586 CYPERACE^. (sedge FAMILY.) 



brown ; achene orbicular-obovate, margined, narrowed at base, about as long 



as the awl-shaped beak ; bristles twice longer, stout, barbed downward and 



sometimes also upward. — Sandy swamps. Long Island to N. J. and Fla. 



§2. CEEATOSCHCENUS. Spikelets lanceolate, acuminate, in fruit Jlattish, 



cymose-panicled , of only one perfect and 1-4 staminate flowers ; scales fe^o ; 



bristles rigid, minutely scabrous upward ; style simple or barely 2-toothed, 



filiform and gradually thickened downicard, in fruit persistent as an exserted, 



slender-awl-shaped, upwardly roughened beak, several times longer than the 



smooth fat obovate achene ; coarse perennials ; spikelets in flower Af' , in fruit 



including the projectitig beak about 1' long. 



13. R. corniculata, Gray. (Horned Rush.) Culm 3 - 6° high ; leaves 

 about 6'' wide ; cymes decompound, diffuse ; bristles awl-shaped, stout, unequal, 

 shorter than the achene. — Wet places, Penn. to Fla., west to S. Ind. and Mo. 



14. R. macrostachya, Torr. (PI. 4, fig. l-4.) Cymes decompound, 

 or in the northern form somewhat simple and smaller, and the spikelets usually 

 more clustered; bristles capillary, twice the length of the achene. — Borders of 

 ponds, Mass. to X. J. and Fla. ; rare. 



14. CLADIUM, P.Browne. Twig-Rush. (PI. 5.) 



Spikelets ovoid or oblong, of several loosely imbricated scales ; the lower 

 empty, one or two above bearing a staminate or imperfect flower ; the terminal 

 flower perfect and fertile. Perianth none. Stamens 2. Style 2-3-cleft, de- 

 ciduous. Achene ovoid or globular, somewhat corky at the summit, or pointed, 

 without any tubercle, in wliich it differs from Rhynchospora. (Diminutive of 

 kAo'Sos, a branch, from tlie repeatedly branched cyme of the original species.) 



I. C. maris COldes, Torr. Perennial; culm obscurely triangular ( 1 - 2° 

 high) ; leaves narrow, channelled, scarcely rough-margined ; cymes small; tht^ 

 spikelets clustered in heads 3-8 together on 2-4 peduncles; style 3-cleft. — 

 Bogs, N. Scotia to Del., west to S. Minn, and Iowa. July. 



15. SCLERIA, Berg. Nut-Rush. (PI. 5.) 



Flowers monoecious ; the fertile spikelets l-flowered, usually intermixed with 

 clusters of few-flowered staminate spikelets. Scales loosely imbricated, the 

 lower empty. Stamens 1-3. Style 3-cleft. Achene globular, stony, bony, 

 or enamel-like in texture. Bristles, etc., none. Perennials, witli triangular 

 leafy culms, mostly from creeping rootstocks ; flowering in summer ; all in 

 low ground or swamps. Inflorescence, in our species, of terminal and axillary 

 clusters, the lower clusters usually peduncled. (Name, cKXripia, hardness, from 

 the indurated fruit.) 



* Achene smooth. 



1. S. triglomerata, Michx. Culm (l-|-3° high) and broadly linear 

 leaves roughish ; fascicles of spikelets few, the lowest peduncled, the upper 

 someivhat in threes; achene ovate-globose or depressed, on an obscure crusta- 

 ceous disk. — Mass. and Vt. to Fla., west to Minn, and Tex. — Yar. gracilis, 

 Britton, Culms slender (1 - 2° long) ; fascicles few-flowered, the lower (2 - 

 3-flowered) on very long filiform peduncles; achene not more than half as 

 large, acutish. — N. J. 



