366 CYPERACE^. (sedge FAMILl.) 



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

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



1. C. aristatus, Rcttb. Spikes oblong becoming linear, 7 to 13-flowered, 

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

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

 drying. Across the continent. 



* * Stamens 3 : spikes loosely or somewhat remotely 6 to X'i-fiowered, 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. S C I R P U S, 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 iu 

 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, smcdl, of en flattish : akene triangular, smooth. 



1. S. esespitosus, 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. 



.,_ H_ Spikes clustered {rarely only one), appearing lateral from the one-leaved 



involuae, 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 rusty brown, closely sessile in one cluster. 



2. S. pun gens, 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 oetween the acute lobes : anthers tipped with 

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

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



