120 FLOE J OF PHILADELPHIA. 



Family 1, 3ETULACEAE Agardh. 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 amenta spike-like; nut 

 small, subtended by or enclosed in a large bractlet. 

 Fruiting bractlet flat, 3-clet't and incised. 1. Carpinus. 



Fruiting bractlet bladder-like, closed, membranous. 2. Ostrya. 

 Btaminate 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-elef t, 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. CAEPINUSL. 



1. Carpinus Caroliniana Walt. American Hornbeam, Blue Beech,, Water 

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



2. OSTEYA Seop. 



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

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



Philadelphia — Wissahickon (Lie.) (Me.). Bucks — Near Sellersville 

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

 ware— Chester Valley (Le.), Eadnor, J. Evans (B. Sm.), Kellyville (Te.), 

 Chester (W, Tr.). Chester — Valley Forge (Cr.), Willistown Twp. on& 

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

 Kiver, Salsburg (Kr.). Northampton— Easton, Porter (B. C). 



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



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



3. COEYLUS L. Filbert. 



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



lnvolucral 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— Eock Hill (Fr.). Mont- 

 gomery— Schwenksville* (TJ. C. S.). Chester— Valley Forge (Cr.) (W. Tr.), 

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

 (P.). Berks— Hamburg. Lehigh— Low Hill (Kr.). 



Hunterdon— Eosemont, Bloomsburg (C). 



New Castle — Eoeky 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. 



