CYPERACE^E. (SEDGE FAMILY.) 495 



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

 Sept. 



4. II JEM I CARPI! A, Nees. HJSMICABPHA. 



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 rjfu, half, and <dp(j)os, straw or chaff, in allusion to the 

 single inner scalelet on one side of the flower.) 



1. H. Sllbsquarrosa, 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. DRUMMONDII (H. Drum- 

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

 southward. 



5. 131. HOC Iff A It IS, 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 eXor, a marsh, and x at/ P a) 5 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-cleft : ache- 

 nium doubly convex, about equalling the bristles. 



# Culms large and stout, often thicker than the cylindrical spike: scales faintly many' 

 striate, and densely imbricated so as usually to form (five) distinct spiral roivs : 

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



1. E. eqilisetOldes, 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. 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 with a midrib. 



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

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



