268 CYPERACEAE. 
1g. Scirpus robistus Pursh. Salt Marsh Bulrush. (Fig. 627.) 
Scirpus robustus Pursh, Fl. Am. Sept. 56. _ 1814. 
Scirpus maritimus var, macrostachyus Michx. F1. 
Bor. Am. 1: 32. 1803. Not S. macrostachyus Lam. 
Perennial by large rootstocks, culm stout, stiff, 
sharply 3-angled with flat sides, smooth, 2°-5° 
tall. Leaves equalling or overtopping the culm, 
dark green, smooth, 214//-5’’ wide, the midvein 
prominent; involucral leaves 2-4, elongated, erect, 
similar to those of the culm, often 1/ long; spike- 
lets ovoid-oblong, obtuse or subacute, stout, 8’/—12// 
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. 114//-2%”’ long; bristles 1-6, fragile, 
shorter 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- 
orbicular, dark brown, shining, 114’ long. 
In salt marshes, Nova Scotia to Texas. July—Oct. 
20. Scirpus fluviatilis (Torr.) A. Gray. River Bulrush. (Fig. 628.) 
Scirpus maritimus var. fluviatilis Torr. Ann. Lye. N. | 
Y. 3: 324. 1836. 
Scirpus fluviatilis A. 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 5/10’ 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, 8’’/-12/” long, about 
314’ in diameter; scales ovate, scarious, puberulent, 
the ‘midvein excurrent into a curved awn 114//-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 
Minnesota, New Jersey, Illinoisand Kansas. June-Sept. | 
21. Scirpus sylvaticus L. Wood Bulrush. (Fig. 629.) 
X 7] Scirpus sylvaticus Yl. Sp. Pl. 51. 1753. 
Perennial by long rootstocks, culm triangular, 
stout, smooth, 4°-6° tall, often overtopped by the 
upper leaves. Leaves flat, 5’’/-8’’ wide, rough on 
the margins, more or less rugulose, the midvein 
prominent, those of the involucre 5-5, the larger 
similar to those of the culm and often 1° long or 
more; umbel terminal, very large, sometimes 8’ 
broad, about 3 times compound, the spikelets ovoid 
or ovoid-oblong, mostly acute, 114’’-2'%4’" long, 
borne in capitate clusters of 2-8 at the ends of the 
raylets; bractlets of the involucels small, scarious, 
linear or lanceolate; scales ovate-oblong, obtuse, 
brown with a green centre; bristles 6, downwardly 
barbed, slightly exceeding the achene; stamens 3; 
style 3-cleft; achene oblong, 3-angled, obtuse, 
nearly white, mucronulate, not shining. 
In swamps, Massachusetts to North Carolina. Also 
in Europe. June-Aug. 
