ELEOCHARIS. CLX. CYPERACE.E. 569 



TRIBE 3. SCIRPEJE. Flowers $ Glumes of the spikelet imbricated all 



around. Perigynium none, or setaceous. 



6. ELEOCHARIS. R. Br. 



Gr. cXoj, a marsh, %aipo>, to rejoice ; plants delighting in marshy grounds. 



Spikes terete ; bristles of the perigynium mostly 6 (3 12), rigid, 

 persistent ; styles 2 3-cleft, articulated to the ovary ; achenium 

 crowned with a tubercle which is the persistent, bulbous base of the 

 style. Stem simple, leafless. Spike solitary, terminal. 



Spikes cylindrical, length more, than three times the diameter. 



1. E. EQUISETOIDES. Torr. (Scirpus. Elliott.') Horse-tail Rush. 



St. about 2f high, papillose, terete, 2 3" diam., with about 20 joints, pro- 

 duced by internal, transverse partitions ; sheath radical, obtuse, membranous ; 

 spike oblong-cylindrical, about 1' in length, acute and slightly contracted at 

 oase ; glumes roundish-ovate, cartilaginous, obtuse ; bristles 6, as long as the 

 achenium; sty. 3-cleft; ach. brown, shining. Bogs, Cumberland, R. I., Olney ! 

 Del. to Ga. It strikingly resembles Equisetum hyemale. 



2. E. auADRANGULATA. R. Br. (Scirpus. Michx.) 



St. 2 4f high, acutely and unequally quadrangular, the broadest side 

 convex, the others concave ; sheaths radical, purplish ; spike I' or more in length ; 

 gluw^s roundish-ovate, obtuse, coriaceous ; bristles 6 ; ach. obovate, of a dull 

 white. Penn., Md., Dr. Robbins, to Ga. and La. In swamps and inundated 

 banks. 



3. E. ROBBINSII. Oakes. Robbins' Club Rush. 



Sts. clustered, 9 25' high, rigid, sharply triangular, pale green, several 

 of them fruitless ; sheath truncate ; spike 3 12" long, scarcely thicker than the 

 stem, placed 2 5" below its apex ! glumes 3 9, linear-lanceolate, acute, finally 

 brownish ; bristles 6, twice longer than the achenium; ach. I" long, pale brown ; 

 tubercle closely sessile. Ponds and ditches, N. H. and Mass., Richard I Very 

 distinct. In water a part of the stems are floating and as fine as hairs. July. 

 Spike ovate, length less than three times the diameter. * Stems terete. 



4. E. PALUSTRIS. R. Br. (Scirpus. Linn.} Marsh Club Rush. 



St. leafless, round, inflated ; spikelets smooth and shining, lance-oblong, 

 acute, often oblique, terminal ; glumes subacute, the lower ones larger, some- 

 times empty. Low grounds, U. S. and Brit. Am. Root creeping. Stems nu- 

 merous, 1 2f high, each with an obtuse sheath at the base. Achenium round- 

 ish-obovoid, rugose, punctate, surrounded with 3 or 4 scabrous bristles, and 

 crowned with a tubercle. July. 



5. E. OBTUSA. Schultes. (Scirpus obtusus. WUld. Scirpus capitatus. Walt.') 

 St. sulcate, subterete, 615' high ; spikelet ovoid, very obtuse, often near- 

 ly globose ; glumes round, dark brown, with whitish margins ; ach. obovate, 

 compressed, smooth, brown, invested with 6 setae as long as the glumes. Shal- 

 low waters, Can. and U. S., common. July. 



6. E. TUBERCULOSA. R. Br. (Scirpus. Michx.} 



St. columnar, striate, 12' high, leafless, sheathed at base ; spikelet ovate- 

 lanceolate ; glumes very obtuse, loose ; ach. somewhat triquetrous, smaller than 

 the sagittate tubercle with which it is crowned ; bristles 6, as long as the tuber- 

 cle. Sandy swamps, N. Eng. ! to Flor. Remarkable for its large tubercle. Jl. 

 * * Stems compressed or angular. 



7. E. OLIVACEA. Torr. 



Sts. caespitose, 2 4' high, slender, compressed, sulcate, soft ; spike ovate, 

 acutish 2 3" long, 20 30-flowered ; glumes ovate, obtuse, reddish-brown, with 

 scarious edges and a green midvein, the lowest largest ; bristles 6 ; sty. 2-cleft ; 

 ach. broadly obovate, smooth, of a dull, blackish-olive color when ripe. Sands, 

 generally partly submersed, Providence, R. I., Olney! Mass, to N. J. 



8. E. INTERMEDIA. Schultes. (Scirpus. Muhl.} Turf Club Rush. 



St. csespitose^ setaceous, diffuse, compressed, furrowed, hard and wiry, 



