GENUS 7. 



SEDGE FAMILY. 



333 



18. Scirpus paludosus A. Nelson. Prairie Bulrush. Fig. 818. 



Scirpus canipestris Britton, in Britton and Brown, 111. Fl. 



Ed. i, i: 267. 1896. Not Roth, 1795. 

 5". paludosus A. Nelson, Bull. Torr. Club 26: 5. 1899. 

 Scirpus interior Britton, Man. Ed. 2, 178. 1905. 



Perennial by slender rootstocks, culm slender, smooth, 

 sharply triangular, i-2 tall. Leaves usually pale 

 green, smooth, shorter than or overtopping the culm, 

 i "-2" wide, those of the involucre 2 or 3, the longer 

 much exceeding the inflorescence; spikelets 3-10 in a 

 dense terminal simple head, oblong-cylindric, mostly 

 acute, 8"-i2" long, 2\"-^' in diameter; scales ovate, 

 membranous, puberulent or glabrous, pale to brown, 

 2-toothed at the apex, the midvein excurrent into an 

 ascending or spreading awn about i" long; bristles 1-3, 

 much shorter than the achene or none; style 2-cleft; 

 achene lenticular, obovate or oblong-ovate, mucronulate, 

 yellow-brown. 



Salt marshes, Quebec to New Jersey, about salt springs 

 inland and on wet prairies and plains, Manitoba and Min- 

 nesota to Oregon, Nebraska, Kansas, Nevada and Mexico. 

 May-Aug. 



19. Scirpus robustus Pursh. Salt Marsh Bulrush. Fig. 819. 



Scirpus robustus Pursh, Fl. Am. Sept. 56. 1814. 

 Scirpus maritimus var. macrostachyus Michx. Fl. Bor. Am. 

 i : 32. 1803. Not S. macrostachyus Lam. 



Perennial by large rootstocks, culm stout, stiff, 

 sharply 3-angled with flat sides, smooth, 2-s tall. 

 Leaves equalling or overtopping the culm, dark green, 

 smooth, 2i"-5" wide, the midvein prominent ; involu- 

 cral leaves 2-4, elongated, erect, similar to those of the 

 culm, often i' long; spikelets ovoid-oblong, obtuse or 

 subacute, stout, 8"-i2" long, 4"-5" in diameter, 6-20 

 together in a dense often compound terminal cluster; 

 scales ovate, brown, puberulent, thin, lacerate or 

 2-toothed at the apex, the midvein excurrent into an, 

 at length, reflexed awn, \\"-2,\" long; bristles 1-6, 

 fragile, snorter than the achene or none; stamens 3; 

 style 3-cleft; achene compressed, very flat on the face, 

 convex or with low ridge on the back, obovate-orbic- 

 ular, dark brown, shining, li" long. 



In salt marshes, Nova Scotia to Texas. 

 Sea Club-rush. July-Oct. 



Spurt -grass. 



20. Scirpus fluviatilis (Torr.) A. Gray. River Bulrush. Fig. 820. 



Scirpus maritimus var. fluviatilis Torr. Ann. Lye. N. Y. 3 : 



324. 1836. 

 Scirpus fluviatilis ^Gray, Man. 527. 1848. 



Perennial by large rootstocks, culm stout, smooth, 

 sharply triangular with nearly flat sides, 3-6 tall. 

 Leaves 4"-8" wide, smooth, equalling or overtopping 

 the culm, attenuate to a very long tip, the midvein 

 prominent ; those of the involucre 3-5, erect or spread- 

 ing, some of them 5'-io' long; spikelets in a terminal 

 umbel, solitary, or 2-3 together at the ends of its long 

 spreading or drooping rays, or the central spikelets ses- 

 sile, oblong-cylindric, acute, 8"-i2" long, about 3*" in 

 diameter; scales ovate, scarious, puberulent, the midvein 

 excurrent into a curved awn i|"-2" long; bristles 6; 

 rigid, downwardly barbed, about as long as the achene; 

 style 3-cleft; achene sharply 3-angled, obovoid, rather 

 dull, short-pointed, 2" long. 



In shallow water along lakes and streams, Quebec to Min- 

 nesota, New Jersey, Nebraska and Kansas. River Club- 

 rush. June-Sept. 



