120 FLOh'A OF PHILADELPHIA. 



Family 1. BETULACEAE Asjardh. Birch Family. 



Btaminate 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, subtended 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. Corylus. 



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

 tillate flowers without a calyx. 

 (Stamens 2; filaments 2-cleft, each fork bearing an anther-sac; fruit- 

 ing 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. 



1. (Jakpinus Caroliniana Walt. American Hornbeam, Blue Beech, Water 

 Beech. M. p. 326. Along streams. Spring. 



2. OSTRYA Scop. 



1. Ostrya Virginiana (Mill.) Willd. Hop-hornbeam, Ironwood, Lever- 

 wood. M. p. 327. Dry woods. Spring. 



P/iiZadeZp7ua — Wissahickon (Le.) (Me.). J5«cfcs — Near Sellersville 

 (Fr.), Narrowsville (Ja.), Rock Hill (Mac), New Hope (Ws.). Dela- 

 ware— Chester Valley (Le.), Radnor, J. Evans (B. Sm.), Kellyville (Tc), 

 Chester (W. Tr.). Chester— \s\\ej Forge (Cr.), Willistown Twp. one 

 tree (Pr.). Lancaster— Paradise (St.). Lehigh — Jordan and Lehigh 

 River, Salsburg (Kr.). Northampton— ^a&toii, Porter (B. C). 



Hunterdon — Along the Delaware (C). Somerset — Roxiticus (C). 



New Castle— 'Near Fish Ponds, Naaman's Creek. 



3. CORYLUS L. Filbert. 



Involucre of 2 broad laciniate bractlets. 1. C. Americana. 



Involucral bractlets united, prolonged into a tubular bristly beak. 



2. C. rostrata. 



1. Corylus Americana Walt. Wild Hazel-nut. M. p. 327. Thickets. 



Early spring. 



2. Corylus rostrata Ait. Beaked Hazel. M. p. 327. Thickets. Spring. 



Philadelphia— 'Wissahickon (Me.). Bucks— Boek Hill (Fr.). Mont- 

 gomery— iich^\enksvi\l(i {JJ. C. S.). Chester— Valley Forge (Cr.) (W. Tr.), 

 Coatesville, H. E. Stone (B. C), Nottingham Twp. (Pr.). Lancaster— 

 (P.). Berts— Hamburg. Lehigh— Ijow Hill (Kr.). 



Hunterdon— Jiosemojit, Bloomsburg (C). 



New Castle— 'Rocky hillsides at High Bridge, N. side. 



4. BETULA L. 



Fruiting aments peduncled; bark chalky-white. 1. B. populifolia. 



Fruiting aments peduncled; bark greenish-brown or brown. 



2. B. nigra. 

 Fruiting aments sessile, at the ends of short branches; bark brown or 

 yellowish. 



