GRAM1NEAE. 39 



i 13. CENCHRUS L. Hedgehog or Bur-grass. 



Involucres less than 5 mm. broad. '1. Cj tribuloides. 



Involucres more than 5 mm. broad. 2. C. macrocephalus. 



1. Cenchrus tribuloides L. M. p. 90. Sandy shores, and waste places. 



Summer. 

 Philadelphia— (P.). Bucks— Near Delaware River (Fr.). Delaware— 

 Swarthmore (Pr.), Concord (W. tr.), Tinicum (B. Sm.). Chester— (P.). 

 Lancaster— {P.) Lehigh— Allentbwn (Kr.). Northampton — (P.). Dau- 

 phin — (P.). 

 New Jersey— Common. 

 New Castle— 'New Castle and Collins, common. 



2. Cenchkus macrocephalus (Doell.) Scribn. M. p. 1042. Along the sea- 



shore. Summer. 

 Cape May— Stone Harbor (St.). 



14. ZIZANIA L. 

 1. Zizania aquatica L. Wild Rice, Reed, Indian Rice. M. p. .91, Swamps. 

 Summer. 



15. HOMALOQENCHEXJS Mieg. 



Spikelets 2.5-3 mm. long; panicle branches usually rigid. 1. S. Virginicus. 

 Spikelets 4-5 mm. long; panicle branches generally lax. 2. S. orygoides. 



1. Homalocencheus Virginicus (Willd.) Britton. White Grass. M. p. 91. 



"Wet woods or swamps. Summer. 



Philadelphia— Byberry, Mart. (B. C), Wissahickon (VP.). Bucks — 

 Sellersville (Pr.). Delaware— Media (B. Sm.), Concord (W. Tr.). Ches- 

 ter— (P.). Lancaster— {P.). Northampton— Easton, Porter (B. C). 



Camden— Merchantville (Sts.). Gloucester — Mickleton (He.), Swedes- 

 boro (Li.). Salem— Woodstown (Te.). Bunterdon — Clinton (Te.). 



New Castle— Common. 



2. Homalocenoheus OBYZOiDEs (L.) Poll. Rice Cut-grass. M. p. 91. "Very 



wet places. Summer. 



16. PHALAEIS L. 



Outer scales not winged. 1. P. arundinacea. 



Outer scales broadly winged. 2. P. Canariensis. 



1. Phalakis arundinacea L. Reed Canary-grass. M. p. 92. Wet grounds. 



Summer. 



2. Phalaris Canariensis L. Canary-grass. M. p. 92. Waste places. 



Summer. 



17. ANTHOXANTHUM L. 



1, Anthoxanthum odoratum L. Sweet Vernal Grass. M. p. 92. Meadows 

 and pastures. Early summer. 



18. SAVASTANA L. 



1. Savastana odorata (L.) Scribn. Boly-grass. M. p. 93. Moist mead- 

 ows near the coast. Summer. 



