CYPEEACEAE. 45 



Style-branches, or stigmas, 2 : achene lenticular. 



riants perennial : leaf-blades involute : stamens 2 or 3 : splkelets obtuse. 



1. F. puherula. 

 Plants annual : leaf-blades flat or nearly so : stamen 1 : 



splkelets acute. 2. F. Buldiviniana. 



Style-branches, or stigmas, 3 : achene 3-angled. 



Umbel simple or sparingly branched : splkelets stout, ovoid 



or oval, obtuse. 3. F. geminuta. 



Umbels much branched : splkelets narrow, often linear- 

 oblong, acute. 4. F. autumnalis. 



1. F. puberula (Michx.) Vahl. Plant thickened at the base. Leaves erect ; blades 

 involute, tlius often very slender, their sheaths green or purple-tinged, pubes- 

 cent : scapes slender, 3-6 dm. tall : bracts of the involucre mostly 2-4, minutely 

 pubescent, stiff: umbel with the central spikelet sessile: spikelets ovoid, 5-10 

 mm. long: scales thiunish, brown, with pale keel-like excurrent midribs, broad, 

 minutely pubescent : achenes obovoid, about 1 mm. long, cancellate, brownish. 



— S. Bare, in low grounds. — Schists. 



2. F. Baldwiniana Torr. Plant tufted. Leaves pale-green; blades flat, 1 mm. 

 wide: scapes slender, flattened, striate, 5—40 cm. long: spikelets ovoid or ovoid- 

 oblong, 6-12 mm. long: scales ovate, pale greenish-brown: stigmas 2: achenes 

 lenticular, obovoid, fully 1 mm. long, brown, longitudinally ribbed, the tubercled 

 ribs connected by fine cross-lines. — S. Eare, in moist soil. — Serpentine. 



3. F. geminata (Nees) Kunth. Plant lower than in the following species, leaves 

 often shorter : umbel mostly simple : spikelets, or most of them, capitate and 

 sessile, ovoid or oval, obtuse : achenes fully 0.5 mm. long, markedly reticulate. 



— Lower Susquehanna valley. In wet ground, on an island, near Peach Bottom. 



4. F. autumnalis (L.) E. & S. Plants 0.7-4 dm. tall. Leaves glabrous; blades 

 narrowly linear, flat, 1-2 mm. wide : scapes densely tufted, flat : spikelets linear- 

 oblong, acute, 6-40 mm. long: scales ovate-lanceolate, acutish. strongly mucro- 

 nate, greenish-brown : stigmas 3 : achenes obovoid, about 0.5 mm. long, nearly 

 white, smooth or indistinctly reticulate, the 3 angles ridged. — Eather common, 

 in moist soil. 



7. STENOPHYLLUS Eaf. Annual scapose herbs. Leaves basal: blades 

 narrowly linear or filiform, the sheaths ciliate or pubescent. Spikelets umbel- 

 late, capitate, or solitary, involucrate. Scales spirally imbricate, mostly decidu- 

 ous. Perianth wanting. Stamens 2 or 3. Style glabrous, the swollen base per- 

 sistent as a tubercle on the achene. Stigmas 2 or 3. Achene lenticular or 

 3-angled. 



1. S. capillaris (L.) Britton. Leaves shorter than the scape, their sheaths with 

 long hairs: scapes filiform, densely tufted, 5-40 cm. tall: involucral bracts 

 setaceous : spikelets narrowly oblong, 5-8 mm. long, several in a terminal umbel : 

 scales puberulent, dark-brown except the green keel: stigmas 3: achenes obovoid, 

 yellow-brown, rounded or truncate, nearly 1 mm. long, transverse-wrinkled; 

 tubercle depressed. — Common, in wet soil and on roadsides. — Sum. 



8. MABISCUS [Hall.] Zinn. Perennial herbs, similar to Bynchosporae 

 in habit. Spikelets oblong or ovoid, few-flowered, few together in clusters. 

 Scales imbricate, the lower empty, the middle ones mostly subtending imperfect 

 flowers, the upper one with a perfect flower. Perianth wanting. Stamens 2 or 

 sometimes 3. Style deciduous from the summit of the achene. Stigmas 2-3. 

 Achene ovoid to globose, smooth or longitudinally striate: tubercle wanting. 



1, M. mariscoides (Muhl.) Kimtze. Stems 3-9 dm. tall, stiff, smooth, obscurely 

 3-angled: leaves very narrow, with long compressed tips: umbels 2-4, com- 

 pound: sijikelets oblong, 5 mm. long, clustered on the stiff raylets: scales chest- 



