207' CYPERACE.VE 



Leaf-blades 2.5 to 6 mm. wide; head interrupted, compound; perigynia 3 to 4 mm. long, dull, 



concealed by the scales 19. C. cusickii. 



9. Stenorhynchae. 

 Perigynia 3 to -t nun. long, the beak much shorter than the body; scales strongly dark-tinged. 



Leaves clustered at base ; sheaths not green and white mottled dorsally ; cubns slender 



20. C. jonesii. 

 Leaves not clustered at base, the lower blades much reduced; sheaths green and white 



mottled dorsally; culms stout 21. C. nervUui. 



Perigynia 4 to 6 mm. long, the beak about length of body; scales not or aearcely dark-tinged. 



22. C. stipata. 



10. Stellulatae. 

 Spikes more or less widely separate, not brownish-black. 



Body of perigynimn broadest near middle; beak with few weak sorrulations 



23. C. laevieuJmis. 

 Body of perigynium broadest near base; Ijeak strongly serrulate. 



Beak of perigynimn bluntly bidentate, 1,4 to % length of body, the ventral suture obso- 

 lete or inconspicuous; scale obtuse, V^ length of body of perigynium 



24. C. interior. 

 Beak of perigynium sharply bidentate, the ventral suture conspicuous. 



Beak of perigynium chestnut-bro^\^l tipped; culms obtusely triangular; pistillate 

 scales obtuse or obtusish, chestnut-brown tinged with broad shining margins 

 and apex, rounded and not keeled, the midvein obscure at apex. 

 Spikes widely separate, the terjninal long-clavate; perigynia 3.5 to 4 mm. long. 



25. C. ormantlM. 

 Spikes approximate, the terminal short-clavate ; perigynia 3.75 to 4.5 nun. long. 



26. C pltyllomaiiica. 



Beak of perigynium reildish-brown tipped; culms sharply triangular; pistillate scales 



obtusish to cuspiilatc, yellowish-brown tinged, the margins and apex narrow, 



opaque or dull whitish, keeled with the sharp midveiu which is prominent to 



apex _ 27. C. angustior. 



Spikes 3 to .j iu a small (6 to 10 mm. long), densely capitate, brownish-black head... .28. C illota. 



11. Deweyanae. 



Perigynia shallowly bidentate, 3..5 to 4 mm. long, the beak about '|; length of body 



29. C. leptopoda. 

 Perigynia deeply bidentate, 4 to 4.5 nun. long, the beak about V2 length of body 



30. C. bolanderL 

 12. Ovales. 



Sheaths green-striate opposite blades, except at mouth 31. C. feta. 



Sheaths white-hyaline opposite blades. 



Sheaths strongly prolonged upward at mouth opposite blade in a very membranaceous 



appendage; perigynia and scales greenish 32. C. fracta. 



Upper sheaths (at least) concave or truncate at mouth opposite blades. 

 Beak of perigynium flat and serrulate to usually strongly bidentate tip. 

 Perigynia 3.5 to 5 nun. long, 2 to 3 mm. wide. 



Perigynia thin with margins conspicuously wrinkled dorsally; culms 1 to 4 dm. 



high ; spikes ovoid, densely capitate 33. C. stramimformis. 



Perigynia thick with margins not wrinkled dorsally; culms 3 to 9 dm. high; spikes 



oblong in an oblong head 34. C. midticostata. 



Perigynia 3 to 3.5 nun. long, 1 to 1.5 mm. wide 35. C. »ubfusca. 



Beak of perigynium terete toward apex, the upper 1 to 3 imn. smooth or nearly so. 



Perigynia appressed, nearly or entirely covered by scales, the beaks not conspicuous 

 in the spikes. 



Culms slender; spikes in a flexuous nodding head 36. C. practicohi-. 



Culms stiff; spikes approximate in an erect head. 



Culms 1 to (i dm. high, the leaves not bunched near base; blades 2 to 3 nun. 



"wide, flat; beak of perigyaiium not hyaline at orifice !37. C tracyi. 



Cubns 1 to 3 dm. high, in large tufts, the leaves bunched near base; blades 

 1.5 to 2 mm. wide, more or less involute; perigynium beak hyaline at 

 orifice. 



Perigynia oblong-ovate, rather strotigly margined 38. C. pliaeoceplmla. 



Perigynia linear-lanceolate, very narrowly margined, boat-shaped 



39. C. lepurinella. 

 Upper part of perigynia conspicuous in the spike.s, not covered by scales. 



Perigynia lanceolate, 5.5 to 8.5 mm. iu length, 3 to 5 times as long as mde. 



Spikes about three, not capitate; scales little more than ^/i length of perigynia. 



40. C. daviji. 

 Spikes fi to 12, capitate; scales eriualing bodies of perigynia. ...41. C. spccifica. 



