166 NEW YORK STATE MUSEUM 



This species is easily distinguished by its three or four short 

 thick erect contiguous spikes, at first pale green but turning 

 brownish when old. 



54. Carex virescens Muhl. 



Stems 12-30' high, slender, erect or sometimes spreading, 

 rough near the summit; leaves pubescent, I'-l^" wide, mostly 

 tapering to a long filiform point, often equaling the culm ; spikes 

 2-5, the highest staminate at the base, all approximate or con- 

 tiguous, ovoid or oblong, 4"-12" in length, about 2" thick, com- 

 pactly flowered, all on short stalks, the lowest sometimes 

 spreading; bracts leafy or filiform, the lowest exceeding the 

 culm ; perigynia ovate prominently nerved, scabrous-pubescent, 

 longer than, or equaling the ovate, mucronate scale. 



Similar to C. triceps in its place of growth and time of maturity. 

 It is separated from it by the narrower and often longer spikes, 

 and by its hairy perigynia. 



Var. costata Dew. Stems 20-30' high, spikes cylmdrical, erect 

 or slightly spreading ; perigynia strongly nerved or ribbed. 

 Equally common with the type. 



Terminal spike pistillate at the summit, staminate below; 

 fertile spikes 3-5, linear or cylindrical, on short, erect or long 

 filiform peduncles, approximate, or the lowest sometimes distant, 

 subdensely or loosely flowered ; perigynia oblong with a short, 

 notched point, or obtuse and pointless. 



Spikes narrowly cylindrical, less than 2" wide 1 



Spikes broadly cylindrical, 2" wide . 2 



1 Spikes loosely flowered, perigynia acute aestivalis. 



1 Spikes densely flowered, perigynia obtuse gracillima. 



2 Scale shorter than the perigynium f ormosa . 



2 Scale as long as the perigynium Davisii. 



55. Carex aestivalis M. A. Curtis. 

 Stems l°-2° high, slender, erect or spreading, rough above the 

 middle ; leaves mostly shorter than the culm, I'-l^" wide, sparsely 

 hairy, bright green, sheaths pubescent ; staminate spike fertile at 

 the summit, linear or clavate ; pistillate spikes 3-i, linear, erect or 

 spreading, the upper 2 or 3 approximate, the uppermost some- 

 times sessile at the base of the staminate, the others short-stalked. 



II 



