CYPERACEAE (SEDGE FAMILY) 189 



O. Bristles shorter than or about equaling the achene p. 

 p. Lower leaves and sheaths nodulose-reticulate ; bristles 

 nearly or quite equaling the achene. 

 Scales of the spikelet dark brown, orbicular-ovate, ab- 

 ruptly mucronate, 1.5-2 mm. long, one-third longer 

 than the achenes. 

 Some of the rays of the inflorescence elongate and defi- 

 nite 25. iS'. atrovirens. 



All the rays abbreviated and hidden in the dense inflo- 

 rescence (25) 5. atrovirens, v. pycnocephalus. 



Scales of the spikelet light brown, elliptic-ovate, narrowed 

 to a long setulose awn, about twice as long as the 



achenes 2&. S. j}alliduH. 



p. Lower leaves and sheaths smooth and hardly nodulose ; 



bristles shorter than the achene or often wanting . . 27. S. georgianus. 

 o. Bristles twice as long as the achene. 



Spikelets ovoid. 2.5-:3.5 mm. long 28. S. polyphyllus. 



Spikelets cyHndric. 5-S ram. long . (28) S. polyphyllus, v. macroatachys, 



I. Bristles smooth or with- few scattered or ascending hairs (not 

 regularly retrorse-barbedX bent or curled ; non-stoloniferous 

 plants in tufts or stools q. 

 q. Bristles at maturity scarcely exceeding the scales. 



Bristles firm, appressed, shorter than or about equaling the 



achene 29. 5. divaricaitts. 



Bristles weak, loosely ascending, about twice as long as the 

 achene. 

 Scales ^vith the strong green midrib prolonged into a sharp 



point 30. iS'. lineaiu^. 



Scales blunt, the midrib inconspicuous 31. <S. Peckii. 



q. Bristles at maturity much exceeding the scales r. 

 r. Spikelets all in glomerules of 3 to 15. 

 Involucels reddish-brown. 



Spikelets ovoid. 8-G mm. long 32. >?. cyperinus. 



Spikelets cylindric, 7-10 mm. long . . (32) S. cyperinus, v. Andrewsii. 

 Involucels dull brown or drab, with blackish bases. 

 Eays elongate, the glomerules mostly distinct . (32) S. cyperinus, v. pelius. 

 Kays abbreviated, the glomerules crowded in dense irreg- 

 ular masses (32) iS. cyperinus, v. condensatus. 



r. Lateral spikelets of each group mosth' pediceled (pedicels 

 short and obscure only in a variety with congested pan- 

 icles) s. 

 s, Involucels brown or reddish. 



Involucels bright red-brown or terra-cotta . . . '33. S. I/riophorum. 

 Involucels dull brown, not reddish. 

 Spikelets 3-6 mm. long, pale brown to straw-color . 34. S. pedicellaius. 

 Spikelets 7-10 mm. long, drab . . . (34) S. pedicellatiis, v. pullus. 



8. Involucels black. 



Rays mostly elongate, the raylets usually definite . . 35. S. atrocinctus. 

 Eays and raylets abbreviated, the spikelets crowded in 



" irregular masses (35) S. atrocinctus, v. brachypodtis. 



1. S. nanus Spreng. Culms densely tufted, bristle-like, flattened and grooved 

 (1-7 cm. high); spikelet ovoid, 8-8-flowered ; scales ovate, the 

 upper rather acute ; bristles mostly longer than the ovoid achene, 

 sometimes wanting. {Eleocharis pygmaca Torr. ) — Brackish 

 mar.^hes of the Atlantic coast : locally inland in N. Y., Mich., and 

 Minn. July-Sept. (Eu.. n. Afr., Mex.. Cuba.) Fig. 275. 2'^- ^- "^""^'• 



2. S. pauciflorus Lightf. Culms striate-angled, very slender 

 (0.5-4 dm. high), scarcely tufted, on slender running root- 

 stocks, with a short truncate sheath at base ; scales chestnut- 

 brown, pointless, all flower-bearing, the two lower larger ; 

 bristles 3-6, about as long as the achene. (Eleocharis Link.) 

 276 S pauciflorus — '^et calcareous soil. Que. to B. C, s. to n. N. E., N. Y., 

 Pa., 111., etc. June-Sept. (Eurasia.) Fig. 276. 



3. S. Clint6nii Gray. Culms acutely triangnJar. almost bristle-like ; sheaths 

 at the base bearing a very slender almost bristle-shaped leaf shorter (usually 

 very much shorter) than the culm ; outer scale mostly shorter 

 than the pale-chestnut ovoid spikelet; achene l.;'-2 mm. long, 

 compressed, broadlv obovoid, equaled or exceeded by the bristles. 

 — Dry bank.s, X. B. and Me. to w. N. Y. and Mich.; '' N. C." .,„ ^^ (^li^tonii. 

 May, June. Fkt. 277. 



4. S. planifblius Muhl. Culms triangular, leafy ai base ; leaves li^iear, flat, 



