BETULACEAE (BIRCH FAMILY) 



2 a Nut usually about % in. broad; husk comparatively 



thick; common tree SHAG-BARK HICKORY. (H. ovata.) 



b Nut usually less than % in. broad ; husk comparatively 

 thin; tree not common 



SMALL-FRUITED HICKORY. (H. microcarpa.) 



3 a Leaflets 5, rarely 7; twigs not hairy. .PIGNUT. (H. glabra.) 

 b Leaflets 7-11 ; twigs usually hairy 4 



4 a Leaflets usually 7, broadly lanceolate to obovate; buds 



with thin scales; twigs comparatively coarse; husk 



thick MOCKERNUT. (H. alba.) 



b Leaflets 7-11, narrowly lanceolate; buds without thin 

 scales, yellowish; twigs comparatively slender; husk 



thin BITTERNUT. (H. minima.) 



3 PTEROCARYA CAUCASIAN WALNUT. (P. fraxini folia*) 



5 FAGALES. Beech Order, 

 i BETULACEAE. Birch Family. 



1 CARPINUS BLUE BEECH. (C. caroliniana.) 



2 6STRYA IRONWOOD. (O. virginiana.) 



3 C6RYLUS. 



1 a Bracts of nut elongated into a beak 1-2 in. long; leaves 



ovate BEAKED HAZELNUT. (C. rostrata.) 



b Bracts of nut not as in a; leaves roundish-heart-shaped 2 



2 a Nut about Vz in. long; native species 



HAZELNUT. (C. americana.) 

 b Nut % in. or more long; cultivated species 



FILBERT. (C. avellana.*) 



4 BfiTULA. 



1 a Leaves triangular 2 



b Leaves ovate 3 



2 a Bark not readily peeling off in thin sheets, close on 



trunk; native species GRAY BIRCH. (B. populifblia.) 



b Bark readily peeling off in thin sheets, loose on trunk ; 



cultivated species. .EUROPEAN WHITE BIRCH. (B. alba.*) 



3 a Shrub growing in bogs Low BIRCH. (B. pumila.) 



b Trees not growing in bogs 4 



4 a Bark creamy white, readily peeling in thin sheets, 



loose on trunk CANOE BIRCH. (B. papyrifera.) 



b Bark yellowish to gray or brown 5 



5 a Bark yellowish, peeling in thin strips or sheets, loose 



on trunk YELLOW BIRCH. (B. lutea.) 



b Bark not completely as in a 6 



6 a Bark greenish-brown to reddish, in loose layers, not 



sweet or aromatic RIVER BIRCH* (B. nlgra.J 



b Bark dark-brown or ashy-gray, close or loose and peel- 

 ing in plates, sweet and aromatic. SWEET BIRCH. (B. lenta.) 



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