CYPERACE.E. (SEDGE FAMILY.; 495 



1. D. SpathjkceilHl, Pers. Borders of ponds; common. July - 

 Sept. 



4. HEMICARPHA, Nees. HEMICARPHA. 



Spikes many-flowered, ovoid, one or few in a lateral cluster, sessile. Scales 

 regularly imbricated in many ranks, ovate or obovate. Inner scale single be- 

 hind the flower, very thin, finally often adhering to or wrapped around the ob- 

 long or obovoid pointless naked achenium. Perianth none. Stamen 1. Style 

 2-cleft. Little tufted annuals resembling Scirpus, except as to the minute inner 

 scale, which is readily overlooked ; the naked culms with bristle-like leaves at 

 the base. (Name from 77/^11, half, and icdpcpos, straw or chaff, in allusion to the 

 single inner scalelet on one side of the flower.) 



1. H. subsquarrosa, Nees. Dwarf (!'- 4' high); involucre 1 -leaved, 

 as if a continuation of the bristle-like culm, and usually with another minute 

 leaf; spikes 2-3 (2" long); scales brown, tipped with a short recurved point. 

 (Scirpus subsquarrosus, Muhl.) Sandy borders of ponds and rivers ; not rare, 

 often growing with Cyperus inflexus. July. Var. DnuMM6NDii (H. Drum- 

 mondii, Nees) is a form with single and pale or greenish heads. Illinois and 

 southward. 



5. ELEOCHARIS, R. Brown. SPIKE-RUSH. 



Spike single, terminating the naked culm, many - several-flowered. Scales 

 imbricated all round in many, rarely in 2 or 3, ranks. Perianth of 3-12 (com- 

 monly 6) bristles, usually rough or barbed downwards, rarely obsolete. Sta- 

 mens 3. Style 2 - 3-cleft, its bulbous base persistent as a tubercle, which is 

 jointed with the apex of the lenticular or obtusely triangular achenium. Leaf- 

 less, chiefly perennial, with tufted culms sheathed at the base, from matted or 

 creeping rootstocks. (Name from eXos, a marsh, and ^ai'pco, to delight in ; being 

 marsh plants.) 



$ 1. LIMN6CHLOA, Nees. Scales of the dense and terete many-flowered spike 

 papery-coriaceous and rounded, with a scarious margin, pale : style 3-cleJl : ache- 

 nium doubly convex, about equalling the bristles. 



* Culms large and stout, often thicker than the cylindrical spike: scales faintly many- 

 strinte, and densely imbricated so as usually to form (Jive) distinct spiral rows : 

 sheaths at the base often nearly leaf-bearing. (LiMNOCHLOA proper.) 



1. E. eqilisetOldes, Torr. Culm terete, knotted as if jointed by mtir/ 

 cross partitions (2 high, thick as a goosequill) ; achenium smooth, crowned with 

 a conical-beaked tubercle. Shallow water, Rhode Island (Olncy), Michigan 

 (Houyhton}, Delaware, and southward. Spike 1' or more long. 



2. E. qiiadranglllata, R, Brown. Culm even, sharply 4-angled (2- 

 4 high) ; achenium finely reticulated, crowned with a conical flattened distinct 

 tubercle. Penn., Michigan, and southward. 



* * Culms slender : spike ovate or oblong : scales ivith a midrib. 



3. E. tllberctllosa, R. Brown. Culms striate (8' -12' righ); bristles 

 strongl v barbed downward ; ach&fiiitm triangular, ribbed and minutely reticulated, 



