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 rnin. long, one-third longer 

 than the achenes. 



Some of the rays of the inflorescence elongate and defi- 

 nite 25. S. atrovirena. 



All the rays abbreviated and hidden in the dense inflo- 

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



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

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



achenes 26. S. pallidus. 



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 rnm. long 28. S. polyphyllus. 



Spikelets cylindric, 5-8 mm. long . . (28) S. polyphyllus, v. macrostachys. 

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

 regularly retrorse-barbed), 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. S. divaricatus. 



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



achene. 

 Scales with the strong green midrib prolonged into a sharp 



point 30. 8. lineatus. 



Scales blunt, the midrib inconspicuous SI. 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, 3-6 mm. long 32. S. cyperinus. 



Spikelets cylindric, 7-10 mm. long . . (32) 8. cyperinus, v, Andrewsii. 

 Involucels dull brown or drab, with blackish bases. 



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

 Kays abbreviated, the glomerules crowded in dense irreg- 

 ular masses (32) S. cyperinus, v. condematus. 



r. Lateral spikelets of each group mostly 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. Eriophorum. 

 Involucels dull brown, not reddish. 



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

 Spikelets 7-10 mm. long, drab . . . (34) 8. pedicellatus, v. pullus. 

 s. Involucels black. 



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

 Kays and raylets abbreviated, the spikelets crowded in 



irregular masses (35) S. atrocinctus, v. brachypodus. 



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

 (1-7 cm. high); spikelet ovoid, 3-8-flowered ; scales ovate, the 

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



sometimes wanting. {Eleocharis pygmaea Torr.) Brackish TV 



marshes of the Atlantic coast ; locally inland in N. Y., Mich., and 

 Minn. July-Sept. (Eu., n. Afr., Mex., Cuba.) FIG. 275. 



2. S. pauciflbrus 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 nauciflorus ~ Wet calcareous soil, Que. to B. C., s. to n. N. E., N. Y., 

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



3. S. Clintbnii Gray. Culms acutely triangular, 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 1.5-2 mm. long, ^ ffl 

 compressed, broadly obovoid, equaled or exceeded by the bristles. [ ^ 



- Dry banks, N. B. and Me. to w. N. Y. and Mich.; " N. C." m g clintonii 

 May, June. FIG. 277. 



4. S. planifblius Muhl. Culms triangular, leafy at base ; leaves linear, flat, 



