8CIRPU8 C f PEEACBiB 689 



3 SCIRPUS L. Sp, 47. 



Tufted annual or perennial herbs with creeping rootstocks, 

 leafy stems, or the leaves reduced to sheaths in some species, and 

 perfect flowers in a terminal or apparently lateral involucrate 

 cluster or compound umbel-like panicle. Spikelets usually many- 

 flowered, with the scales closely imbricated around the rachis, the 

 lower one or two often empty. Perianth of 3-6 hristles or none. 

 Stamens 1-3. Style 2-3-cleft. scarcely or not at all thickened at 

 base, deciduous or only the base persistent. Achenes lenticular 

 or more or less 3-angled or obovoid. 



§ 1 IsoLEPis Benth. Stems low and slender. Spikelets soli- 

 tary, small, with a single erect involucral bract. ^*erianth none. 



S. riparins Spreng. Stems tafted, from fibrous roots, very slender, 

 often setaceous, 2-10 inches high, sheathed at base, the upper sheath usually 

 bearing a short slender leaf: involucral bract 1-10 lines long or nearly want- 

 ing; spikelets ovate to ovate-oblong, lJ-3 lines long: scalespale or often deep 

 brown, with a pale prominent midrib, concave, obtuse or pointed: stamens 

 usually 3: style 3-cleft: achene triangular-obovoid, with distinct angles, the 

 sides convex, dark brown when mature. In marshy plapes near the coast 

 Oregon to Calif oi-nia and South America. 



§ 2 EusciRPUs Benth. Bristles present, retrorsely barbed or 

 ciliate, not elongated. 



* Inflorescence terminal, without involucre. 



8. nanus i^preng. Pug i, 4. Annual: stems filiform, flattened, 

 grooved, tufted, erect or ascending, 1-3 inches high, beaming bladeless scari- 

 0U8 sheaths near the base: spikelet solitary, ovoid-oblong, S-S-flowei'ed, 1-li 

 lines long: scales ovate or lanceolate, pale green, the lowgr obtuse, the upper 

 acutish: bristles about 6. longer than the achene: stamens 3: style 3-cleft: 

 achene oblong 3-angled, pale pointed at each end, smooth. Muddy places,' 

 Oregon to Alaska and the Atlantic States. 



S. panciflorns Lightf, Fl. Scot. 1078. Perennial by filiform rootstocks : 

 stems very slender little tufted, 3-10 inches high, tapper sheaths truncate : 

 spikelets solitaiy, oblong, 4-10-flowered, 3-3 lines;i,bzp; scales brown with 

 lighter mar^ns and midrib, lanceolate, acuminate^fistles 3-6, hispid, as 

 long as the achene or longer: stamens 3: style S-cleft: achene obovoid-oblong, 

 gray, rather abruptly beaked, its suif ace 'finely reticulated. In wet soil 

 along the Colnmbia river, Oregon to Brit. Columbia, Ontario and New York. 



* * Inflorescence apparently lateral, with a single involucral leaf. 



■^ Stems terete or nearly so. 



8. gubterminalis Torr. Fl, U. 8. i, 47. Stems slender, terete, nodu- 

 lose, 1-3 feet high: leaves slender, channelled, 6 inches to 2 feet long, |-f 

 line wide, spikelet soiltary, terminal, oblong-cylindric, narrowed at each end, 

 3-5 lines long: involucral bract 6-12 lines,loug:sca;les ovate-lanceolate, acute^ 

 membranaceous, light brown with green midrib: bristles about 6, as long as 

 the achene or shorter: stamens 3; Atyle 3-oleft to about the middle: achenes 

 obovoid, 2-angled, dark bj;own, smooth, about a line long, obtuse, abruptly 

 beaked by the slender base of the style. In ponds and streams, eastern 

 Washington to Pennsylvania and New Brunswick. 



S. Neradensis Watson Bot. King, 360. Stems clustered, from run- 



