326 FLORA. 



Order 8. FAGALES. 



Trees or shrubs, with small monoecious or rarely dioecious flowers 

 in aments, or the pistillate ones subtended by an involucre, which be- 

 comes a bur or cup in fruit. Calyx usually present. Corolla none. 

 Endosperm none. 



Both staminate and pistillate flowers in aments. Fam. i. Betulaceae. 



Pistillate flowers subtended by an involucre, which becomes a bur or a cup in fruit. 



Fam. 2. Fagaceae. 



Family x. BETULACEAE Agardh. 



Birch Family. 



Monoecious or rarely dioecious trees or shrubs, with alternate petioled 

 simple leaves, and small flowers in aments. Stipules mostly fugacious. 

 Staminate aments pendulous. Staminate flowers 1-3 together in the axil 

 of each bract, consisting of a membranous 2-4-parted calyx or none, and 

 2-10 stamens inserted on the receptacle, their filaments distinct, their 

 anthers 2-celled, the anther-sacs sometimes distinct and borne on the 

 forks of the 2-cleft filaments. Pistillate aments spike-like or capitate. 

 Pistillate flowers with or without a calyx adnate to the solitary 1-2-celled 

 ovary ; style 2-cleft or 2-divided ; ovules 1-2 in each cavity of the ovary, 

 anatropous, pendulous. Fruit a small, mostly i-celled and i-seeded nut 

 or samara. Testa membranous. Endosperm none. Cotyledons fleshy. 

 Radicle short. Six genera and about 75 species, mostly natives of the 

 northern hemisphere. 



Staminate flowers solitary in the axil of each bract, destitute of a calyx ; pistillate flowers 

 with a calyx. 



Staminate flowers with no bractlets ; pistillate aments spike-like ; nut small, sub- 

 tended by or enclosed in a large bractlet. 



Fruiting bractlet flat, 3-cleft and incised. 1. Carpinus. 



Fruiting bractlet bladder-like, closed, membranous. 2. Ostrya. 



Staminate flowers with 2 bractlets ; pistillate flowers 2-4, capitate ; nut large, enclosed 

 by a leafy involucre. 3. Cory/us. 



Staminate flowers 3-6 together in the axil of each bract, with a calyx ; pistillate flowers 

 without a calyx. 



Stamens 2 ; filaments 2-cleft, each fork bearing an anther-sac ; fruiting bracts 3-lobed 



or entire, deciduous. 4. Betula. 



Stamens 4 ; anther-sacs adnate; fruiting bracts woody, erose or 5-toothed, persistent. 



5. Alnus. 



1. CARPINUS L. 



Trees or shrubs, with smooth gray bark, furrowed and ridged stems, and 

 straight-veined leaves, the primary veins terminating in the larger teeth. Aments 

 expanding before the leaves. Staminate aments linear-cylindric, sessile at the 

 ends of short lateral branches of the preceding season, their flowers consisting of 

 3-12 stamens; filaments short, 2-cleft, each fork bearing an anther-sac. Pistillate 

 flowers in small terminal aments, 2 to each bract, consisting of a 2-celled ovary 

 adnate to a calyx and subtended by a flat persistent bractlet, which becomes 

 much enlarged, foliaceous and lobed or incised in fruit, the bracts deciduous; stigmas 

 2, subulate. Nut small, ovoid, acute, borne at the base of the large bractlet. [The 

 ancient name.] About 12 species, natives of the northern hemisphere, only the 

 following American. 



1. Carpinus Caroliniana Walt. American Hornbeam. Blue Beech. 

 Water Beech. (I. F. f. 1207.) A small tree, with slender terete gray twigs. 

 Leaves ovate-oblong, acute or acuminate, sharply and doubly serrate, rounded or 

 suhcordate at the base, somewhat inequilateral, 0.6-1 dm. long, slightly pubes- 

 cent on the veins beneath; petioles very slender; staminate aments 2-3 cm. long, 

 their bracts triangular-ovate, puberuknt; bractlet of the pistillate flowers 3-lobed 



