500 CYPERACE.E. (SEDGE FAMILY.) 



obovate, mucronate, plano-convex. Our plant appears constantly to have a 2- 

 cleft style, and the scales often a little downy on the back, and is S. validus, Vahl. 

 & S. acutus, Muhl. Fresh-water ponds and lakes; common. July. Culm 

 as thick a* the finger at the base, tipped with an erect and pointed involucral 

 leaf, which is shorter or longer than the panicle. (Eu.) 



8. S. di'bilis, Pursh. Culms slender (6' -12' high), striate, tufted, from 

 fibrous roots, leafless, or 1-leaved at the base ; spikes ovate, few (I -8) in a sessile 

 duster, appearing deeply lateral by the prolongation of the 1-leaved involucre ; 

 scales round-ovate (greenish-yellow) ; style 2-3-cleft; bristles 4-6, longer than 

 the obovate plano-convex or lenticular shining minutely dotted achenium, or 

 rarely obsolete. Low banks of streams, Massachusetts to Michigan, Illi- 

 nois, and southward. Aug. 



# # # Spikes clustered and mostly umbelled, plainly terminal, many-flowered: involu- 

 cre leafy : culm leafy, triangular, and with closed joints below (style 3-cleft). 

 t- Sca'es of the large spikes awl-pointed, lacerate-3-clefl at the apex. 



9. S. maritimus, L. (SEA CLUB-RUSH.) Leaves flat, linear, as long 

 as the stout culm (l-3 high), those of the involucre 1-4, very unequal; 

 spikes few -several in a sessile cluster, and often also with 1-4 unequal rays 

 bearing 1-7 ovate or oblong-cylindrical (rusty brown) spikes ; achenium obovate- 

 orbicular, much compressed, flat on one side, convex or olttuse-anglcd on the other, mi- 

 nutely pointed, shining, longer than the 1 -6 unequal and deciduous (sometimes 

 obsolete) bristles. Var. MACROSTACHYOS, Michx. (S. robustus, Pursh.) is a 

 larger form, with very thick oblong or cylindrical heads, becoming !'-!' long, 

 and the longer leaf of the involucre often 1 long. Salt marshes ; common on 

 the coast, and near salt springs (Salina, New York), &c. Aug. Heads beset 

 with the spreading or recurved short awns which abruptly tip the scales. (Eu.) 



10. S. Iliiviistilis. (RIVER CLUB-RUSH.) Leaves flat, broadly linear 

 ($' or more wide), tapering gradually to a point, the upper and those of the very 

 long involucre very much exceeding the compound umbel ; rays 5-9, elongated, 

 recur ved-spreading, bearing 1-5 ovate or oblong-cylindrical acute heads ; acheni- 

 um obovate, sharply and exactly triangular, conspicuously pointed, opaque, scarcely- 

 equalling the 6 rigid bristles. (S. marit., var. ? fluviatilis, Torr., excl. syn. EU.) 

 Borders of lakes and large streams, W. New York to Wisconsin and Illinois. 

 July, Aug. Culm very stout, sharply triangular, 3 - 4 high. Leaves rough- 

 ish on the margin, like the last; those of the umbel 3-7, the largest l-2 

 long. Principal rays of the umbel 3'-4 ; long, sheathed at the base. Heads |' 

 to 1 4' long, paler and duller than in No. 9 ; the scales less lacerate and A le awns 

 less recurved ; the fruit larger and very different. 



- +- Scales of the small compound-umbelled and clustered heads mucronate-tipped. 



11. S. SylvAticUS, L. Culm leafy (2 -5 high); leaves broadly linear, 

 flat, rough on the edges ; umbel cymose-decompound, irregular ; the numerous 

 spikes clustered (3-10 together) in dense heads, ovoid, dark lead-colored or olive- 

 green turning brownish ; bristles 6, downwardly barbed their whole Irnglh, straight, 

 scarcely longer than the convex-triangular achenium. Low grounds, N. New 

 England and northward. Var. ATR^VIRENS (S. atroviivns, Mn/il.) is a form 

 with the spikes (10-30 together) conglomerate into denser larger heads. Wet 



