226 



CYrERACEiE. 



Carex. 



23. 



25. 



Spike globose, straw-colored, of 5 to 20 spikelets : bracts expanded 

 at base, longer than the stem : perigyuiiim ovate-lanceo- 

 late, spongy at base. 21. C. athrostaciiya. 



Spike variegated, chestnut and green, subglobose, of 3 to 8 rather 

 large spikelets : perigyniuni broadly ovate or orbicular, 

 abruptly attenuate to a sharp minutely bidentate beak, 

 broadly winged to the base, exceeding the sualu. 22. C. stramixea. 



Spikelets distinct. 

 Spikelets male at top. 



Spike liuear-obloug, of 4 to 7 contiguous sessile spikelets : peri- 

 gyniuni obovate, attenuate to the base and to the obliquely 

 cut entire beak, nerveless, about as long as the broadly 

 ovate mucronate scale. 



Spikelets 2 to 6, remote, 2 - 6-flowered: perigynium oblong, bicon- 

 vex, abruptly miinitely beaked, closely striate-uerved, cori- 

 aceous, longer than the scale. 

 Spikelets male at bottom. 



Spikelets 3 to 10, ellipsoidal, remote : perigyniuni ovate, abruptly 

 short-beaked, many-nerved, si)oiigy at base. 



Spikelets 3 to 10 : perigyniuni lanceolate, acuminate, rostrate, 

 .spongy at base, exceeding the 1 - 3-nerved scale. 



Spikelets 4 to 8, polygamous : perigyniuni ovate from a cordate 

 sharp-margined base, nerved, sharply toothed, divergent, 

 equalling the .scale. 



Spikelets 3 or 4, round : perigynium ovate-lanceolate from a round 

 or ovate spongy base, rostrate, squarrose spreading, twice 

 as long as the scale. 



Spikelets pale, 8 to 10, ellipsoidal, 8 to 14 lines long: perigynium 

 lanceolate, acuminate, rostrate, twice as long as the scale. 



Spike fulvous, ovoid or oblong, of 8 to 12 crowded or contiguous 

 spikelets : perigynium narrowly lanceolate, attenuate, ros- 

 trate, longer than the scale. 



Spikelets numerous, pale, ellipsoidal, obovoid, crowded or con- 

 tiguous : perigynium elliptical, gradually beaked, longer 

 than the scale. 



Spike oblong, of 7 to 1 or more ellipsoidal contiguous spikelets : 

 perigyniuni ovate, winged to the base, exceeding the scale. 



Spike oblong, of 4 to 10 round or obovoid spikelets, the lower 

 subremote : perigyniuni ovate or oibicular, strongly nerved, 

 equalling the scale : nutlet orbicular, large. 33. C. adusta. 



* * * Uppermost spikelet male at base ; the rest female : stigmas 3. 

 Perigynium granular, obscurely nerved, the orifice entire or emargi- 



nate, shorter than the scale. 34. 



Perigynium not granular, nerved, bidentate : scales shorter. 35. 



Perigynium compressed above, triangular below, nerveless. 36. 



Perigynium nerveless, except 2 intramarginal nerves and 2 short 



nerves diverging from the base of the beak. 37. C. heteroneura. 



* * * * Spikelets unisexual ; the upper male, mostly single ; the rest 

 female or sparingly androgynous. 



Stigmas 2. 



Perigynium beakless, globose or pear-shaped, coriaceous, strongly 



nerved. 38. C. AUREA. 



Perigynium short-beaked. 



Very slender : spikelets rather loose : perigynium ovate, tapering 

 to an entire truncate orifice, not winged, obscurely nerved : 

 nutlet abruptly prolonged into the curved cylindrical style. 39. C. Kelloggii. 



Perigynium round-obovate or ovate, nerveless, abruptly beaked, 



orifice entire or emarginate : sheaths entire : stigmas 2 or 3. 40. C. vulgaris. 



Perigyniuni oval, rostellate with entire orifice, stipitate, papil- 



lo.se, strongly nerved, dec;iduous : nutlet globose. 41. C. decidua. 



Male .spikelet sometimes female below: perigynium elliptical, com- 

 pressed and empty above, with the beak entire, plano- 

 convex below, delicately nerved, resinously dotted, very 

 deciduous : sheaths fibrous-reticulate. 42. C. nudata. 



Male spikelets 1 to 4, the female 2 to 5 : ])erigynium elliptical or 

 obovate, stipitate, nerveless, resinously dotted, the orifice 



C. vallicola. 

 C. texella. 



C. caxescens. 



26. C. Deweyana. 



27. C. STERILIS. 



28. C. echixata, 



29. C. ARIDA. 



30. C. SCOPARIA. 



31. C. LAGOPODIOIDES. 



32. C. CRISTATA. 



C. BUXBAUMII. 

 C. BIFIDA. 

 C. ATRATA. 



