CYPERACE^E. (SEDGE FAMILY.) 495 



1. I>. spatlliaceuin, Pers. Borders of ponds; common. July - 

 Sept. 



4. I3EUIICARPHA, Nees. HBMICARPHA. 



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. Stylo 

 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 jj/ii, half, and Kap<pos, straw or chaff, in allusion to the 

 single inner scalelet on one side of the flower.) 



1. H. Slibsquarrosa, Nees. Dwarf (l'-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, MahL) Sandy borders of ponds and rivers ; not rare, 

 often growing with Cyperus inflexus. July. Var. DRDMMONDII (II. Drum- 

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

 southward. 



5. EL.EOCIIARIS, R. Brown. SriKE-Rusn. 



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

 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 achcnium. Leaf- 

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

 creeping rootstocks. (Name from eXos, a marsh, and x^P^i lo delight in; being 

 marsh plants.) 



4 1. LIMN6CIILOA, Nees. Scales of the dense and terete many-flowered spikt 

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

 nium doubly convex, about equalling the bristles. 



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

 striate, and de.mdy imbricated so as usually to form (Jive) distinct spiral roics : 

 &hcatJis at tlie base often nearly leaf-bearing. (LiMNOCHLOA proper.) 



1. E. CQUisetoides, Torr. Culm terete, knotted as if jointed by many 

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

 a conical-beaked tubercle. Shallow water, Rhode Island (Olnc : y], Michigan 

 (Houghton), Delaware, and southward. Spike 1' or more long. 



2. E. qtiadrangrulata, 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 with a midrib. 



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

 strongly barbed downward ; ichenium triangular, ribbed ami minutely reticulated, 



