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 in 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. 



1 8. 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. 



1 6. C. scoparia. 

 Perigynium ovate. 

 Beak bidentate. 



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



20. C. pratensts. 



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 an(J 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 s-nerved. 24. C. straminea. 



Perigynium 7-1 s-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. 



