394 OAK FAMILY. 



1. BETULA, BIECH. (The ancient Latin name.) Trees with slender 

 spray (or a few low shrubs), more or less spicy-aromatic twigs, sessile 

 scaly buds, flowers in early spring along with the leaves ; the sterile 

 catkins golden yellow ; the fertile ones mostly terminating very short 

 2-leaved branches of the season. 



* Trunk with brown or yellow-gray bark, the inner bark, twigs and thin 

 straight-veined leaves spicy -aromatic ; petioles short; thick fruiting 

 catkins with their thin scales rather persistent ; fruit with narrow wing. 



B. 16nta, Linn. SWEET, BLACK, or CHERRY BIRCH. A rather large tree, 

 60-75, with fine-grained valuable wood, dark brown close bark on the 

 trunk (not peeling in thin layers) and bronze-reddish twigs, very aromatic ; 

 leaves oblong-ovate and somewhat heart-shaped, sharply doubly serrate all 

 round, soon glossy above and almost smooth ; fruiting catkins oblong- 

 cylindrical, the scales with divergent lobes. Rich woods, N. Eng., W. and S. 



B. lutea, Michx. f. YELLOW or GRAY BIRCH. Less aromatic ; bark 

 of trunk yellowish-gray and somewhat silvery, separating in thin layers ; 

 leaves duller, more downy, and rarely at all heart-shaped ; fruiting cat- 

 kins short-oblong, with thinner and narrower barely spreading- lobed 

 scales. Same general range. 



* Trunk with chalky-white bark peeling horizontally in thin sheets ; 

 leaves and narrow cylindrical smooth catkins slender-stalked; bracts 

 fatting with the broad-winged fruit. 



B. dlba, Linn. EUROPEAN WHITE BIRCH, but much cultivated, partic- 

 ularly the weeping and cut-leaved forms ; tree 50-60, with open top, and 

 small (in the normal form) leaves which are triangular-ovate with a truncate 

 or rounded (or even somewhat cordate) base, and not strongly acuminate. 



B. populif61ia. Ait. AMERICAN WHITE BIRCH, GRAY BIRCH. Small 

 slender tree, 15-30, with mostly larger dangling leaves than the last, 

 very lustrous above, strongly triangular-ovate or diamond-ovate, the base 

 slanting, and the apex very long-acuminate. Poor soils, N. Eng. to Del., 

 and L. Ontario. 



B. papyrifera, Marsh. PAPER or CANOE BIRCH. Large tree, from upper 

 part of Penn. N., mostly far N. and N. W.; with ovate and even heart- 

 shaped leaves (dull and often pubescent beneath, and dark green above), 

 and more papery bark than in White Birch, separating in ample sheets. 



* * * Trunk with greenish-brown bark, hardly peeling in layers, reddish 

 twigs little aromatic, and oblong downy short-stalked catkins ; wings of 

 fruit broad. 



. B. nigra, Linn. RIVER or RED BIRCH. Middle-sized tree of low river 

 banks, commonest S. (but growing from Mass, to Minn, and S.); leaves 

 rhombic-ovate, whitish and mostly downy beneath. 



* * * Shrubs with brown tight bark, small thickish crenate leaves, and 

 oblong or cylindrical glabrous mostly erect short-peduncled catkins. 

 B. pumila, Linn. Low or DWARF BIRCH. Erect or ascending, 2-8 ; 

 leaves obovate or orbicular, soft-downy beneath. Bogs, Conn., S. and W. 



2. ALNUS, ALDER. (Ancient Latin name. ) Small trees or shrubs, 

 with narrow leaf-buds of very few scales and often stalked, and catkins 

 mostly clustered or racemed on leafless branchlets or peduncles. 



Flowers with the leaves in spring, the sterile from catkins which were 

 naked over winter, while the fertile catkin was inclosed in a scaly bud. 

 A. viiidis, DC. GREEN or MOUNTAIN ALDER. On mountains and far 

 N.; 3-8 high ; leaves round-oval or ovate, glutinous ; fruit with a broad 

 thin wing. 



