182 Cyperaceae Hemicarpha 



Flowers with bristles; achenes beaked; inflorescence axillary 



458. Dulichium, p. 183. 



Scales of the spikelets spirally imbricated. 



Base of style persistent on the achene as a tubercle. 



Spikelets 1; leaves reduced to sheaths; bristles usually present 



469. Eleocharis, p. 198. 



Spikelets several or numerous; leaves blade-bearing; bristles none 



471A. Bulbostylis, p. 206. 



Base of style not persistent as a tubercle. 

 Flowers without any inner scales. 



Base of style enlarged; bristles none 471. Fimbristylis, p. 205. 



Base of style not enlarged; bristles usually present. 

 Bristles 6 but each 4-6-cleft to near the base, making them appear num- 

 erous, silky, usually white, all much exserted; stamens 1-3 



466. Eriophorum, p. 190. 



Bristles 0-8, short, not silky and only rarely whitish and long-exserted, 



sometimes lacking; stamens 2 or 3 468. Scirpus, p. 192. 



Flowers with 1 or more inner scales. 



Bristles 3, barbed 467. Fuirena, p. 191. 



Bristles none 453. Hemicarpha, p. 182. 



Basal empty scales of the spikelets 3 or more. 



Styles 2-cleft; enlarged base of style persistent on the achene as a tubercle. 



Spikelets few-flowered; bristles usually present 492. Rhynchospora, p. 207. 



Spikelets many-flowered; bristles none 472. Psilocarya, p. 207. 



Styles 3-cleft; enlarged base of style not persistent on the achene; bristles none. 

 489. Cladium, p. 207. 



Flowers all imperfect. 



Pistillate flower subtended by a flat scale; achene naked, bony, and usually white. 



515. Scleria, p. 209. 



Pistillate flower wholly enclosed by a sac (perigynium), the style protruding through 

 an opening at the top 525. Carex, p. 212. 



453. HEMICARPHA Nees & Ain. 



Plants growing in dense clumps, the outer culms recurved-spreading; length of an 

 average culm (measured up to the inflorescence), 1-7 cm; height of leaves about 

 half the average length of the culms; longest involucral bracts (those appearing 

 as continuations of the culms) 2-4.5 cm long; average spikelets 2-4 mm long; scales 

 of spikelets generally with short, spreading or recurved tips; achenes terete, 

 slightly obovoid, usually about 0.6 mm long and 0.3 mm wide 1. H. micrantha. 



Plants growing in loose clumps, the culms erect or ascending; length of an average 

 culm (measured up to the inflorescence), 4-9 cm; height of leaves about a third 

 the average length of the culms; longest involucral bracts (those appearing as 

 continuations of the culms) 1-1.5 cm long; average spikelets 4-7 mm long; scales 

 of spikelets generally appressed; achenes terete or slightly lenticular-obovoid, 

 usually about 0.7 mm long and 0.35 mm wide 2. H. Drummondii. 



1. Hemicarpha micrantha (Vahl) Pax. Map 338. Infrequent to rare 

 in the area shown on the map. Found in wet, sandy places on the borders 

 of lakes and sloughs and in ditches. 



N. H., the Great Lakes area to Wash., southw. to Fla., Mex., and S. A. 



2. Hemicarpha Drummondii Nees. Map 339. Found only in wet sand 

 on the borders of sloughs or in sloughs when dried up, in wet, interdunal 

 flats in the dune area, and in a dredged ditch in Newton County. 



W. Ont., Ind., 111. to Ark., Kans., and Tex. 



