366 CYPERACE.E. (SEDGE FAMILY.) 



* Stamen 1 : spikes short and small, collected in globular heads, ovate or linear- 

 oblong, compactly many-Jlowered : low annuals, with a 2 to 3-leaved involucre. 



1. C. aristatus, Rottb. Spikes oblong becoming linear, 7 to 1 3-flowered, 

 in 1 to 5 ovate heads : scales nerved, tapering into a long recurved point : 

 akene obovate, obtuse. C. inflexus, Muhl. Said to be sweet-scented in 

 drying. Across the continent. 



* # Stamens 3 : spikes loosely or somewhat remotely 6 to 12-flowered, flatfish and 



greenish, several crowded together in one sessile or in a few peduncled heads or 

 dense clusters : scales convex on the back, many-nerved, a little longer than the 

 sharply triangular akene : perennials, with hard clustered corms or bulb-like 

 tubers at the base of the stems. 



2. C. Schweinitzii, Torr. Stem rough on the angles, 1 to 2 feet high : 

 leaves linear: umbel simple, 4 to 8-rayed : spikes crowded along the Upper 

 part of the mostly elongated rays, erect : scales awl-pointed : joints of the axis 

 narrowly-winged. In dry sandy places in Colorado ; also from Lake Ontario 

 northwestward. 



3. C. filiculmis, Vahl. Stem slender, wiry, often reclined: leaves linear: 

 spikes numerous and clustered in one sessile dense head, or in 1 to 7 additional 

 looser heads on spreading rays of an irregular umbel : joints of the axis naked : 

 scales blunt, greenish. In dry soil, and coming into our range from W. 

 Kansas. 



2. SCIRPUS, L. BULRUSH or CLUB-RUSH. 



Hypogynous bristles 3 to 6, barbed or ciliate, or wanting. Style 2 to 3-cleft. 

 Akene lenticular or more or less triangular, obovoid. Tufted plants, with 

 creeping rootstocks, the stem sheathed or leafy at base, and the spikelets in 

 an apparently lateral cluster, or compound umbel-like panicle, or solitary. 



* Bristles when present rigid, not elongated and contorted or exserted after flower- 



ing, barbed downwards or smooth. 

 - Spike solitary, few-flowered, small, often flatfish : akene triangular, smooth. 



1. S. CSBSpitOSllS, L. Stems terete, filiform, in compact turfy tufts, 

 densely sheathed at the base, the upper sheath bearing a very short awl- 

 shaped leaf : scales of the ovoid spike rust-colored : involucral bract a rigid- 

 pointed scale, resembling the lowest proper scale of the spike : bristles 6, 

 smooth, longer than the abruptly short-pointed akene. Mountains of Colo- 

 rado (Hall and Harbour) also from the mountains of New England and 

 N. Carolina northwestward. 



4_ ^_ Spikes clustered (rarely only one), appearing lateral from the one-leaved 



involucre, which resembles the naked stem, seeming to be a continuation of it. 



w. Stem sharply triangular, stout : sheaths at base more or less leaf-bearing : 



spikes rust i/ brown, closely sessile in one cluster. 



2. S. pungens, Vahl. Stem sharply 3-angled throughout, 1 to 4 feet high, 

 with concave sides: leaves I to 3 elongated : spikes 1 to 6, capitate, usually long 

 overtopped by the pointed involucral leaf : scales ovate, sparingly ciliate, 2-cleft 

 at the apex and awl-pointed from between the acute lobes : anthers tipped with 

 an awl-shaped minutely fringed appendage. Borders of ponds and streams 

 from California into Mexico, and northward ; common in the Atlantic States. 



