512 crrv.vxcv.M. (sedge family.) 



1G. C. vatJpisioidea, Michx. Spike oblong and dense, or more or less 

 Interrupted, of 8-10 crowded clusters (l^'-i4' long) ; perigynia ovate from a 

 broad base, with a more or less abrupt beak, diverging at maturity (C. multi- 

 flora, Muhl. C. bracteosa and C. polymorpha, Schw. C. microsperma, WaJd ) 



— Varies with the perigynium narrower, and the beak tapering and more 6trongly 

 serrulate. (C. setacea, Dew.) — Low meadows; very common. — Varies ex- 

 ceedingly in the size and shape of the perigynium and beak. 



# # * Perigynia on short stalks, plano-convex, without a margin, membranaceous, 

 with a thick and spongy base and a long tapering 2-toothed rough beak, distinct- 

 ly nerved (only obscurely so in No. 20 and 21 ), widely spreading and yellow at 

 maturity : spikes dense, more or less aggregated, sometimes decompound : 

 scales of the fertile spikes tawny, with a sharp point : bracts bristle-shaped, 

 shorter than the thick and triangular culms. — Vulpine. 



17. C crus-corvi, Shuttlcworth. Spike very large, decompound, the 

 lower branches long and distinct, the upper shorter and aggregated ; bracts often 

 2-toothed at the base: perigynia attenuated from an orate dilated and truncate base into 

 a very long slightly-winged beak, much exceeding the scale ; style tumid at the base. 

 (C. sicreformis, Boott. C. Halei, Dew.) — Swamps, Ohio to Wisconsin, and 

 southward. — A conspicuous, very large species, with spikes 4' -9' long, ofte.D 

 somewhat paniculate, and glaucous leaves ^' wide. 



18. C Stipata, Muhl. Spikes 10-15, aggregated, or the lower ones dis- 

 tinct and sometimes compound ; perigynia lanceolate, with a long beak tapering 

 froMa truncate base, much exceeding the scale; style not tumid at the base. (C. vul- 

 pinoidea, Ton:, Cyp., not of Michx.) — Swamps and low grounds; common. 



19. C. Vtllpina, L. Spikes numerous, aggregated into a cylindrical and 

 dense (or at times elongated and somewhat interrupted) compound spike; peri- 

 gynia compressed, tapering from a broadly-ovate base into a beak not much longer than 

 the scale ; achenium oval; style tumid at the base. — Ohio, Illinois, and Kentucky. 



— A tall, robust species, 3° -4° high, with wide leaves and a remarkably thick 

 rough culm. It is very like the last, from which it chiefly differs in the more 

 compressed and wider base and shorter beaks of the perigynia. — The forms 

 with interrupted spikes have also a general resemblance to No. 22 ; which, how- 

 ever, is distinguished by the margined and nerveless perigynia. (Eu.) 



20. C aBopecoidea, Tuckerman. Head of 8-10 aggregated spikes, 

 oblong, dense ; perigynia compressed, very obscurely nerved, ovate from a broad trun- 

 cate or somewhat heart-shaped base, a little longer than the scale ; achenium pyri- 

 form; base of the style not tumid. (C. cephalophora, var. maxima, Dtw.) — 

 Woods, W. New York to Penn., Michigan, &c — Much resembling the last, 

 but smaller, with shorter and more compact spikes ; easily distinguished by the 

 nearly nerveless perigynia, and the different achenium and style. 



21. C HBMB'icfeJa, L. Spikes 4 - 6, ovoid, approximate but distinct, the 

 lowermost sometimes a little remote ; perigynia ovate-lanceolate, somewhat com- 

 pressed, nerveless, or i<ery obscurely nerved towards the base, rather longer than the 

 scale; achenium ovate, base of the style not tumid. —Fields, Massachusetts (in- 

 troduced?), Ohio, and Kentucky; rare. — Spikes mostly looser than in the last, 

 the perigynia narrower, with a longer and more tapering beak. (Eu.) 



