206 CORYLACEAE 



branched at the tips; anther-sacs separate, pilose above. Pistillate aments 

 terminal, solitary; bracts subtending two flowers, developing into bladdery 

 sacks. Calyx denticulate. Nut ovoid, flattened, obscurely ribbed. 



1. O. virginiana (Mill.) K. Koch. A tree 6-18 m. high; twigs Ught green and 

 pubescent at first; leaf -blades ovate or oblong-lanceolate, acuminate at the apex, 

 sharply serrate, 7-1.5 cm. long; staminate aments 3-7 cm. long; bractlets tri- 

 angular-ovate, acuminate; pistillate aments about 8 mm., in fruit 4-6 cm. long; 

 nut 5-8 mm. long, shining. Dry woods: N.S. — Fla. — Tex. — (Black Hills) S.D. 

 Submo7it. Ap-My. 



2. CORYLUS (Tourn.) L. Hazelnut. 



Shrubs or trees, with branched stem and smooth bark. Staminate aments 

 pendulous, very long, solitaiy or in clusters; bracts enclosing 4-8 stamens; fila- 

 ments short, forked at the apex; anther-sacs separate, pilose at the apex. Pis- 

 tillate aments inconspicuous, clustered at the tips of the branches; each bract 

 enclosing 2 bractlets and an incompletely 2-celled ovary. Nut large, enclosed 

 in a leafy involucre formed by the more or less united bracts. 



Twigs glabrous or nearly so; beak of the involucre fully twice as long as the nut, strongly 

 ribbed. 1. C. roslrata. 



Twigs decidedly hirsute, sometimes somewhat glandular; beak of involucre not more 

 than half longer than the nut, not strongly ribbed. 2. O. californica. 



1. C. rootrata Ait. A shrub 1-2 m. high, with brown branches; leaf-blades 

 ovate or oval, sharply serrate, glabrous or with scattered hairs above, sparingly 

 pubescent especially on the veins beneath, 5-12 cm. long; involucral bracts 

 bristly hairy, united and prolonged into a tubular beak, laciniate at the summit; 

 nut ovoid, scarcely compre.ssed, striate. Beaked Hazlenut. Thickets: N.S. 

 — Ga. — Colo. — N.b. Submont. Ap-My. 



2. C. californica (A. DC.) Rose. A shrub, or small tree, up to 12 m. high, 

 with brown pubescei^t branches; leaf-blades broadly ovate to suborbicular, 

 2.5-7 cm. long, cordate or rounded at the base, double-toothed, rough and 

 pubescent above, soft-pubescent and paler beneath; involucral bracts bristly 

 hairy, united into a tube, cleft at the apex; nut rounded-ovoid, 1.5 cm. in di- 

 ameter. Woods: Calif. — B.C. Son. — Submont. 



Family 34. ULMACEAE. Elm Family. 



Monoecious, polygamous, or hermaphrodite trees or shrubs, with simple 

 leaves, often 2-ranked and oblique at the base. Flowers in cymes or racemes. 

 Calyx of 3-8 sepals, more or less united at the base, imbricate. Stamens of 

 the same number, opposite the sepals. Pistil of 2 united carpels; ovary 

 2-celled. Fruit a samara, drupe, or nut. Endosperm scant or wanting. 



Fruit a samara; embryo straight. 1. Ulmus. 



Fruit a drupe; embryo with conduplicate cotyledons. 2. Celtis. 



1. ULMUS (Tourn.) L. Elm. 



Trees or shrubs, with furrowed, often corky bark. Leaves 2-ranked, oblique, 

 straight-veined, serrate, deciduous. Flowers perfect, in axillary clusters. Calyx 

 membranous, 4-9-lobed, usually 5-lobed, campanulate. Stamens exscrtcd; fila- 

 ments filiform or slightly flattened; anthers extrorse. emarginate at both ends. 

 Ovary sessile or short-stalked, l-ccUed or rarely 2-celled; stigmas often incurved, 

 introrse. Samaras orbicular or oblong, winged all around. Seeds flattened. 



1. U. americana L. A large tree, sometimes 35 m. high, with glabrous or 

 sparingly pubescent twigs; leaves oval or obovate, abruptly acuminate at the 

 apex, obtuse or acutish at the oblique base, sharply, usually doubly serrate, 

 slightly rough above, pubescent or glabratc beneath, 5-12 cm. long; samara 

 ovate-oval, reticulate-veined, 10-12 nun. long, glabrous except the ciliate mar- 

 gins. American oh White Elm. Moist soil: Newf. — Fla. — Tex. — se Mont. — 

 Sask. PlaiJi — -Submont. Mr-Ap. 



