1. Sclrpus cubensis Poepp. & Kunth. 



Rhizomatous perennial; rhizome 1-5 mm. thick; aerial culms solitary at the 

 nodes of the rhizome, to 1 m. tall, sharply trigonous, smooth; leaves all basal 

 with blades to 15 mm. broad; inflorescence involucrate, umbel-like; bracts 2 to 

 5, leaflike, spreading, unequal, often much-elongate, far-surpassing the umbel; 

 branches of umbel very unequal (1 head usually quite sessile), usually 1-3 cm. 

 long; each branch terminated by a dense spherical or somewhat prolate head 1-2 

 cm. thick; each head of many spikelets; scales about 3 mm. long, reddish, spread- 

 ing, tapered to the acute reflexed tip; bristles absent; style bifid; achene about 3 

 mm. long, lenticular, apiculate. 



Very rare, known only from Eagle Nest Lake, Brazoria Co., Tex. where collected 

 once in 1958, summer-fall; warmer parts of Am., n. to Gulf States; also Afr. 



2. Scirpus fluviatilis (Torr.) Gray. River bulrush. Fig. 175. 



Perennial sedge with horizontal rhizomes forming tubers; culms stout, sharply 

 triangular, erect, 1-1.5 m. tall; leaves 8-16 mm. wide; involucral leaves 3 to 5, 

 unequal in length, to 20 cm. long; inflorescence umbellate, rays 5 to 12, elongate, 

 recurved-spreading, up to 12 cm. long; spikelets acute, 1.6-4 cm. long; bristles 6, 

 retrorsely barbed, stiff, unequal in length, nearly as long as the achene; anthers 

 2.5-4.5 mm. long; style trifid; achene usually sharply triangular, angled on back, 

 dull gray-brown, 4-5 mm. long. 



In shallow water and wet mud of sloughs, swamps, lakes, and along rivers and 

 streams, in N. M. (Fernald); Que. to Sask. and Wash., s. to Va., Ind., 111., Mo., 

 Kan.. N.M. and Calif. 



3. Scirpus maritimus L. Salt-marsh bulrush. 



Rhizomatous perennial; rhizome several mm. thick, extensive; culms tufted 

 along the rhizome, often with tuberlike enlargements basally, 5-20 mm. thick 

 above the tuber, 30-100 cm. long, erect, triquetrous; leaves several, well- 

 developed; bracts several, flat, leaflike, ascending or usually spreading; inflores- 

 cence of 3 to 15 ovoid to ovoid-cylindric erect or ascending spikelets, either all 

 sessile or some variously sessile and others peduncled, quite variable; scales 6-10 

 mm. long, almost as broad, apically mostly refuse and the midnerve prolonged 

 into a point 1-3 mm. long; achenes obovate-apiculate, 3^ mm. long, about 2 mm. 

 broad, in transection biconvex or one of the sides more convex or bifaceted than 

 the other, ripening to a dark-brown. The species is nearly world-wide. 



We have 2 varieties: 



Var. macrostachyus Michx. Scales firm, maturing to a dark-brown; styles usually 

 3-branched. S. robustus Pursh. 



Coastal marshes, s.e. Tex. and Rio Grande Plains, spring-summer-fall. 



Var. paludosus (A. Nels.) Koyama. Fig. 176. Scales thin, translucent, whitish 

 to pallid-buff; styles uniformly 2-branched. S. paludosus A. Nels. 



Marshes, salt flats and in mud about ponds and lakes, and along streams, in 

 Okla. (Ottawa. San luan, Colfax, Washita, Blaine and Alfalfa cos.), n.-cen. and 

 Trans-Pecos Tex., the Plains Country, Edwards Plateau and Rio Grande Plains, 

 N. M. (Dona Ana, San Juan. Chaves, Colfax, Quay and Eddy cos.) and Ariz. 

 (Apache, Navajo, Coconino and Mohave to Pinal and Maricopa cos.) 



4. Scirpus cyperinus (L.) Kunth var. rubricosus (Fern.) Gilly. Fig. 177. 



Perennial probably from short thick rhizomes; culms 8-20 dm. long. 6-13 

 mm. thick basally. 3-4 mm. thick apically where obscurely trigonous; leaves 

 numerous; bracts several, leaflike, basally brownish or reddish-brown, ascending, 

 the lowest one about as long as or slightly surpassing the inflorescence, the rest 

 much shorter; inflorescence a dense decompound panicle (some of the longer 

 primary branches 5-11 cm. long), somewhat droopy, of 200 to 500 spikelets. 



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