CYPERACEAE. 179 



' the inflorescence; spikelets 3-10 in a dense terminal simple head, oblong cylindric, 

 1.5-2.5 cm. long, 58 mm. in diameter; scales ovate, pale brown, 2-toothed at the 

 apex, the midvein excurrent into an ascending or spreading awn; bristles 

 1-3, much shorter than the achene or none; style 2-cleit; achene lenticular, 

 obovate or oblong-ovate, mucronulate, yellow-brown, its surface strongly cellular- 

 leticulated. On wet prairies and plains, Man. and Minn, to Neb., Kans. and 

 Mex., west to Nev. May-Aug. (S. campestris Britton, not Willd. ) 



19. Scirpus robustus Pursh. Salt Marsh Bulrush. (I. F. f. 627.) 

 Perennial by rootstocks-, culm stout, stiff, 3-angled with flat sides, smooth, 0.5-1.4 

 in. tall. Leaves dark green, smooth, 5-10 mm. wide; involucral leaves 2-4, elon- 

 gated, similar; spikelets ovoid-oblong, stout, 1. 5-2. 5 cm. long, 8-10 mm. in 

 diameter, 6-20 together in a dense terminal cluster; scales ovate, brown, puberu- 

 lent. thin, the midvein excurrent into an, at length, reflexed awn 3-5 mm. long; 

 bristles 1-6, fragile, shorter than the achene, or none; style 3-cleft; achene com- 

 pressed, flat on the face, convex or with a low ridge on the back, obovate -orbicular, 

 dark brown, shining, 3 mm. long. In salt marshes, N. S. to Tex. July-Oct. 



20. Scirpus fluviatilis (Torr.) A. Gray. River Bulrush. (I. F. f. 628.) 

 Perennial by rootstocks; culm stout, smooth, triangular with nearly flat sides, 0.9-2 

 m. tall. Leaves 8-16 mm. wide, smooth, attenuate to a very long tip; those of the 

 involucre 3-5, erect or spreading, often 20 cm. 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 sessile, oblong-cylindric, acute, 1.6-2.5 cm - l° n g> about 7 mm. in 

 diameter; scales ovate, scarious, puberulent, the midvein excurrent into a curved 

 awn 3-4 mm. long; bristles 6, downwardly barbed, about as long as the achene; 

 style 3-cleft; achene sharply 3-angled, obovoid, rather dull, short-pointed, 4 mm. 

 long. In shallow water, Que. to Minn., N. J., Neb. and Kans. June-Sept. 



21. Scirpus Novae- Angliae Britton. New England Coast Sedge. 

 (I. F. f. 627a.) Perennial by rootstocks; culm stout, 1-2 m. tall, sharply 

 3-angled. Leaves long, 8-12 mm. wide, roughish on the margins when dry, the 

 lowest reduced to pointed sheaths, those of the involucre 2-5, the longer of them 

 much exceeding the inflorescence; spikelets narrowly cylindric, acute, 1. 8-5 cm. 

 long, less than 8 mm. thick, solitary or 2-5 together at the ends of the rays ; rays 

 2-10 cm. long; scales awned; bristles 2-4, shorter than the grayish-white dull 

 obovate achene, which is distinctly 3-angled; style 3-cleft. In fresh water and 

 brackish marshes, Conn, and S. N. Y. 



22. Scirpus sylvaticus L. Wood Bulrush. (I. F. f. 629.) Perennial by 

 long rootstocks; culm triangular, stout, smooth, 1-2 m. tall, often overtopped by 

 the upper leaves. Leaves 1-1.6 cm. wide, rough on the margins, those of the 

 involucre 5-8, the larger often 0.3 m. long or more; umbel terminal, very large, 

 sometimes 2 dm. broad, about 3 times compound, the spikelets ovoid or ovoid- 

 oblong, 3-5 mm. long, in capitate clusters at the ends of the ray lets; bractlets of 

 the involucels small, linear or lanceolate; scales ovate-oblong, obtuse, brown with a 

 green centre; bristles 6, downwardly barbed, slightly exceeding the achene; sta- 

 mens 3; style 3-cleft; achene oblong, 3-angled, obtuse, nearly white, mucronulate. 

 In swamps, N. H. to N. Car. Also in Europe. June-Aug. 



23. Scirpus atrovirens Muhl. Dark-green Bulrush. (I. F. f. 630.) 

 Perennial by rootstocks; culms triangular, rather slender, leafy, 0.5-1.2 m. high. 

 Leaves elongated, nodulose, dark green, 6-12 mm. wide, one or two of them 

 usually exceeding the inflorescence; spikelets ovoid-oblong, acute, densely capi- 

 tate at the ends of the rays or raylets; involucels short; scales greenish -brown, 

 oblong, acute, the midvein excurrent; bristles usually 6, downwardly barbed above, 

 naked below, about as long as the achene; stamens 3; style 3-cleft; achene obiong- 

 obovoid, 3-angled, pale brown, dull. In swamps, N. S. to Manitoba, Ga. and La- 

 June-Aug. 



Scirpus atrovirens plllidus Britton. Whole plant pale green ; scales awned; spikelets 

 oblong-cylindric, very numerous in the capitate clusters. Minn, to the N.W.Terr, and Colo. 



24. Scirpus microcarpus Presl. Small-fruited Bulrush. (I. F. f. 631.) 

 Perennial; culms 0.9-1.6 m. tall, often stout, overtopped by the leaves. Longer 

 leaves of the involucre usually exceeding the inflorescence; spikelets ovoid-oblong, 

 acute, 3-4 mm. long, in capitate clusters at the ends of the usually spreading ray- 



