64 CYPERACEAE. 



erect, lanceolate to ovate, more or less winged, very seldom wingless, taper- 

 ing into a long serrulate or ciliate beak, with the orifice oblique or bidentate. 



Perigynium winged. 



Spikes ih an oval or roundish head ; perigynium ovate to lanceolate ; beak slit 

 on the convex side. 

 Bracts longer than the inflorescence. 17. C. athrostachya. 



Bracts inconspicuous. 



Perigynium broadly ovate to suborbicular, rather light brown or greenish. 



18. C. f estiva. 

 Perigynium lanceolate, very dark brown and shining. i8a. C. ebenea. 

 Spikes in a more or less distinct spike. 



Perigynium lanceolate, narrowly winged, ciliate; inflorescence short. 



16. C. scoparia. 

 Perigynium ovate. 

 Beak bidentate. 



Perigynium thin, green ; spikes nodding when young, tapering at the base. 



20. C. pratensis. 

 Perigynium firm, brown ; spikes erect, strict. 22. C. Liddonii. 



Beak not bidentate. 



Beak slit on the convex side. 19. C petasata. 



Beak oblique at the orifice. 21. C. siccata. 



Perigynium not winged. 23. C. Bonplandii. 



9. Pterocarpae. 



Spikes several, large and heavy, dense-flowered, contiguous or the lower 

 ones remote, sessile, gynaecandrous ; bracts inconspicuous; scales light-brown 

 to green; perigynium erect, ovate to almost orbicular, much compressed, 

 nerved, broadly winged, prominently serrulate, the beak bidentate. 



Spikes ovate in a roundish head. 25. C. straminiformis. 

 Spikes in a spicate inflorescence. 



Perigynium about 5-nerved. 24. C. straminea. 



Perigynium 7-15-nerved. 26. C. festucacea. 



10. Cephalostachyae. 



Spikes several, reddish brown, androgynous, dense-flowered, sessile in a 

 roundish or ovoid head; bracts inconspicuous; scales ovate, acute; peri- 

 gynium stipitate, erect, ovate, turgid, spongious, prominently many-nerved, 

 shining reddish-brown, the beak scabrous, obliquely cut, with hyaline orifice. 



One species. 27. C. stenophylla. 



11. Sphaerostachyae. 



Spikes several, androgynous, dense-flowered, sessile in a roundish head; 

 bracts inconspicuous; scales broadly ovate with hyaline margins; perigynium 

 spreading at maturity, stipitate, ovate, turgid, nerveless or nearly so, yellow- 

 ish, becoming fuscous at maturity, scabrous along the prominent, obliquely 

 cut beak. 



One species. 28. C. incurva. 



