In mud about ponds and along ditches, and in and on edge of lakes, infrequent 

 in s.e. Tex., rare in e. Tex., and Okla. (LeFlore, Atoka and Pushmataha cos.), 

 summer; s.e. U.S. n. to N.E., N.Y. and Mo., w. to Kan., Okla. and Tex. 



2. Rhynchospora corniculata (Lam.) Gray. Horned-rush. Fig. 243. 

 Perennial, either tufted or usually with thick scaly rhizomes (these often broken 



off in specimens); culms 6-1 1 dm. long, erect, 3-9 mm. thick basally, triquetrous, 

 very leafy; basal sheaths becoming only slightly fibrous; inflorescence at maturity 

 loose-obovoid, ample, 7-15 cm. thick, the numerous branches ascending to spread- 

 ing; spikelets subulate, rich-brown, 15-23 mm. long, the distal third to half 

 consisting merely of the protruding distal part of the tubercle; bristles 2 to 4 

 (or 5), about a third to two thirds as long as the achenial body, stiff, brownish, 

 closely appressed; achenial body 4-5 mm. long, obovate, nearly flat on the 2 faces, 

 dark-brown; tubercle subulate, consisting of the indurated entire portion of the 

 style, 13-18 mm. long, pale buffy. 



Frequent in mud, on edge of lakes, along edge of swamps and in water of 

 ditches, in Okla. (Choctaw, McCurtain, Bowie, LeFlore and Sequoyah cos.), e. and 

 s.e. Tex., spring-summer, (fruiting into fall); s.e. U.S., n. to Del., Ky., Ind. and 

 Mo., w. to Okla. and Tex.; W.L 



Ours are nearly all of the var. interior Fern, in which the achenial body is 

 only about 1.5 times as broad as the base of the tubercle; a few are of the var. 

 corniculata in which the body is about twice as broad as the tubercle. 



3. Rhynchospora indianolensis Small. 



Tufted perennial; culms 5-9 dm. long, erect, 3-6 mm. thick basally, trique- 

 trous, leafy (especially in the basal part); terminal part of the inflorescence some- 

 what umbelliform, Cyperus-Vike, 4-9 cm. long, with several ascending rays each 

 bearing a dense roundish glomerule or capitulum of nearly sessile spikelets, usually 

 a reduced axillary part of the inflorescence present; spikelets 7-10 mm. long, 

 lanceolate, brown, acute, the tubercle only slightly if at all exserted; bristles 3 to 5, 

 about equaling the achenial body, stiff, appressed; achenial body 3.5-4 mm. long, 

 obovate, nearly flat on the 2 faces, dark brown; tubercle 3.5-4 mm. long, brown, 

 elongate-deltoid, acute or slightly acuminate. 



Locally frequent in mud, s.e. Tex., summer; endemic. 



4. Rhynchospora divergens M.A. Curtis. 



Tufted short-lived perennial (or annual?); culms 18-42 cm. long, 0.3-0.9 mm. 

 thick, erect; leaves numerous, 5-10 cm. long, setaceous-involute; terminal part 

 of the inflorescence umbel-like, 1-2 cm. long, and 1 cm. broad, occasionally 

 1 or 2 reduced axillary parts of the inflorescence present below; spikelets linear, 

 3- to 10-flowered, about 1 mm. thick, the fruits very quickly maturing in suc- 

 cession acropetally as the spikelet elongates, the scales and achenes falling as the 

 achenes mature, eventually as many as 5 to 8 fruits maturing from a single spikelet 

 but only 1 or 2 visible at any one time; scales brownish, about 1.5 mm. long; 

 bristles absent; achenial body 0.7 mm. long, obovate, white, the 2 faces convex 

 and under low magnification appearing smooth, under higher magnification faintly 

 cellular-reticulate; tubercle about 0.15 mm. long and 2 mm. broad, whitish, blunt. 



Rare in moist or wet sand, s.e. Tex. (Aransas and Montgomery cos.), summer; 

 S.C., Ga., Fla., Bah. L and Tex. 



5. Rhynchospora pusilla M. A. Curtis. 



Tufted short-lived Bulhostylis-Mke perennial; culms 15-30 cm. long, 0.2-0.7 

 mm. thick, erect; leaves numerous, 5-10 cm. long, setaceous-involute, terminal 

 part of the inflorescence reduced, somewhat umbel-like or corymbose, 6-20 mm. 

 long, 5-10 mm. broad, often reduced parts of the inflorescence also present from 



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