Sl-DGK FAMILY. 2$, 



9. SCIRPUS L. Sp. PI. 47. i 753 . 



Annual or perennial very small or very large sedges, with leafy culm, or the leavw re- 

 duced to basal sheaths. Spikelets terete or somewhat flattened, Military, capitate. ptctr or 

 umbellate, subtended by a i -several-leaved involucre or the involucre wanting in <> 

 species. Scales spirally imbricated all around, usually all fertile, the I-; lower aoottttmr* 

 empty. Flowers perfect. Perianth of 1-6, slender or rigid, abort or elongated, bat bed. 

 pubescent or smooth bristles, or none in some species. Stamen* 1-3. Style 9-j-clefk, Dot 

 swollen at the base, wholly deciduous from the achene, or its hue persistent aa a tubaUt* 

 tip. Achene triangular, lenticular or plano-convex. [Latin name of the Hulrusb. said to 

 be from sirs, the Celtic word for rushes.] 



About 200 species of very wide geographic distribution Beside* the following. 

 occur in the southern and western parts of North Ann 



Spikelet solitary, terminal, bractless or subtended by a single bract or ahort 

 No involucral bract. 



Culms i '-2' high; achene smooth; plant of saline soil. s' 



Culms ,V-io' high; achene reticulated; plant of fresh-water marhr. 

 Involucral bract present, erect. 



Bract shorter than or but little exceeding the spikelet; plants not aquatic. 



Culm terete; leaf of upper sheath subulate : bristles MIKK.UI 3. 5. tmnjtilottu, 



Culms triangular; leaf of upper sheath linear; bristk-s upwardly barbed. 

 Leaves shorter than the culm ; scales acute. 4. .V 



Leaves about as long as the culm; scales cuspidate. 



Bract at least twice as long as the spikelet; plant aquatic. 6. A", \ubit rmt*lit. 



Spikelets normally more than i, usually several or numerous, often appearing lateral, invntocral 



bract only i . 

 Spikelets few, 1-12, appearing lateral. 



Culms not sharply 3-angled; achene plano-convex; annuals. 

 Achene strongly transversely rugose. 

 Achene smooth or very slightly roughened. 



Bristles downwardly barbed, about equalling the achene. 8. S. 4tt 



Bristles minute or wanting. 9. S. Smilkti 



Culms sharply 3-angled; plants perennial by rootstocks. 



Achene plano-convex; bristles shorter than or equalling the achrnc. 



Spikelets acute, much overtopped by the slender involucral leaf, scales award. 



s. Amtrtt***! 

 Spikelets obtuse; involucral leaf short, stout; scales mucronulate. 



u. S Ol'i 

 Achene 3-angled, ridged on the back. 



Bristles longer than the achene; involucral leaf erect. 



Bristles as long as the achene; involucral leaf abruptly bent. i,v -V *<rvm*tiu. 

 Spikelets several or numerous, umbelled; tall sedges. 



Culm sharply triangular, equalled by the long leaves. i \ -V. t> nJriem*. 



Culm terete; leaves reduced to sheaths. 



Bristles downwardly barbed; achene gray, abruptly mucronatr. 

 Bristles short-plumose below; achene nearly white, narrowed above. 



16. S. (*/!/. '!. 



Spikelets several, spicate. 



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 



Capitate cluster often compound; achene orbicular-obovate, dark brown. 



19. SI robt' 



Achene sharply 3-angled; Spikelets umbellate. 

 Spikelets very numerous in compound umbels or umbelled heads, si 



eral; tall sedges. 



Bristles downwardly barbed; spikelets in umbelled heads. 

 Spikelets ovoid or oblong, 1 54" -2 54" long. 



Bristles equalling or slightly exceeding the achene; leaves j* -) 

 Style 3-cleft; achene 3-angled; bristles 6. 



Spikelets 3-8 in each head; bristles barbed tl 



Spikelets 8-20 in each head; bristles not barbed below; scales acmtr 



Style 2-cleft; achene plano-convex: bristles 4. 

 Bristles flexuous, twice as long as the achene ; leaves a -3 wid 



Spi kelets cylindric, 3' ' -5' ' long. 





, - . 



Bristles smooth or slightly pubescent: umbel mostly deeOMtOI 

 Bristles shorter than or scarcely exceeding the s< 



Bristles about as long as the achene; scale* MMCrt 

 Bristles much longer than the achene; scales mucronate. 

 Bristles much exserted beyond the scales when mature. 



