SEDGE FAMILY. 261 
9. SCIRPUS L. Sp. Pl. 47.1753. 
Annual or perennial very small or very large sedges, with leafy culms or the leaves re- 
duced to basal sheaths. Spikelets terete or somewhat flattened, solitary, capitate, spicate or 
umbellate, subtended by a 1-several-leaved involucre or the involucre wanting in some 
* species. Scales spirally imbricated all around, usually all fertile, the 1-3 lower sometimes 
empty. Flowers perfect. Perianth of 1-6, slender or rigid, short or elongated, barbed, 
pubescent or smooth bristles, or none in some species. Stamens 2-3. Style 2-3-cleft, not 
swollen at the base, wholly deciduous from the achene, or its base persistent as a subulate 
tip. Achene triangular, lenticular or plano-convex. [latin name of the Bulrush, said to 
be from sirs, the Celtic word for rushes. ] 
About 200 species of very wide geographic distribution. Besides the following, some 6 others 
occur in the southern and western parts of North America. 
Spikelet solitary, terminal, bractless or subtended by a single bract or short leaf. 
No inv: olucral bract. 
Culms 1/-2’ high; achene smooth; plant of saline soil. 1. S. manus. 
Culms 3'-10' high; achene reticulated; plant of fresh-water marshes. 2. S. pauciflorus. 
Involucral bract present, erect. 
Bract shorter than or but little exceeding the spikelet; plants not aquatic. 
Culm terete; leaf of upper sheath subulate; bristles smooth, 3. S. caespttosus. 
Culms triangular; leaf of upper sheath linear; bristles upwardly barbed. 
Leaves shorter than the culm; scales acute. 4. S. Clintont. 
Leaves about as long as the culm; scales cuspidate. 5. S. plantfolius. 
Bract at least twice as long as the spikelet; plant aquatic. 6. S. subterminalis. 
Spikelets normally more than 1, usually several or numerous, often appearing lateral; involucral 
bract only 1. 
Spikelets few, 1-12, appearing lateral. 
Culms not sharply 3-angled; achene plano-convex; annuals. 
Achene strongly transversely rugose. 7. S. Hallit. 
. Achene smooth or very slightly roughened. 
Bristles downwardly barbed, about equalling the achene. 8. S. debilis. 
Bristles minute or wanting. g. S. Smithiz. 
Culms sharply 3-angled; plants perennial by rootstocks, 
Achene plano-convex; bristles shorter than or equalling the achene. 
Spikelets acute, much overtopped by the slender involucral leaf; scales awned. 
10. S. Americanus. 
Spikelets obtuse; involucral leaf short, stout; scales mucronulate. 
11. SS. Olneyi. 
Achene 3-angled, ridged on the back. 
Bristles longer than the achene; involucral leaf erect. 12. S. Torreyz. 
Bristles as long as the achene; involucral leaf abruptly bent. 13. S. mucronatus. 
Spikelets several or numerous, umbelled; tall sedges. 
Culm sharply triangular, equalled by ‘the long leaves. 14. 'S. 
Culm terete; leaves reduced to sheaths. 
Bristles downwardly barbed; achene gray, abruptly mucronate. 15. S. lacustris. 
Bristles short-plumose below; achene nearly white, narrowed above. 
16. S. Californicus. 
Spikelets several, spicate. 17. S. rufus. 
Spikelets several, capitate or umbellate, large; involucral leaves 2 or more. 
Achene lenticular or plano-convex; spikelets capitate. 
Capitate cluster simple; achene obovate- oblong, pale brown. 18. S. campestris. 
Capitate cluster often compound; achene orbicular-obovate, dark brown. 
19. S. robustus. 
Achene sharply 3-angled; spikelets umbellate. 20. S. fluviatilis. 
Spikelets very numerous in compound umbels or umbelled heads, small; involucral leaves sev- 
eral; tall sedges. 
Bristles downw ardly barbed; spikelets i in umbelled heads. 
Spikelets ovoid or oblong, 1'4''-2%4"' long. 
Bristles equalling or slightly exceeding the achene; leaves 3/’-8'’ wide. 
Style 3-cleft; achene 3-angled; bristles 6. 
Spikelets 3-8 in each head; bristles barbed throughout; Beales obtuse. 
S. sylvaticus. 
Spikelets 8-20 in each head; bristles not barbed below; scales acute. 
22. S. atrovirens. 
. cvlindricus. 
nn 
Style 2-cleft; achene plano-convex; bristles 4. 23. S. microcarpus. 
Bristles flexuous, tw ice as long as the achene; leaves 2'’—3'' wide. 24. S. polyphyllus. 
Spikelets cylindric, 3'’-5/’ long. 25. S. Peckit, 
Bristles smooth or slightly Saedee nth umbel mostly decompound, 
Bristles shorter than or scarcely exceeding the scales. 
Bristles about as long as the achene; scales subacute. 26. S. divaricatus. 
_ Bristles much longer than the achene; scales mucronate. 27. S. lineatus. 
Bristles much exserted beyond the scales when mature. 28. S. cvperinus. 
