208 



CYPERACEAE (SEDGE FAMILY) 



C. norvegica. 



39. C. glareosa. 

 glareosa, v. amphigena. 



40. O. tenella. 



41. C. rosea. 



(41) C. rosea, v. radiata. 



(41) C. rosea, v. minor. 



C. retroflexa. 



43. C. muricata. 



44. 



C. Muhlenhergii. 



enervi 



Spikes distinct; the lowest 4-5 mm. thick; the ter- 

 minal 1-1.8 cm. long-; perigynia 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 ; 

 perigynia pale brown or drab. 



Perigynia fusiform 



Periervnia ovoid (39) C 



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

 }r. Perigynia ellipsoid-ovoid, scarcely compressed, nearly terete 

 k. Perigvnia compressed I. 



L Spikes 2 or more in a simple or compound spicate or paniculate 



inflorescence m. 

 m. Eootstocks 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. 

 0. 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. 



Perigvnia ovoid 



Perigynia lance-subulate .... (42) C. retroflexa, v. texensis 



p. Perigvnia of essentially uniform (membranous) texture 



throughout, not conspicuously spongy below the 



middle ; margins slightly if at all inflexed /•. 



r. Perigynia 4-6 mm. long 



r. Perigynia less than 4 mm. long s. 



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

 1.5)— 4 cm. long. 



Perigynia distinctly nerved 



Perigynia nerveless .... (44) C. Muhlenbergi 



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

 cm. long. 

 Perigynia elliptic-ovate, broadest below the 

 middle, narrowest at base .... 

 Perigynia cordate-deltoid, broadest at the cor- 

 date or subcordate base .... 

 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 moniliform inflorescence . 

 w. Perigynia wing-margined only above the middle ; 

 spikes approximate in a cylindric or ovoid head. 

 Perigvnia broad-ovate to suborbicular, nearly 

 equaled by the long-pointed scales. 

 Culms 2-5 dm. high ; leaves subbasul ... 



Culms 6-12 dm. high; leaves remote . . (50) C. gravida, v. laxifolia. 

 Perigvnia lance-ovate, twice as long as the thin 



white scale 48. C cepkaloidea 



t. Perigynia spongy below the middle, the outer face 



[.rominently ribbed 55, C. conjuncta. 



n. Spikes yellowish or tawny when mature T. 



V. Perigvnia firm and uniform in texture, not spongy nor 

 "conspicuously inflated below, the beak shorter than 

 or barely equaling the body ^c. 

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

 inner face x. 

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

 ered ; scales acuminate, rarely awned y. 

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



wing-margins 43. (7. muricata. 



y. Leaves 4-S mm. wide ; culms soft, with almost wing- 

 like angles. 

 Beak nearly as long as the narrow-ovate body 



of the perigynium 



Beak one third as long as the broad-ovate or sub- 

 orbicular body of the perigynium. 

 Culms 2-5 dm. high ; leaves subbasal 

 Culms 6-12 dm. high ; leaves remote (50) 



OJ. Membranous or chartaceous band of the ieaf-sheath 

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



45. C. cephalophora. 



46. C. Leavenworthii. 



47. C. sparganoides. 



50. C. gravida. 



C. alopecoidea. 



50. C. gravida. 



C. gravida, v. laxifolia. 



