CyPERACEAE 217 



29B. Culms acutely angled, scabrous on the angles; pistillate scales membranous, chestnut-brown, the central portion green, 

 3-nerved, die midrib excurrent as a necdlelikc, smooth awn; perigynia strongly divergent, usually longer than the scales. 



1 6. C. macrocephala 

 16B. Spikes gynecandrous. 



30A. Stigmas 3; achcnes moderately compressed; along roadsides or in fields 17. C. gibba 



30B. Stigmas 2. 



31A. Perigynia not white-puncticulate, gradually attenuate-beaked. 



32A. Perig)'nia reflexed when mature, with wingless but sharp margins; swamps. 



33A. Perigynia deltoid-ovate, slightly convex on back, scabrous on the margins near apex 18. C. echinata 



333. Perig>'nia lanceolate-ovate, strongly convex on back, nearly smooth on the margins 19. C. omiana 



32B. Perigynia erect at maturity, somewhat winged on the margins; wet meadows or forests. 



34A. Spikes densely aggregated in a terminal hemispherical head; annual or biennial herb with fibrous roots; perigynia 



narrowly lanceolate, long-stipitate, 7-10 mm. long 20. C. cyperoides 



3'IB. Spikes somewhat loosely disposed; perennials with short rhizomes; perigynia broadly lanceolate to broadly ovate, 

 sessile, 3-3.5 mm. long. 

 35A. Spikes loosely arranged; bracts conspicuous. 

 36A. Lower spikes with a very long leafy bract. 



37A. Perigynia oval, much compressed, with a rather broad beak 21. C. planata 



37B. Perigynia broadly lanceolate to ovate, with a very narrow beak. 



38A. Leaf-blades 2-4 mm. wide; spikelets 8-10, narrowly oblong, 8-15 mm. long; perigynia 4-4.5 mm. long. 



22. C. rochebrunii 

 38B. Leaf-blades 1-2 mm. wide; spikelets 4-7, ovoid-globose, 4-6 mm. long; perigynia about 3 mm. long. 



23. C. remotittscula 



36B. Lower 1 or 2 spikes widi a short setaceous bract 24. C. deweyana var. senanensis 



35B. Spikes approximate, usually without elongate bracts 25. C. maackji 



31B. Perigynia densely white-puncticulate, not winged on the margins, abruptly beaked or bcakless. 



39A. Pistillate scales chestnut-brown, reddish brown, or yellowish brown, or if pale, the perigynia distincdy beaked. 

 40A. Pistillate scales chesmut-brown to yellowish brown; perigynia usually smooth. 



41A. Pistillate scales chestnut-brown; perigynia at maturity longer than the scales; culms 20-30 cm. long; grassy slopes 



in alpine regions 26. C. lachenalii 



41B. Pistillate scales reddish brown to yellowish brown; swampy areas. 



42A. Culms 20-40 cm. long; leaves glaucous-green and minutely papillose; pistillate scales ovate-orbicular, ferrugineous 



or nearly so; perig)'nia grayish 27. C. macl^enziei 



42B. Culms (20-)40-80 cm. long, slender; pistillate scales brown, ovate; perigynia yellowish green or somewhat 

 brownish. 

 43A. Culms loosely tufted; leaf-blades 3-4 mm. wide, nearly smooth; perigynia elliptic, longer than scales, the 



scales brown, nearly obtuse 28. C. traiziscana 



43B. Culms densely tufted; leaf-blades 2.5-3 mm. wide, scabrous; perigynia ovate, more or less thickened, as long 



as or slightly shorter than the chestnut-brown scales 29. C. nemurensis 



40B. Pistillate scales pale or light yellow; perigynia slightly scabrous on the margins at apex; swamps or moist places in alpine 

 regions. 

 44A. Plants glaucous-green; leaf-blades 1.5-4 mm. wide; perigynia glaucous-green, becoming brownish at maturity. 



30. C. curta 

 44B. Plants bright green; leaves 1-2 mm. wide; perigynia light green at first, becoming brownish at maturity. 



31. C. bninnescens 

 39B. Pistillate scales pale; perigynia almost beakless, smooth; moist places. 



45A. Culms not slender; leaf -blades 1.5-3 mm. wide; perigynia 3.5-4 mm. long 32. C. pseudololiacea 



45B. Culms slender; leaves 1-2 mm. wide; perigynia 2.5-3.5 mm. long. 



46A. Leaves green, blades flat, 1-2 mm. wide; head 2-3 cm. long, the lower spikes distant; perigynia about twice as 



long as the scales, with elevated thick nerves 33. C. loliacea 



46B. Leaves glaucous-green, slightly folded, blades 1-1.5 mm. wide; head densely capitate, 5-8 mm. long, composed of 



2 or 3 closely approximate spikes; perigynia as long as the scales, with weak nerves 34. C. tenuiflora 



15B. Spikes bisexual or unisexual, peduncled or sometimes sessile with prophylla at base, bracts sheathing at base or not; style 3-fid, 

 rarely 2-fid. 

 47 A. Bracts not sheathing at base; style 2-cleft; achenes compressed. 

 48A. Perigynia smooth. 



49A. Stigmas extremely slender and long, persistent on the ripe achene; mountain streams 35. C. sadoensis 



49B. Stigmas distinctly shorter than the perig>'nia, falling ofl immediately after anthcsis. 



50A. Culms aphyllopodic (i.e., the outer sheaths of culm-base bladeless), the outer sheaths cinnamon-colored, membranous, not 

 keeled dorsally, nor ventrally reticulate; pistillate scales pale or light yellowish. 



51A. Culms 40-80 cm. long, stout; pistillate scales ovate, acute 36. C. shimidzensis 



51B. Culms 20-50 cm. long, slender; pistillate scales obovate, emarginate, short mucronate-tipped }>! . C. incisa 



SOB. Leaf -sheaths of culm-base somewhat reddish purple, more often brown and coriaceous, keeled dorsally, fibrously reticulate 

 ventrally. 

 52A. Rhizomes elongate. 



53A. Leaves with incurved margins. 



54 A. Leaves strongly flaccid; culms acutely angled; perigynia faintly nerved; swampy places and paddy fields. 



38. C. thunbergii 

 54B. Leaves slightly flaccid; culms obtusely angled; perigynia nerveless; costal swamps 39. C. subspathacca 



