54 CYPERACEAE 



tt Spike solitary, sometimes dioecious. 

 Scales of the spikes elongated, leaf-like. 



XXX. PHYLLOSTACHYAE. 

 Scales of the spikes short, normal. 



XXXI. LEPTOCEPHALAE. 

 B. Staminate flowers few, at the summits or bases of the always sessile spikes, 

 or sometimes forming whole spikes, or variously intermixed with the pis- 

 tillate : stigmas always 2 : achene lenticular, compressed, ellipsoid or 

 plano-convex. VIGNEA. 

 Staminate flowers at the summit of the spike. 



Spike solitary, terminal. XXXII. DIOICAE. 



Spikes several, clustered. XXXIII. FOETIDAE. 



Spikes yellowish or brown at maturity, in compound or panicled clusters. 

 Perigynia strongly several-ner\^ed, especially on the outer face. 



XXXIV. VULPINAE. 

 Perigynia nerveless or faintly nerved. 



XXXV. MULTIFLORAE. 

 Spikes green or greenish when mature, aggregated or separated, in sim- 

 ple clusters. XXXVI. MUHLENBERGIANAE. 

 Staminate flowers at the base of the spike, variously intermingled with the 

 pistillate in the spikes, or occasionally forming whole spikes. 

 Perigynia wingless, the inner face flat. 



XXXVII. ELONGATAE. 

 Perigfynia with narrow or broad marginal wings, the inner face concave. 



XXXVIII. OVALES. 



I. PAUCIFLORAE. 

 A single species in our range. i. C. pauciflora. 



II. LUPUUNAE. 

 Pistillate spikes ovoid or globose, relatively few-flowered. 

 Perigynia subulate, reflexed when mature. 2. C. Collinsii. 



Perigynia conic or ovoid, not reflexed. 



Plants yellow or yellowish : perigynia little inflated. 

 Leaf-blades 2-4 mm. wide : staminate spike sessile. 



3. C. abacta. 

 Leaf-blades 4-12 mm. wide : staminate spike mostly peduncled. 



4. C. follictilata. 

 Plants green : perigynia well inflated. 



Leaf-blades 4-6 mm. wide : spikes loosely flowered. 



5. C. iulitniescens. 

 Leaf blades 6-10 mm. wide : spikes dense. 6. C. Asa-Grayi. 



Pistillate spikes oblong or cylindric, densely many-flowered. 

 Pistillate spikes oblong : achenes longer than thick. 



7. C. lupulitia. 

 Pistillate spikes cylindric : achenes not longer than thick. 



8. C. lupuliformis. 

 III. VESICARIAE. 



Spikes relatively small, 2.5 cm. long, or less, oblong to subglobose : stigmas 



often 2. 9. C. olig-osperma. 



Spikes relatively large, 2-15 cm. long, cylindric or oblong-cylindric : .'^tigmas 3. 

 a. Scales acute, acuminate, or smooth-awned, or the lower ones with slightly 

 roughened awns. 



