188 CYPERACEAE 



capitate cluster of 3-8 spikelets : spikelets oblong-cylindric, obtuse, 4-8 mm. long, about 

 1 mm. thick, many-flowered : scales lanceolate, pale greenish brown, acuminate : stigmas 2 : 

 achenes obovoid, about 0.5 mm. long, biconvex, yellowish white, cancellate. 

 In moist soil. Msssouri to Texas, North Carolina and Florida. 



7. Finibristylis perpusilla Harper. Annual. Leaves few, basal, filiform, rather 

 shorter than the scapes : scapes in small prostrate radiating tufts, 1-3 cm. long : bracts of 

 the involucre few, mostly less than 1 cm. long : spikelets globular, 1-2 mm. in diameter, 

 sessile or nearly so during anthesis : scales green or yellowish, each tapering into a loosely 

 spreading awn : stamen 1 : stigmas 2 : achene oblong-cylindric, about 0.5 mm. long. 



In pine-land ponds, near Leslie, Georgia. Fall. 



8. Fimbristylis Frankii Steud. Annual, lower than the next following .species, the 

 leaves often shorter. Umbel mostly simple, the spikelets, or most of them, capitate and 

 sessile, ovoid or oval, blunt, the heads sometimes appearing almost sessile at the base : 

 achenes 0.5 mm. long, distinctly reticulated. 



In mud or wet sand, New Hampshire to Missouri, Tennessee and Louisiana. 



9. Fimbristylis autumnalis ( L. ) R. & S. Annual. Leaves glabrous ; blades nar- 

 rowly linear, flat, 1-2 mm. wide : scapes very slender, densely tufted, flat, 7-40 cm. long, 

 usually much exceeding the leaves : bracts of the involucre 2-3, usually all shorter than 

 the umbel : umbel compound or decompound, the primary rays 4-10 mm. long, the secon- 

 dary filiform : spikelets linear oblong, acute, 6-40 mm. long, 1 mm. thick or less : scales 

 ovate-lanceolate, subacute, strongly mucronate, greenish brown, the midvein prominent : 

 stigmas 3 : achenes obovoid, about 0.5 mm. long, nearly white, 3-angled with a ridge on 

 each angle, smooth or indistinctly reticulated, sometimes roughened. 



In moist soil, Maine to Michigan, Florida, Louisiana and Texas. Also in tropical America. 

 Summer and fall. 



10. Fimbristylis miliacea Vahl. Annual (always?), glabrous. Leaves rather tender ; 

 blades ensiform, long-attenuate : scapes weak, often loosely tufted, 1.5-6 dm. tall, mostly 

 overtopping the leaves, smooth : bracts of the involucre shorter than the inflorescence : 

 umbel erect, decompound, its peduncles often filiform : spikelets several or numerous, ovoid 

 or globular, 2-3 mm. long, blunt, pale brown : scales blunt, with broad midnerves : stig- 

 mas 3 : achenes 3-angled, obovoid, less than 1 mm. long, minutely roughened, pale. 



In bogs and ditches, Florida. Widely distributed in the tropics. Spring to fall. 



12. STENOPHYLLUS Raf. 

 Mostly annual herbs, with slender erect scapes. Leaves basal : blades narrowly linear 

 or filiform, the sheaths ciliate or pubescent. Spikelets umbellate, capitate or solitary, sub- 

 tended by an involucre of 1-several bracts, their scales spirally imbricated, mostly decidu- 

 ous. Flowers perfect. Perianth none. Stamens 2 or 3. Style glabrous, its base much 

 swollen and persistent as a tubercle of the achene as in Eleocharis. Stigmas 2-3. Achene 

 3-angled, turgid or lenticular. 



Spikelets in open umbels or sometimes solitary. 



Leaf-blades serrulate-eiliate : umbel not contracted : spikelets o-8-flowered. 



Umbel simple : scales of the spikelets obtuse : achene transversely wrinkled. 1. >?. capiUaris. 



Umbel compound : scales of the spikelets acute : achene minutely papillose. 2. .S. ciliatifolius. 

 Leaf-blades smooth and glabrous : umbel contracted : spikelets 10-15-flowered. 3. S. coarctatus. 

 Spikelets clustered in terminal heads. 



Bracts of the involucre with entire bases. 



Scales mucronate : involucral bracts few, short. 4. S. Floridanus. 



Scales subulate-tipped : bracts very long, much exceeding the heads. 5. S. Stenophyllus. 



Bracts of the involucre with fimbriate bases. 6. S. Ward. 



1. Stenophyllus capillaris ( L. ) Britton. Leaves roughish, much shorter than the 

 scape, their sheaths more or less pubescent with long hairs : scapes filiform, densely tufted, 

 erect, grooved, smooth, 5-25 cm. tall : involucral bracts 1-3, setaceous : spikelets narrowly 

 oblong, somewhat 4-sided, 5-8 mm. long, less than 2 mm. thick, several in a terminal um- 

 bel, or in depauperate forms solitary : scales oblong, obtuse or emarginate, puberulent, 

 dark brown with green keels : stigmas 3 : achenes yellow-brown, narrowed at the base, very 

 obtuse or truncate at the summit, nearly 1 mm. long, transversely wrinkled ; tubercle 

 minute, depressed. [^Isolepis capillaris (L. ) R. & S.] 



In dry or moist soil, throughout North America, except the extreme north. Also in!tropical Amer- 

 ica. Summer and fall. 



2. Stenophyllus ciliatifolius (Ell.) C. Mohr. Leaves erect ; blades bristle-like or 

 linear-filiform, channeled, serrulate-eiliate : scapes tufted, very slender, 10-30 cm. tall, 

 often slightly scabrous near the top : bracts of the involucre 2-3, similar to the leaves but 

 shorter, one about as long as the umbel, the others very short : spikelets numerous in a ter- 

 minal compound umbel, linear-oblong, 2-4 mm. long, acute, 6-r2-flowered : scales broad, 

 brown-margined, keeled, abruptly pointed, often ciliate toward the apex : achenes 3-angled, 



