CYPERACE.E. (SEDGE FAMILY.) 495 



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

 Sept. 



4. HEM I CARP II A, Nees. Hemicaepha. 



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, veiy 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 

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

 the base. (Name from l}p,i, half, and Kapcpos, straw or chaff, in allusion to the 

 single inner scalelet on one side of the flower.) 



1. H. subsquarrosa, Nees. Dwarf (1' -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. Deummondii (II. Drum- 

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

 southward. 



5. EEEOC MARIS, 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 rootstoeks. (Name from e\os, a maish, and ^alpcc, to delight in; being 

 marsh plants.) 



(f 1. LIMN6CHLOA, Nees. — Scales of the dense and terete many-flowered spike 

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

 nium doubly convex, about equalling the bristles. 



:«• Culms large and stout, of en thicker than the cylindrical spike: scales faintly many- 

 striate, and densely imbricated so as usually to form {five) distinct spiral rows : 

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



1. E. eQltisetoides, 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 (Olney), Michigan 

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



2. E. quadrangllliYta, 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 oblo?2g : scales ivith a midrib. 



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

 strongly barbed downward ; achenium triangular, ribbed and minutely reticulated, 



