scibpos C £ PERACE JE 680 



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 bristles 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 in vomeral bract. Perianth none. 



S. riparius Spreng. Stems tufted, from fibrous roots, very slender, 

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

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

 ing: spikelets ovate to ovate-oblong, U-3 lines long: scales pale 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 places near the coast 

 Oregon to California and South America. 



§ 2 Euscirpus Benth. Bristles present, retrorsely barbed or 

 ciliate, not elongated. 



* Inflorescence terminal, without involucre, 



S. nanus Spreng. Pug. i, 4. Annual: stems filiform, flattened, 

 grooved, tufted, ereot or ascending, 1-2 inches high, bearing bladeless scari- 

 ous sheaths near the base: spikelet solitary, ovoid-oblong, 3-8 -flowered, 1-1 1 

 lines long: scales ovate or lanceolate, pale green, the lower 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. pauciflorus Lightf. Fl. Scot. 1078. Perennial by filiform rootstocks : 

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

 spikelets solitary, oblong, 4-10-flowered, 2-3 lines long; scales brown with 

 lighter margins and midrib, lanceolate, acuminate: bristles 2-6, hispid, as 

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

 gray, rather abruptly beaked, its surface 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. 



S. subterminalis Torr. Fl, U. S. i, 47. Stems slender, terete, nodu- 

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

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

 3-5 lines long: involucral bract 6-12 lines long: scales ovate-lanceolate, acute, 

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

 the achene or shorter: stamens 3; style 3-cleft to about the middle: achenes 

 obovoid, 2-angled, dark brown, 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. 



8. Nevadensis Watson Bot. King, 360. Stems clustered, from run- 



