690 CYPERACE.E. (SEDGE FAMILY.) 



*- 3. Panicece. Mostly stouter and narrow-leaved, with thinner spikes ; perigynium often 

 strongly nerved, not conspicuously triangular, often somewhat turgid ; bracts and 

 sheaths various. Sp. 75-78. 



+- 4. Bicolores. Small species with a beakless, more or less round or pyriform perigynium, 

 which is commonly glaucous ; terminal spike androgynous or all staminate ; stigmas 

 mostly 2. Sp. 79. 



- 5. Digitatce. Low species ; sheaths membranaceous or hyaline and colored, either not 

 prolonged into a bract or the bract very short and not foliaceous ; perigynium more or 

 less three-angled, often hairy, the beak straight or nearly so. Sp. 80 - 83. 



7. Sphaeridiophorae. Perigynium mostly short and rounded, three-angled in the Tri- 

 qwtrce, firm or hard in texture, not inflated, hairy or scabrous, the beak straight and 

 usually bifid ; staminate spike one ; pistillate spikes short (I/ long or less), usually glob- 

 ular or short-oblong, more or less sessile and approximate or the longer ones radical 

 (spike single in n. 84) ; bracts sheathless, short, or obsolete ; stigmas rarely two. Low 

 species of dry ground, with leaves all radical. 



- 1. Scirpince. Spike one, unisexual; plant dioecious. Sp. 84. 



- 2. Montana. Spikes two to several, the lowest occasionally long-peduncled and radical ; 

 perigynium rounded, contracted above and below, mostly bearing two prominent ribs, 

 more or less hairy. Low species of dry soils. Sp. 85-91. 



- 3. Triquetrw. Taller ; spikes mostly approximate at the top of the culm, oblong or cylin- 

 drical ; perigynium conspicuously 3-angled. Sp. 92. 



# 8. Phyllostachyae. Perigynium much as in the Montana; spike one, staminate above ; 



pistillate flowers few, often remote, usually on a more or less zigzag rhachis ; scales pro 

 longed and leaf-like. Sp. 93-95. 



* 9. Leptocephalsa. Perigynium thin in texture, green, oblong or lanceolate or linear in 



general outline, beakless ; spike one, staminate above, thin and slender ; stigmas mostly 

 three. Small, slender and grass-like. Sp. 96. 



* 10. Physocephalae. Spike one, globular or short-oblong, staminate at the apex ; peri- 



gynium straw-colored, paper-like, more or less inflated ; stigmas three. Leaves remark- 

 ably broad in our species. Sp. 97. 



2. VIGNEA. Staminate flowers few and inconspicuous, borne at the base or apex of the 

 pistillate spikes. Pistillate flowers in short sessile spikes (or spike single in some 

 cases), which are commonly more or less aggregated into heads or even panicled. Peri- 

 gynium plano-convex. Styles two and achene lenticular. The spikes, especially the 

 uppermost, usually have contracted bases when the staminate flowers are borne below 

 the pistillate ones, and empty scales at the top when the staminate flowers are borne 

 at the summit. 



* 11. Acroarrhenne. Staminate flowers borne at the top of the spikes (or, in the Multi- 



florce and Arenarice, spikes often wholly staminate and the plants occasionally dioecious). 

 * 1. Fcetidce. Spikes tawny or brown, not elongated, very densely aggregated into a con- 

 tinuous globose somewhat chaffy head ; perigynium ovate or ovate-lanceolate, nerveless 

 or nearly so, mostly thin in texture. Sp. 98, 99. 



- 2. Vulpince. Spikes mostly yellow or tawny when mature, densely aggregated or some- 



times somewhat scattered below or even panicled : perigynium thick in texture, spongy 

 at base, mostly stipitate, bearing very conspicuous nerves, which converge below and 

 are especially prominent on the outer side. Sp. 100-102. 



- 3. Multiflorce. Heads various, mostly loosely flowered, sometimes a panicle, yellow or 

 tawny; spikes short (rarely longer than broad), staminate flowers sometimes occupy- 

 ing whole spikes in the middle or at the apex of the head ; perigynium mostly small 

 and short and nearly nerveless, or in some species becoming nearly lanceolate and mor 

 or less prominently nerved, firm in texture, usually numerous. Sp. 103 - 108. 



- 4. Arenarice. Spikes longer than in the last section, linear or nearly so, aggregated into 



short, almost globose heads ; perigynium lanceolate or ovate-lanceolate, mostly larger 

 and more delicate in texture ; scales awn-pointed or very acute. Staminate flowej ? 

 variously situated. (C. arenaria.) 



