Class III. Order III. 19 



the tips of the glumes spreading so as to give a serrate appear- 

 ance to the edge as remarked by Dr. Torrey Edges of water. 

 September. 



CYPERUS STRIGOSUS. JL. Narrow spiked Cyperus. 



Spikelets linear, spreading or rofiexed, ten or 

 twelve flowered ; root globose. 



A foot or more in height. Umbel mostly simple, the spike- 

 lets numerous, narrow, and inserted into their common stalk 

 nearly at right angles. Low grounds. August, September. 

 Perennial. 



CYPERUS MARISCOIDES. Ell. Tuberous Cyperus. 



Umbel simple with one or two rays ; spikelets 

 seven or eight flowered, collected into dense spheri- 

 cal heads ; root globose. 



Eight or ten inches high. Root a solid bulb. Spikelets crowd- 

 ed into hard, dense heads. Plentiful on the barren sand in the 

 lower part of Watertown. July, August. Perennial. 



Subgenus DULICHIUM. Spikelets racemed^ slyle bijid. 

 CYPERUS SPATHACEUS. Lt. Sheathed Cyperus. 



Culm round, leafy ; leaves alternate, witli entire 

 sheaths ; racemes axillary and terminal. 



Syn. SCIKPUS SPATHACEUS. Mich. 



DULICHIUM SPATHACEUM. Reichard. 



A tall leafy grass. Stem smooth, hardly three sided, covered 

 with numerous, short, flat, smooth, spreading leaves, proceeding 

 from sheaths which are perfectly entire or tubular, the part op- 

 posite the leaf ending in a rounded point. The lower leaves, 

 not the sheaths, are deciduous. Racemes mostly axillary. Pe- 

 duncle compressed, bearing from five to eight alternate, sessile, 

 narrow spikelets of about six flowers. Glumes two ranked. 

 Seeds surrounded with hairs. Borders of ponds and rivers. 

 August. Perennial. 



19. SCIRPUS. 



Subgenus ELEOCHAHIS. Seed surrounded with bristles 

 style articulated to the seed, conical and persistent . 



