14 BETULACEAE. 



1. CARPINUS [Tourn.] L. Trees or shrubs, the bark smooth. Stami- 

 uate aments solitary, the bracts acute, ciliate. Pistillate aments with 3-lobed 

 bracts at maturity. 



1. C, caroliniana Walt. Tree becoming 13 m. tall or shrub, the bark blue- 

 gray: leaf -blades oblong, varying mainly to ovate or ovate-lanceolate, 3-14 

 cm. long, glabrous above: staminate aments 2-5 cm. long: mature bracts of 

 the pistillate aments hastate, 2-3 cm. long: nuts 5-6 mm. long. — Spr. 



The Hornbeam grows in rich woods and hammocks in northern Florida and in 

 the northern iiart of the peninsula. The brown heart-wood is close-grained, heavy, 

 and hard. (Cont.) 



2. OSTRYA [Mich.] Scop. Shrubs or trees, the bark scaly. Staminate 

 aments clustered, the bracts blunt, not ciliate. Pistillate aments with lobeless 

 bracts. 



1. O. virginiana (Mill. )Willd. Tree becoming 18 m. tall or shrub, the bark 

 rough: leaf-blades mainly oblong, elliptic, or oval, 3-13 cm. long, slightly 

 pubescent or glabrate above: staminate aments 3-8 cm. long: mature bracts 

 of the pistillate aments oblong to ovate, 1.5-2 cm. long: nuts 6-7 mm. long. 



— Spr. 



The Hop-HORXBEAJi grows in rich woods and hammocks in northern Florida and 

 in the northern part of the peninsula. The light-brown heart-wood is close-grained, 

 heavy, strong, tough, and durable. (Cont.) 



Family 2. BETULACEAE. Birch Family. 



Shrubs or trees, the wood close-grained. Leaves deciduous : blades 

 with 2-several series of teeth. Staminate aments drooping, Avith each 

 bract subtending- 2 or 3 flowers, the calyx present. Pistillate aments 

 seldom drooping, the bracts thickened and woocty, each one bearing 2 or 

 3 pistils, the calyx Avanting. Fruit a cone-like aggregate of the accrescent 

 bracts each of which subtends a nut. 



Stamens 2 : bracts of the mature pistillate aments membranous, 3-lobed, deciduous 

 with the nuts. 1. Betula. 



Stamens 4 (3-6) : bracts of the mature pistillate aments thickened 



and woody, persistent. 2. Alnds. 



1. BETTJLA [Tourn.] L. Shrubs or trees, the bark often aromatic. 



Staminate flowers with 2 stamens, the anther-sacs separated. Bracts of the 



pistillate aments 3-lobed, thin and appressed or ascending at maturity. — Spr. 



— Birch. 



Fruiting aments peduncled : bark not aromatic : leaf-blades dentate-serrate : nut- 

 body ovate to orbicular-ovate. 1. B. nigra. 



Fruiting aments terminating short branches and sessile : bark aro- 

 matic : leaf-blades sharply serrate : nut-body cuneate. 2. B. lenta. 



1. B. nigra L. Tree becoming 30 m. tall, the younger bark silvery or yellow: 

 leaf-blades rhombic-ovate, 3-6 cm. long, broadly cuneate at the base, more 

 or less tomentose beneath except in age: staminate aments with suborbicular 

 bracts: mature pistillate aments 3-4 cm. long, less than 1 cm. thick, the bracts 

 6-7 mm. long, tomentulose: wings of the fruit reniform-ciliate. 



The Red-birch grows in river swamps in northern Florida. The light-brown 

 heart-wood is close-grained and light, but both hard and strong. Also known as 

 River-birch. (Cont.) 



2. B. lenta L. Tree becoming 25 m. tall, the bark brown: leaf -blades ovate, 

 oblong-ovate, or oblong-lanceolate, 4-12 cm. long, rounded or cordate at the 

 base, silky on the nerves beneath: staminate aments with ovate bracts: 

 mature pistillate aments 1.5-3 cm. long, over 1 cm. thick, the bracts 5-6 mm. 



