sparingly 

 pubescent at least on the veins beneath, 2F-4' long, 

 i'-2i' wide; petioles 2"-$" long; involucral bractlets 

 bristly hairy, united to the summit and prolonged into 

 a tubular beak about twice the length of the nut, lacin- 

 iate at the summit; nut ovoid, scarcely compressed, 

 striate, 5"-7" high. 



In thickets, Nova Scotia to British Columbia, south to 

 Georgia, Tennessee, Kansas and Oregon. April-May. 

 Fruit ripe Aug.-Sept. 



4. BETULA (Tourn.) L. Sp. PI. 982. 1753. 



Aromatic trees or shrubs, with dentate or serrate leaves, scaly buds and flowers of both 

 kinds in aments expanding before or with the leaves, the pistillate erect or spreading. Stam- 

 inate flowers about 3 together in the axil of each bract, consisting of a membranous, usually 

 4-toothed perianth, 2' stamens, and subtended by 2 bractlets; filaments short, deeply 2-cleft, 

 each fork bearing an anther-sac. Pistillate flowers 2 or 3 (rarely 1) in the axil of each bract, 

 the bracts 3-lobed, or sometimes entire, deciduous with the fruits ; perianth none ; ovary ses- 



