CYPERACE^E, (SEDGE FAMILY.) 513 



* # * * Per 'gynia sessile, plano-convex, compressed, more or less margined, mem- 

 branaceous, with a rather short and rough (or wholly smooth in No. 26)* 

 2-toothed beak, spreading and green at maturity: scales of the fertile spikes 

 tawny cr white: bracts bristle-shaped, commonly shorter than the culm. 



22. C. sparganioides, Muhl. Spikes 6-10, ovoid; the upper ones ag- 

 gregated, the lower distinct and more or less distant ; periyynia broadly-ovate, nerveless, 

 rough on the narrow margin, about twice the length of the ovate-pointed scale ; 

 achenium roundish -ovate ; style short, tumid at the base, Var. CEPHALOfDEA is a 

 reduced state, with 4-6 rather smaller spikes, closely aggregated into an oblong 

 head; resembling No. 23 in general appearance. (C. cephalophora, var. cepha- 

 loidea, C. cephaloidea, Dew.) Low rich grounds; not rare: the var. in 

 fields and hedges. A robust species, with rather wide pale-green leaves ; some- 

 times with 1 - 2 short branches of a few spikes each at the base of the compound 

 spike (probably C. divulsa, Pursh, not of Goodenough). 



23. C. cephal6phora, Muhl. Spikes 5-6, small, and densely aggregat- 

 ed in a short ovoid head; perigynia broadly ovate, with 3-4 indistinct nerves' on the 

 outer side, scarcely longer than the ovate roughly-pointed scale ; achenium and 

 style as in the last. (C. Leavenworthii, Dew.) Woods and fields ; common. 



24. C. ftluhlenbergii, Schk. Spikes 5-7, closely approximate, forming 

 an oblong head ; perigynia orbicular-ovate, with a very short beak, prominently nerved 

 on both sides, about the length of the ovate roughly-pointed scale; achenium or- 

 bicular, with a very short bulbous style. Fields ; rather common, especially south- 

 ward. Plant 12' - 18' high, pale green, commonly with a bract at the base of 

 each spike. 



25. C. rosea, Schk. Spikes 4-6, the 2 uppermost approximate, the others 

 all distinct, and the lowest often remote; perigynia oblong (about 8-10 in each 

 spike), narrow at the base, widely diverging at maturity, twice as long as the 

 broadly ovate obtuse scale. Varies with weak slender culms, and small 3 - 4-flow- 

 ered spikes. (Var. RADIATA, Dew. C. neglecta, Tuckerman.) Moist woods 

 and meadows ; common. 



26. C. retroflexa, Muhl. Spikes 4-5, all approximate, the 1-2 lowest 

 distinct but not remote ; perigynia (about 5-7 in each spike) ovate, or ovate-Ian' 

 ceolate, smooth on the margin and beak, not much exceeding the ovate-lanceolate pointeft 

 scale, widely spreading or reflexed at maturity. (C. rosea, var. retroflexa, Torr, t 

 Cyp. ) Copses and moist meadows ; less common than the last, from which it 

 is distinguished by the smaller approximate spikes, longer and sharper scales, 

 and especially, from every species in this subsection, by the smooth margin and 

 beak of the perigynium. 



* # # # * Perigynia plano-convex, without a beak, of a thick and leathery texture, 

 prominently nerved, smooth (except on the angles), with a minute and entire 

 or slightly notched white membranaceous point : achenium conformed to the peri- 

 gynium, crowned with the short thick style : bracts like the scales (brown), 

 the lowest with a prolonged point : rootstock creeping. CHORDORH!Z^E. 



27. C. Chordorlliza, Ehrh. Culms branching from the long creeping root- 

 stock (4' -9' high), smooth and naked above, clothed at the base with short ap- 



