216 Cyperaceae 



lA. Spike solitary and terminal. 

 2A. Style 2-fid; achenes lenticular; spikes dioecious or sometimes androgynous. 



3A. Leaves 1-1.5 mm. wide; perigynia distinctly longer than the scales, obliquely spreading when mature, with a rather long beak. 



2. C. \abanovii 



3B. Leaves 0.5-0.7 mm. wide; perigynia as long as the scales, short-beaked, horizontally spreading when mature 3. C. gynocrates 



2B. Style 3-fid; achenes triangular. 



4A. Scales of the pistillate flowers dark brown, lustrous; perigynia brownish or partially so; species of alpine regions. 



5A. Leaves narrow, rather rigid; culms obtusely angled, nearly smooth; perigynia reflexed at maturity 75. C. pyrenaica 



5B. Leaves flat, rather flaccid; culms sharply angled, scabrous; perigynia nearly erect at maturity 77. C. ha\kpdensis 



4B. Scales of the pistillate flowers pale to light yellowish brown or sometimes sanguineous. 

 6A. Scales of the pistillate flowers sanguineous; perigynia pubescent; species of woods. 



7A. Spikelets unisexual (plants dioecious); leaves about 1 mm. wide 125. C. grallatoria 



73. Spikelets androgynous; leaves 1—2.5 mm. wide 126. C. heteroclita 



6B. Scales of the pistillate flowers pale or light yellowish brown; perigynia glabrous. 

 8A. Perigynia thin-membranous, erect or spreading. 



9A. Spikes loosely flowered; perigynia 5-6 mm. long 155. C. rhizopoda 



9B. Spikes densely flowered; perigynia 1.5-4 mm. long. 



lOA. Spikes small, 3-6 mm. long, rather few-flowered; perigynia not inflated; achene compressed-trigonous. 



11 A. Leaves involute, less than 1 mm. wide; culms obtusely angled, almost smooth; perigynia 2 mm. long, oval, nerve- 

 less or nearly so 149. C. ha\onensis 



IIB. Leaves flat, 1.5-3 mm. wide; culms 3-angled, scabrous in the upper part; perigynia 2.5-3 mm. long, narrowly 



ovoid, finely nerved 150. C. onoei 



lOB. Spikes terete or ellipsoidal, 5-20 mm. long, rather many-flowered; perigynia somewhat inflated, loosely enclosing the 

 3-angled and not compressed achene. 

 12A. Culms densely scabrous on the angles; spikelets pale, 1 or 2 of the scales in lower part often rather elongate and 



somewhat bractlike 151. C. julta 



12B. Culms smooth or slightly scabrous only on the angles in upper part. 



13A. Culms sharply angled, smooth, flaccid; perigynia narrowly ovoid, 3—3.5 mm. long, gradually attenuate above 



into a rather long beak 152. C. uda 



13B. Culms somewhat obtusely angled; perigynia oval or ovoid, abruptly rather short beaked. 



14A. Spikes 1-2 cm. long; perigynia 1.5-1.8 mm. long 153. C. biwensis 



14B. Spikes 5-10 mm. long; perigynia 2.5-4 mm. long 154. C. capillacea 



8B. Perigynia subcoriaceous, reflexed when mature, 6-6.5 mm. long, narrowly lanceolate; sphagnum bogs 188. C. pauciflora 



IB. Spikes 2 to numerous. 



15A. Spikes usually bisexual, sessile, without prophylla at base; bracts not sheathing; style 2-fid, rarely 3-fid. 

 16A. Spikes androgynous, rarely unisexual and plants dioecious. 

 I7A. Style 2-fid; perigynia less than 7 mm. long. 

 18 A. Rhizomes long-creeping. 

 19A. Perigynia wingless. 

 20A. Perigynia planoconvex, crescent-shaped in transverse section, margins acute; along sandy coasts or in meadows. 



1 . C. arenicola 



20B. Perigynia biconvex, inflated, oblong in transverse section, margins obtuse; moist places 4. C. disperma 



19B. Perigynia narrowly winged. 

 21A. Perigynia slightly pubescent at least when young; pistillate scales yellowish brown or pale; forest species. 



5. C. pallida 

 21B. Perigynia glabrous; pistillate scales ferrugineous or reddish brown. 



22A. Stoloniferous; wet areas 6. C. pseudocuraica 



22B. Rhizomatous; grassy river banks 7. C. Uthophila 



18B. Rhizomes short; culms tufted. 

 23A. Perigynia membranous, with acute or winged margins, pale to pale brown on both sides. 



24A. Upper half of perigynia prominently winged; bracts foliaceous, elongate; meadows 8. C. neurocarpa 



24B. Perigynia not winged or narrowly winged from base to apex. 



25A. Perigynia many-nerved, with several tubercles scattered on the back 9. C. paxii 



25B. Perigynia smooth on back. 



26A. Longitudinal outer band of leaf-sheaths thinly membranous, transversely wrinkled, projected and longer than 

 the mouth of sheath at apex. 

 27A. Scales brownish ferrugineous; perigynia slightly scabrous on margins near the tip; culms slender, rigid; grassy 



places 10. C. laevissima 



27B. Scales pale or tawny; perigynia distinctly scabrous-margined; culms rather stout but soft; swampy areas. 



13. C. stipata 

 26B. Outer band of leaf-sheaths not wrinkled, with truncate apex not longer than the mouth of sheath; wet places 

 in mountainous regions. 



28A. Culms scabrous on the angles; perigynia lanceolate-ovate, gradually attenuate-beaked 11. C. albata 



28B. Culms glabrous; perigynia ovate or oval, rather short-beaked 12. C. nubigena var. franchetiana 



23B. Perigynia coriaceous, lustrous, dark chestnut brown, biconvex, with obtuse margins; swamps 14. C. diandra 



17B. Style 3-fid; perigynia nearly 10 mm. long; species of dune sands. 



29A. Culms obtusely angled, smooth or slightly scabrous on one angle; pistillate scales herbaceous, sulfur-colored, central portion 

 broad, many-nerved, the midrib projecting as a broad awnlike mucro; perigynia straight, longer than or as long as 

 the scales 15. C. hfibomugi 



