CYPERACE^E. (SEDGE FAMILY.) 385 



ribbed, dilate (laciniate) scale. Provost River, N. Utah (Sereno Watson; an 

 ambiguous specimen). The leaves usually dry, stiff and hard. The lowest 

 bract is often very much prolonged. 



42. C. aquatilis, Wahl. Stoloniferous : culm obtusely angled, 2 to 3 feet 

 high, smooth, leafy : leaves flat, pale, scarcely longer than the culm : pistillate 

 spikes 2 to 4, erect, thick and compactly flowered throughout or more commonly 

 inclining to club-shaped with a gradually attenuated base, the upper sessile, the 

 lower more or less peduncled and often long-exserted : perigynium broadly 

 elliptic or obovate, rarely circular, nerveless, tipped with a minute and entire point, 

 green or light-colored, wider and either longer or shorter than the green or purple- 

 margined acutish scale. Wyoming ( W. Boott) ; probably generally distrib- 

 uted. A large species in wet places, readily distinguished from the next by 

 its stout and leafy smooth culms, wide and amplectant bracts, and thick 

 spikes. (Eu.) 



Var. sphagnophila, Anders. Slender, 8 to 16 inches high: leaves very 

 narrow, long-pointed : spikes slender, very loosely flowered and long-attenuated 

 below, the lower peduncles slender and flexuose : perigynium about the width of 

 or a little ivider than the dark purple scale. C. aquatilis, var. minor, Boott. 

 C. borealis, Lange. C. personata, Olney. Twin Lakes, Colorado (John Wolfe) ; 

 also in British America. (Eu.) 



C. LENTICULARIS, Michx., may be expected northward. It may be dis- 

 tinguished from C. aquatilis by its smaller size, narrower spikes the terminal 

 one of which is pistillate at the top, and the nerved perigynium. 



*- *- Low or tall and slender species: bracts mostly short and narrow, often 

 setaceous (rarely long in Nos. 42 and 43). 



w- Culms slender and tall (2 feet or more high) : leaves with more or less revolute 

 margins when dry. 



43. C. Stricta, Lam. Densely cespitose, forming high tussocks in wet places : 

 culms 2 to 5 feet high, sharply angled, rough, leafy only at the base, longer than 

 the narrow and long-pointed carinate leaves, when full grown surrounded below 

 by the conspicuous reticulated fibrous remains of the oldei- sheaths : pistillate 

 spikes 2 to 4, erect or spreading, sessile or the lower shortly peduncled and 

 sometimes loosely flowered at the base, linear, often male at the top; lower 

 spike or two often subtended by a narrow bract barely as long as the culm : 

 perigynium oval or ovate, green or light-colored, nerveless or nearly so, the point 

 entire or slightly emarginate, little broader and longer or shorter than the purple- 

 margined ascending acute or acutish scale. C. Virginiana, Smith. C. acuta, 

 Muhl., etc. C. angustata, Boott. C. xerocarpa, S. H. Wright. Colorado 

 (Brandeqee, Vasey). 



44. C. aperta, Boott, var. divaricata, Bailey. Differs from the last in 

 its smoother culm, in the absence of reticulated fibrous sheaths, and in the broader 

 perigynium which is subtended by an acute spreading scale of more than its own 

 length: bracts sometimes leaf-like. Colorado (Vasey). Differs from the 

 typical Eastern C. aperta, which may be expected in our region, in its greater 

 size, wider leaves, and looser habit, larger perigynia, and more conspicuously 

 divaricate, darker scales. 



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