CYPERACEAE 



179 



Lowest bract much shorter, or none; spikes several-many 

 flowered. 



Glaucous; leaves 2-4 mm. wide; spikes many-flowered. 



Not glaucous; leaves 1-2.5 n lm - wide; spikes fewer- 

 flowered. 



8. Deweyanae. 

 Spikes oblong-ovoid; perigynia nerveless or nearly so, 



sharply margined above. 

 Spikes linear; perigynia noticeably or strongly nerved, little 

 margined above. 



9. Stellulatae. 



Spike one (rarely with a small additional one). 

 Spike more than one. 



Perigynia broadest near the base, the beak serrulate. 

 Perigynia beak \i~ x A the length of body, the teeth 

 very short; scales very obtuse to acutish. 

 Leaves flat, 1-2 mm. wide, usually shorter than 



the culm; perigynia little nerved. 

 Leaves usually involute, 0.5-1 mm. wide, usually 

 exceeding the culm; perigynia strongly nerved. 

 Perigynia beak longer, strongly bi-dentate; scales 

 sharper. 

 Purely staminate spikes abundant; culms black- 

 ish at base, very rough; perigynia setu- 

 lose-serrate. 



Spikes gynaecandrous or pistillate; culms not 

 blackish at base; perigynia serrate. 

 Perigynia body lanceolate to broadly ovate, 

 usually inconspicuously nerved on inner 

 face. 

 Perigynia body suborbicular, abruptly con- 

 tracted into beak, conspicuously nerved 

 on inner face. 



Perigynia lightly nerved on both faces; 

 leaves usually less than 2 mm. wide; 

 culms slenders, harply triangular. 

 Perigynia strongly nerved on both faces; 

 scales acutish to acute; leaves 2-4 

 mm. wide, culm obtusely triangular. 

 Perigynia broadest near the middle, the beak smooth. 



10. Ovales. 



Perigynia subulate, at least 3 times as long as wide; the 



wing near base almost obsolete. 

 Perigynia lanceolate to reniform; the wing always promi- 

 nent. 

 Perigynia narrowly to broadly lanceolate, at least 2^/2 

 times as long as broad; tips of perigynia promi- 

 nently exceeding scales. 

 Leaves at most 3 mm. wide, those of sterile shoots, 



few, ascending. 

 Leaves broader, those of sterile shoots numerous, 

 spreading. 



22. C. canescens. 



23. C. brunnescens. 



24. C. Deweyana. 



25. C. bromoides. 



26. C. exilis. 



27. C. interior. 



28. C. Howei. 



29. C. sterilis. 



30. C. cephalantha. 



34. C.^Crawfordii. 



35. C. scoparia. 



