388 CYPERACE^E. (SEDGE FAMILY.) 



spikes 2 to 5, erect, sessile, or the lowest very shortly ped uncled, distinct, 

 usually more or less remote, glaucous-purple : perigynium elliptic, glaucous, 

 nerved, rough-granular, contracted into a short emarginate or entire beak. 

 Bogs throughout, but evidently nowhere common. The terminal spike is 

 rarely all staminate. The lower leaf sheaths are purple and at length fibril- 

 lose. (Eu.) 



*- -*- Scales broad, not conspicuously acute. 



50. C. atrata, L. Cespitose : culm 6 inches to 2 feet high, sharply angled, 

 smooth or roughish, longer than the long-pointed leaves: bracts about equal- 

 ling the culm, mostly with conspicuous auricles : spikes 2 to 4, densely flow- 

 ered, clavate or oblong, thick, to l inches long, black or dark brown, 

 approximate or often aggregated, all more or less peduncled, at first upright or 

 spreading, at length usually drooping and often exserted, and the top of the culm 

 appearing as if bent over : perigynium broadly ovate or orbicular, nerveless, bearing 

 a short notched beak, commonly a little broader and about the length or a little 

 shorter than the black or dark brown obtuse or acutish scale. Varies much : the 

 spikes are sometimes more or less erect at maturity, the upper spike is rarely 

 all staminate, and the upper scales are often acuminate but never awned. 

 High mountains, Colorado and Utah and northward. (Eu.) 



Var. nigra, Boott. Spikes short, about as broad as long, densely aggregated 

 and capitate, sessile, erect : midnerve of the scale generally projecting into a short 

 cusp: perigi/nium usually scabrous. C. nigra, All. With the last. (Eu.) 



Var. OVata, Boott. Resembling the drooping or open forms of the spe- 

 cies, but the spikes more slender, the whitish or green perigynium conspicuously 

 broader and mostly longer than the brown scale, giving to the graceful spikes a 

 conspicuous light and dark appearance. C. ovata, Rudge. Colorado, Utah, 

 and southward. 



Var. erecta, W. Boott. Like the last, but the spikes erect, short, sessile or 

 nearly so, and the staminate scales narrow. Nevada and westward ; probably 

 in our region. 



51. C. alpina, Swartz. Culms very slender, 6 inches to 2 feet high, smooth, 

 longer than the narrow leaves: spikes 2 to 4, small (J inch and less long), 

 mostly compactly flowered, black or black and green, closely aggregated, erect and 

 capitate, the lowest very short-stalked and usually subtended by a green bract: 

 perigynium ovate or elliptic, obscurely nerved or nerveless, with a short slightly 

 notched beak, green or fuscous, commonly a little longer than the ovate, black, 

 nearly obtuse scale. C. Vahlii, Schk. High mountains, South Park, Colo- 

 rado, and northward. A delicate species, distinguished from erect forms of 

 the preceding species by its slender naked culm, and small, nearly globular 

 spikes. 



SUBGENUS II. Vignea. Staminate flowers few and inconspicuous, borne 

 at the base or apex of the pistillate spikes. Pistillate flowers in short, 

 sessile spikes (spike single in Nos. 52 and 53), which are commonly more or 

 less aggregated into heads, or even panicled. Cross-section of the perigynium 

 plano-convex in outline. Styles two and achenium lenticular. The spikes, 

 and especially the terminal one, usually have contracted bases when the stami- 

 nate flowers are borne below, and empty scales at the top when the staminate 

 flowers are borne above. 



