cyperacejE. (sedge family.) 557 



I. H. SUbsquarrdsa, Nees. Dwarf or minute annual (l'-5' high); 

 involucre l-leaved, as if a continuation of the bristle-like culm, and usually with 

 another minute leaf; spikes 2-3 (barely 2" long) ; scales brown, tipped with a 

 short recurved point. (Seirpus subsquarrosus, Muhl.) — Sandy borders of 

 ponds and rivers; often growing with Cyperus inflexus. July -Sept. — Var. 

 DiiiMMoxuii (II. Drummondii, iVees.) is a form with single and paler or green- 

 ish heads : Illinois and southward. 



7. ELEOCHARIS, R.Br. Spike-Rush. (PI. 3.) 



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 triangular achenium. — Leafless, 

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

 ing rootstocks : flowering in summer. (Name from e'Xos, a marsh, and x ai P a < 

 to delight in; being marsh plants.) 



§ 1. Spike terete, hardly if at all thicker than the spongy-cellular culm; the scales 

 firmly persistent: style mostly 3-clejl : bristles of the perianth 6 (rarely 7), firm 

 or rigid, mostly barbed downwardly, and equalling or surpassing the triangular or 

 double convex achenium. 



* Spike linear or lanceolate-awl-shaped, few-flowered; the scales (only 3 - 9) few- 



ranked, convolute-clasping the long flattened joints of the axis, lanceolate, herba- 

 ceous (green) and several-nerved on the back, and with thin scarious margins. 



1. E. Robbinsii, Oakes. Flower-bearing culms exactly triangular, rather 

 stout, erect (8'- 2° high), also producing tufts of capillary abortive stems or 

 fine leaves, which float in the water ; sheath obliquely truncate ; achenium ob- 

 long-obovate, triangular, minutely reticulated, about half the length of the 

 bristles, tipped with a flattened awl-shaped tubercle. — Shallow water, from 

 Pondicherry Pond, New Hampshire (Robbins), to New Jersey (C. E. Smith, 

 frc), and southward. — Spike varying from 4" to 10'' long, by scarcely over a 

 line wide ; the long scales rather remote and sheath-like. 



* * Spike cylindrical and many-flowered, V— 2' long ; the scales regularly imbricated 



in several ranks, firm-coriaceous with a narrow scarious margin and no midrib, 

 pale, nerveless or faintly striate : culms large and stout (2° -4° high) : sheaths at 

 the base often leaf-bearing. (Limxochloa, Nees.) 



2. E. equisetoides, Torr. Culm terete, knotted as if jointed by many cross 

 partitions ; achenium smooth, with a conical-beaked tubercle. — Shallow water, 

 Rhode Island (Olney), Michigan (Houghton), Delaware, and southward. 



3. E. quadrangulata, R. Br. Culm continuous and sharply 4-angled ; 

 achenium finely reticulated, with a conical flattened distinct tubercle. — Shallow 

 water, New York (outlet of Oneida Lake, A. U. Curtiss) to Michigan and 

 southward : rare. 



§ 2. Spike terete and turgid-ovate, very much thicker than the slender culm ; the scales 

 thin<oriaceous or firm-membranaceous and persistent, ovate: style 3<lefl : bristles 



