162 CYPERACEAE 



Perianth wanting. 



Stigmas 3 : style deciduous. 



Inflorescence paniculate : 17. Cladium. 



Inflorescence capitate : 18. Remirea. 



Stigmas 2 : style persistent. 19. Rynchospoea. 



Flowers monoecious or dioecious. 



Achenes not enclosed in a utricle (perigynium): 20. Scleria. 



Achenes enclosed in a utricle (perigynium): 21. Carex. 



1. LIPOCARPHA R. Br. 



Low annual slender herbs, with tufted scapes, and terete many-flowered spikelets in a 

 terminal head, subtended by an involucre of 1-several bracts. Scales firm, spirally imbri- 

 cated, all fertile or several of the lower ones empty, at length deciduous, each enclosing 2 

 bractlets which are convolute around the ovary. Flowers perfect. Perianth wanting. 

 Stamens 1-2. Style deciduous, its base not swollen. Stigmas 2-3. Achene plano-convex 

 or 3-angled. 



1. Lipocarpha maculata (Michx. ) Terr. Glabrous. Scape grooved, compressed, 

 smooth, longer than the narrowly linear somewhat channeled leaf-blades, 7-25 cm. tall : 

 bracts of the involucre 2-4 : sj^ikelets ovoid-oblong, obtuse, 5-6 mm. long, 2 mm. thick, in 

 a terminal capitate cluster : scales rhombic or lanceolate, acute, curved, the sides nearly 

 white, or flecked with reddish brown spots : exterior bractlet con volute 'around the achene, 

 nerved, hyaline : stamen 1 : achene oblong, yellowish, contracted at the base. 



In wet or moist soil, eastern Virginia to Florida. Also adventive farther north. Summer and fall. 



2. HEMICARPHA Nees & Arn. 



Low tufted mostly annual caulescent herbs, with erect or spreading, almost filiform 

 stems and leaves, and terete small terminal capitate or solitary spikelets subtended by an in- 

 volucre of 1-3 bracts. Scales spirally imbricated, deciduous, each subtending perfect 

 flowers and a single posterior bractlet. Perianth wanting. Stamens 1-3. Style deciduous, 

 not swollen at the base. Stigmas 2. Achene oblong, turgid or lenticular. 



1. Hemicarpha micrantha (Vahl) Britton. Annual, glabrous. Stems compressed, 

 grooved, 2-10 cm. long, mostly longer than the setaceous smooth leaf-blades : spikelets 

 ovoid, many-flowered, obtuse, about 2 mm. long: involucral bracts usually much exceed- 

 ing the spikelets : scales of the spikelets brown, obovate, each with a short blunt spreading 

 or recurved tip : stamen 1 : achene obovoid-oblong, obtuse, mucronulate, little compressed, 

 light brown. 



In moist, sandy soil, Rhode Island to Pennsylvania, Iowa and Nebraska, Florida, Texas and Mex- 

 ico. Summer and fall.— A variety ranging from Kansas to Texas, H. micrantha an'stiddta Coville, has 

 pale cuneate-obovate scales each tapering into a squarrose awn about as long as the body. 



3. DULICHIUM L. C. Rich. 



Tall perennial herbs, with terete hollow, conspicuously jointed stems, leafy to the top, 

 the lower leaves reduced to sheaths. Spikes axillary, peduncled, simple or compound. 

 Spikelets 2 ranked, flat, linear, falling away from the axis at maturity (?), many-flowered. 

 Scales 2-ranked, carinate, conduplicate, decurrent on the joint below. Flowers perfect. 

 Perianth of 6-9 retrorsely barbed bristles. Stamens 3. Style persistent as a beak on the 

 summit of the achenes. Stigmas 2. Achenes linear-oblong. 



1. Dulichium arundinaceum (L. ) Britton. Stems stout, 3-10 dm. tall, erect: 

 leaves numerous : blades flat, 2-8 cm. long, 4-8 mm. wide, spreading or ascending, the 

 lower sheaths bladeless, brown toward their summits : peduncles 4-25 mm. long : spike- 

 lets narrowly linear, spreading, 1-2.5 cm. long, about 2 mm. wide, 6-12-flowered ; scale 

 lanceolate, acuminate, strongly several-nerved, appressed, brownish : bristles rigid, longer 

 than the achene : style long-exserted, persistent. [Z). spathareimi (L. ) Pers.] 



In wet or muddy places. Nova [Scotia to Ontario, Minnesota and Nebraska, Florida and Texas- 

 Summer and fall. 



4. CYPERUS L. 



Annual or perennial scapose herbs. Leaves basal : blades narrow. Scapes, in our 

 species simple, triangular, and with one or more bracts at the summit forming an invo- 

 lucre to the simple or compound, umbellate or capitate inflorescence. Rays of the umbel 

 sheathed at the base, usually very unequal, one or more of the heads or spikes commonly 

 sessile. Spikelets flat or nearly terete, the scales falling away from the rachis as they ma- 



