208 



CYPERACEAE (SEDGE FAMILY) 



Spikes distinct; the lowest t-:> mm. thick; the tcr- 

 iniiiiil 1-1.8 ctn. long; pi'rigynia pale, about equaled 

 by the yellowish-brown blunt scales .... 



Spikes approximate : the lowest less than 4 mm. thick; 

 plant weak, lax ; leaves involute, 0.5-1.5 mm. broad ; 

 perigvnia pale brown or drab. 

 Pcrigynia fusiform 



( '. 



41. C. rosea. 



(41) C. roxcd, v. rintiatii. 



(41) C. rosed, v. ininnr. 



42. C. retrofit 



IVrigvnia ovoid ...... (^9) C 1 - fffaPGoitt, v. 



A . Staminate flowers borne at the top of the spikes k. 



k. IVrigvnia ellipsoid-ovoid, scarcely compressed, nearly terete . 40. C.leiiel/d. 



k. Perigynia compressed I. 



I. Spikes 2 or more in a simple or compound spicate or paniculate 



inflorescence m. 



m. Rootstocks short and thick ; culms in terminal tufts or stools n. 

 n. Spikes green or nearly so when mature (becoming brown 



only when over-ripe) o. 

 o. Broadest leaves 1-4.5 mm. wide p. 

 p. Perigynia very spongy below the middle, the nerve-like 



margins inflexed q. 

 q. Perigynia with minutely serrulate margins ; scales 



blunt ; spikes mostly remote. 

 Perigynia quickly becoming squarrose. 

 Culms erect ; spikes 6-15-flowered 

 Culms loosely spreading ; spikes 2-6-flowered 



Perigynia ascending in fruit 



q. Perigynia with smooth margins ; scales acuminate ; 

 spikes mostly approximate. 



Perigynia ovoid 



Perigynia lance-subulate .... (42) C. retrojlexa, v. 

 p. Perigynia of essentially uniform (membranous) texture 

 throughout, not conspicuously spongy below the 

 middle ; margins slightly if at all inflexed r. 



r. Perigynia 4-6 mm. long 4:?. C. 



r. Perigynia less than 4 mm. long . 



s. Leaves and culms stiff and wiry ; heads 2 (rarely 

 1.5) 4 cm. long. 



Perigynia distinctly nerved 44. r. 



Perigynia nerveless .... (44) C. Muhlenberyii, \. < "//, ///*. 

 . Leaves and culms soft; heads 0.7-1.5 (rarely 1.8) 



cm. long. 

 Perigynia elliptic-ovate, broadest below the 



middle, narrowest at base . ; . . 45. C. cephalophum. 

 Perigynia cordate-deltoid, broadest at the cor- 

 date or subcordate base . . . .46. C. Leavenwortltii. 

 o. Leaves 5-10 (the narrowest rarely 4.5) mm. wide t. 



t. Perigynia uniformly firm throughout, the outer face 



nerveless or very faintly nerved u. 

 u. Perigynia wing-margined to the base; spikes mostly 



distinct in a moniliforrn inflorescence . . .47. C. xptiryanoides. 

 11. Perigynia wing-margined only above the middle ; 



spikes approximate in a cylindric or ovoid head. 

 Perigynia broad-ovate to suborbicular, nearly 



equaled by the long-pointed scales. 

 Culms 2-5 dm. high ; leaves subbasal . 

 Culms 6-12 dm. high ; leaves remote 

 . Perigynia lance-ovate, twice as long as the 



white scale 



t. Perigynia spongy below the middle, the outer face 



prominently ribbed 



. Spikes yellowish or tawny when mature T. 

 . v. Perigynia firm and uniform in texture, not spongy nor 

 "conspicuously inflated below, the beak shorter than 

 or barely equaling the body w. 

 w. Perigynia straw-color, thin, distinctly flattened on the 



inner face 05. 



. Membranous band of the leaf-sheath not cross-puck- 

 ered ; scales acuminate, rarely awned //. 

 y. Leaves 2-3 mm. wide ; culms linn, without thin 



wing-margins 



y. Leaves 4-8 mm. wide ; culms soft, with almost win.ir- 



like angles. 

 Beak nearly as long as the narrow ovate body 



of the pcrigynium 



Beak one third M lonir as the broad-ovate or sub 



orbicular body of the pcrigynium. 

 Culms '2 "> dm. \\\\i\\ ; leaves subbasal 

 Culms Ci-l-J dm. hitrh ; lea\e> rem..tc (50) C. 



<f. Membranous or chartacecms band of the loaf-sheath 

 cross-puckered, at least in age ; scales awn-tipped. 



. 50. C. yntriiln. 

 . (50) C. grarii/n. v. 

 thin 



48. C. cephaloidea. 



55. C. conjunct^. 



4:?. (\ 



i '. 



."(I. < '. 



grit r i,l, i. v. t,urifoliti. 



