48 



CYPEEACEAE. 



Perigynia plano-convex, yellowish : opaque 



part of leaf-sheath transversely rugulose. 



Perigynia thick, much rounded on outer 



surface, brownish : opaque part of leaf 



sheath not transversely rugulose. 



Perigynia 4-9 mm. long, spongy at base : beak 



exceeding the body. 



Spikes with staminate flowers at base, rarely en- 

 tirely staminate or pistillate. 

 Perigynia spongy at base, the body not wing- 

 margined. 



Perigynia not spongy at base, the body wing- 

 margined. 



B. Achenes triangular or lenticular ; if lenticular 

 the lateral spikes elongate and peduncled, and 

 terminal spike staminate. Eucarex. 

 Scales bract-like : achenes strongly constricted at 



the base. 



Scales not bract-like : achenes not strongly con- 

 stricted at the base. 



Spike solitary, the perigynia rounded and beak- 

 less at the apex. 

 Spikes one to many ; when one, the perigynia not 



as above. 



Perigynia triangular, membranous, closely en- 

 veloping the achene, nerveless, or 2-ribbed, 

 pubescent or puberulent, stipitate : bracts 

 sheathless or nearly so. 

 Perigynia obtusely triangular : foliage not 



pubescent. 



Perigynia acutely triangular : foliage pubes- 

 cent. 

 Perigynia not as above, or if so, bracts 



strongly sheathing. 



Lowest bract strongly sheathing : perigynia 

 beakless to beaked, entire, oblique or 

 emarginate at the apex ; or long-beaked 

 and apex hyaline, becoming bidentate, 

 teeth weak. 

 Bracts with obsolete or rudimentary 



blades. 

 Bracts with well-developed blades. 



Pistillate spikes short-oblong to linear, 

 erect, or if drooping the spikes 

 short and the perigynia acutely tri- 

 angular : terminal spike staminate. 

 Perigynia with few to many strong 



nerves, or nerveless. 

 Perigynia tapering at the base, tri- 

 angular, closely enveloping the 

 achene. 



Rootstock long-creeping. 

 Rootstock not long-creeping. 

 Perigynia rounded at the base, sub- 

 orbicular in cross-section, loosely 

 enveloping the achene. 

 Perigynia finely many-striate. 



Perigynia tapering at the base, 



constricted at the apex, obtusely 



triangular, closely enveloping 



achene. 



Perigynia rounded at both ends, in 



cross-section suborbicular. 

 Pistillate spikes elongate-linear to cylin- 

 dric, slender-peduncled, the lower 

 ones drooping. 



Perigynia beakless or short-beaked. 

 Perigynia conspicuously or strongly 



beaked. 



Lowest bract sheathless, or if sheathing, 

 perigynia with strongly bidentate non- 

 hyaline apex, and stiff teeth. 

 Perigynia or foliage (at least lower 

 sheaths) pubescent; perigynia beakless, 

 or beak not strongly bidentate. 



II. MULTIFLORAE. 



III. PANICULATAE. 



IV. STENOBHYNCHAE. 



V. ELONGATAE. 

 VI. OVALES. 



VII. PHYLLOSTACHYAE. 



VIII. POLYTRICHOIDEAB. 



IX. MONTANAE. 



X. TRIQUETRAE. 



XI. PEDDNCULATAE. 



XII. PANICEAE. 

 XIII. LAXIFLORAE. 



XIV. GRANULARES. 



XV. OLIGOCARPAE. 

 XVI. GRISEAE. 



XVII. GRACILLIMAE. 

 XVIII. DEBILES. 



XIX. VlRESCENTES. 



