334 BETULACEAE (BIRCH FAMILY) 



of the branches of the preceding year ; the fertile single, terminating short leafy 

 shoots of the season. (The classical name.) 



1. 0. virginiana (Mill.) K. Koch. (American Hop H,, Leverwood.) 

 Leaves oblong-ovate, taper-pointed, very sharply double-serrate, downy beneath, 

 with 11-15 principal veins; buds acute; involucral sacs bristly-hairy at the 

 base. (0. virginica Willd.) — Rich woods, N. S. to Man., Minn., Neb., and 

 southw. 



3. CARpiNUS [Tourn.] L. Hornbeam. Ironwood 



Sterile flowers similar to those of Ostrya. Fertile flowers several, spiked in 

 a sort of loose terminal catkin, with small deciduous bracts, each subtending a 

 pair of flowers ; the single involucre-like bract open, enlarged in fruit and foli- 

 aceous, merely subtending the small ovate several-nerved nut. — Trees or tall 

 shrubs, with close gray bark, in this and in the slender buds and straight-veined 

 leaves resembling the Beech ; leaf-buds and inflorescence as in Ostrya. (The 

 early Latin name. ) 



1. C. caroliniana Walt. (American H. ; Blue or Water Beech.) Leaves 

 ovate-oblong, pointed, sharply double-serrate, soon nearly smooth ; bractlets 

 3-lobed, halberd-shaped, sparingly cut-toothed on one side, acute. — Along 

 streams, N. S. to w Out., and southw. 



4. BETULA [Tourn.] L. Birch 



Sterile flowers 3 (the bractlets 2) to each shield-shaped scale or bract of the cat- 

 kins, consisting each of a calyx of one scale bearing 4 short tilaments with 1 -celled 

 anthers (or strictly of two 2-parted filaments, each division bearing an anther- 

 cell). Fertile flowers 2 or 3 to each 3-lobed bract, without bractlets or calyx, 

 each a naked ovary, becoming a winged and scale-like nutlet (or small samara) 

 crowned with the two spreading stigmas. — Outer bark often separable in sheets, 

 that of the branchlets dotted. Buds sessile, scaly. Sterile catkins terminal and 

 lateral, sessile, formed in summer, remaining naked through winter, and expand- 

 ing in early spring, with or preceding the leaves ; fertile catkins ovoid to cylin- 

 drical, usually terminating very short 2-leaved early lateral branches of the season. 

 (The ancient Latin name. ) 



* Trees or sJunibs ; the leaves with the 8 or more pairs of nerves impressed 

 above ; fruiting catkins thick (1 cm. or more), short-cylindric to ovoid, their 

 scales rather persistent ; loing of fruit not broader than the seed-bearing body. 



+ Bark and twigs siceet-aromatic ; leaves membranaceous, ovate to oblong-ovate, 

 with rounded or cordate bases, regularly serrate, green both sides ; fertile 

 catkins sessile, erect. 



1. B. lentaL. (Cherry, Sweet, or Black B.) Bark of trunk dark bi'own, 

 close, in age becoming ashy-brown and furrowed, very sweet-aromatic ; leaves 

 ovate or ovate-oblong from a more or less heart-shaped base, acuminate, sharply 

 and finely double-serrate, when mature bright green above and glabrous except 

 on the veins beneath ; fruiting catkins short-cylindric (1.5-2.5 cm. long) ; the 

 scales firm and smooth, \^T^h short and divergent lobes. — Rich woods, Nfd. to 

 Ont., s. to Del., Ind. and centr. la. ; also along the mts. to Fla. and Tenn. 



2. B. lutea Michx. f. (Yellow or Gray B.) Bark of trunk yellowish- or 

 silvery-gray, detaching in very thin filmy layers, less aromatic ; leaves slightly or 

 not at all heart-shaped and often narrowed toward the base, duller green above 

 and usually more downy on the veins beneath ; fruiting catkins narrow-ovoid 

 to subglobose, the more foliaceous scales mostly longer, pubescent and with nar- 

 rower barely spreading ciliate lobes. — Rich moist woods, Nfd. to Man., s. to Del., 

 111., and Minn. ; also along the mts. to Tenn. and N. C. — Trees with character- 

 istics somewhat intermediate between this and B. lenta have been called B. 

 alleghaniensis Britton. 



t- t- Bark not aromatic; leaves firm, rhombic-ovate, cuneate to subtruncate at 

 base, irregularly dentate-serrate, whitish beneath; fertile catkins peduncled^ 

 soft-downy. 



