1922] Wiegand,—Carex laxiflora and its Relatives 193 
appearing blunt and rounded at apex; rhachis 
smooth: bracts often exceeding the culm..... 4. C. ormostachya. 
d. Angles of the culm smooth or obscurely erose- 
granulose; perigynia fusiform, very acute, scarcely 
beaked; rhachis usually granulose, bracts exceeding 
7" SSC EE URL Ee 6. C. ignota. 
c. Basal sheaths brown (angles of the culm smooth, 
serrulate or obscurely granulose). 
d. Spikes contiguous, the staminate more or less ob- 
scured; bracts much exceeding the culm, the 
latter more or less retrorsely scabrous. ...... 5. C. crebriflora. 
d. Spikes scattered, the staminate prominent; bracts 
shorter than or scarcely exceeding the apex of 
the staminate spike; culms with erose, obscurely 
erose-granulose, or even smooth angles. 
e. Perigynia slightly or not at all overlapping, 
strongly ascending, usually abruptly contracted 
into a slender beak-like point; bracts generally 
equalling or projecting beyond the staminate 
spike; rhachis of the alternate-flowered pistillate 
spikes smooth; angles of the culm smooth, very 
rarely slightly erose; leaves soft, on the basal 
Mu Wy broad.........-5 05 es 7. C. anceps. 
e. Perigynia more overlapping, more spreading, 
and more gradually acute, also averaging 
longer; bracts generally ending below the apex 
of the staminate spike; angles of the culm gen- 
eer minutely erose-granulose; basal leaves 
less broad. 
f. Pistillate spikes often loosely flowered, the 
larger on each plant 15-35 mm. long; rhachis 
smooth, sharply angled; scales abruptly 
cuspidate; perigynia ascending-spreading; 
staminate spikes stout, pale, with firm scales; 
lente eas MO... .. 6 os gg Ge 8. C. striatula. 
f. Pistillate spikes short and densely flowered, 
the larger 10-15 mm. long, in the variety 10— 
20 mm. long; rhachis narrower, not sharply 
angled; scales acute, not cuspidate; stamin- 
ate spike narrower, often brown, the scales 
less firm; leaves narrower, softer, deeper 
green, and often shorter. 
g. Pistillate spikes short and rather dense, 
the rhachis granulose. 
h. Perigynia spreading, curved outward, 
breadiy ellipsoidal...:.2:2 ge 9. C. styloflexa. 
h. Perigynia strongly ascending, lance- 
fusiform, nearly straight............... var. fusiformis. 
g. Pistillate spikes alternately flowered, the 
rhachis nearly or quite smooth .......... var. remotiflora. 
a. Perigynia obscurely 15-21-nerved, ellipsoidal, thin and 
ae walled, the tip rather slender and straight or 
slightly oblique, often abrupt; foliage deep green; bracts 
generally surpassing the staminate spike; culms re- 
trorsely scabrous, rarely almost smooth............ 10. C. leptonervia. 
1. C. ALBURSINA Sheldon, Bull. Torr. Bot. Club. xx. 284 (1893); 
Mackenzie in Britton & Brown's Ill. Fl. U. S. & Can. C. laxiflorat 
