CYPERACEAE 187 
Style-branches or stigmas 2: achenes lenticular. 
Spikelets peduncled, forming umbels, or solitary and sessile. 
Perennial: leaf-blades strongly involute. 
Bracts of the involucre shorter than the spikelets. 1. F. schoenoides. 
Bracts of the involucre or some of them longer than the spikelets, 
Base of the style swollen. 
Seales coriaceous, shining. 2. F. spadicea. 
Seales.thinner, dull. 3. F. castanea. 
Base of the style not swollen. 4. F. Drummond. 
Annual: leaf-blades flat or nearly so. 5. F. laxa. 
Spikelets several, sessile, forming a terminal head. 
Scales acuminate: achenes obovoid. 6. F. Vahlii. 
4s 
- Scales subulate-tipped : achenes oblong-cylindric. F. perpusilla. 
Style-branches or stigmas 3: achenes 3-angled. 
Spikelets narrow, or if relatively thick, in simple'umbels. 
Umbel mostly simple: spikelets ovoid or oval, blunt: achenes distinctly 
reticulated. 8. F. Frankii. 
Umbel mostly compound : spikelets linear-oblong, acute: achenes smooth or 
indistinctly reticulated. 9. F. autumnalis. 
Spikelets globular or about as thick as long, in decompound umbels. 10. F. miliacea. 
1. Fimbristylis schoenoides Vahl. Perennial, glabrous. Leaves erect or nearly 
so : blades attenuate from the slightly dilated bsaes, involute : scapes more or less densely 
tufted, 1-4 dm. tall, mostly overtopping the leaves, smooth : bracts of the involucre shorter 
than the spikelets, inconspicuous : spikelets solitary, or 2 or 3 together forming an umbel, 
and the earliest one sessile, ovoid or conic-ovoid, 5-12 mm. long, 3-4 mm. thick, pale 
brown : scales rather blunt, firm : stigmas 2: achenes lenticular, broadly obovoid, barely 
1.6 mm. long, lustrous, whitish, not pointed. 
In low grounds, Florida. Also in tropical Asia. 
2. Fimbristylis spadicea (L.) Vahl. Perennial by a thickened base, glabrous. 
Leaves few: blades about 2 mm. wide when unrolled, their sheaths dark brown : scapes 
stiff, slender, 3-angled, wiry, tall, usually longer than the strongly involute, rigid leaves : 
bracts of the involucre 3-6, erect : umbel several-rayed, the rays nearly erect, 5-15 cm. 
long : central spikelets of the umbels and umbellets sessile, the others pedicelled : spikelets 
ovoid or ovoid-cylindric, acute, 5-12 mm. long, about 2 mm. in diameter: scales oval, 
obovate, or orbicular, obtuse or subacute, coriaceous, glabrous, shining, dark brown with 
green midribs: stigmas 2: achenes lenticular, obovoid, 1.5 mm. long, brown. 
xm marshes and shallow water, Virginia to Florida, near the coast. Widely distributed in tropical 
1Cca. 
3. Fimbristylis castànea (Michx.) Vahl. Perennial byathick base. Leaves few ; 
blades involute, less than 2 mm. wide, their sheaths green and more or less pubescent : 
scapes slender, 3-angled, 2-5 dm. tall, usually exceeding the leaves: bracts of the invo- 
lucre 2-4, short : umbel simple or compound, the rays 1-5 em. long: the central spike- 
lets sessile: spikelets oblong, 6-10 mm. long, 2-3 mm. in diameter: scales thin, brown 
with lighter midveins, broadly oblong or nearly orbicular, dull, puberulent, obtuse or 
mucronate: stigmas 2: achenes obovoid or oblong, about 1.5 mm. long, biconvex, pale 
brown, that of the prairie plant is shorter and less tapering to the base. 
On salt meadows, southern New York to Florida and Louisiana. Alsoin wet soil in the interior 
from Ontario, Michigan and Illinois to Kansas and Texas, and in tropical America.—A variety with 
copiously pubescent leaves and scapes, is F. castanea pubérula (Michx.) Britton. It ranges from Georgia 
and Florida to Texas. 
4. Fimbristylis Drummóndii (Torr. & Hook.) Britton. Perennial, glabrous. 
Leaves rather stiff; blades attenuate from the slightly dilated base, convex beneath, 
scarcely 2 mm. wide : scapes erect, somewhat tufted, about 9 dm. tall, twice as long as the 
leaves, smooth, deeply channeled on one side: bracts of the involucre 2-3, shorter than 
the inflorescence : umbel compound, with 4-6 curved rays 2-5 cm. long: spikelets oblong- 
ovate, about 12 mm. long, 3-5 mm. broad, pale brown, acute: scales mucronulate, rigid, 
slightly keeled near the apex : style not thickened at the base : stigmas 2: achenes lenticular, 
obovoid, about 1.5 mm. long, apiculate at the apex. [Isolepis Drummondii Torr. & Hook. ] 
In low grounds, Texas. 
5. Fimbristylis láxa Vahl. Annual, glabrous or sparingly ciliate. Leaves pale 
green; blades flat, about 1 mm. wide: scapes slender, flattened, striate, densely tufted, 
erect or ascending, 5-40 cm. long, usually longer than the leaves: bracts of the involucre 
3-5: umbel simple or slightly compound, the central spikelets sessile : spikelets ovoid or 
ovoid-oblong, 6-12 mm. long, about 2 mm. in diameter: scales ovate, thin, pale greenish 
brown, subacute or mucronulate : stigmas 2: achenes biconvex, obovoid, fully 1 mm. long, 
brown, longitudinally ribbed, the ribs tubercled and connected by very fine cross lines. 
In moist soil, southern Pennsylvania to Missouri, Florida and Texas. Also in tropical America. 
6. Fimbristylis Vahlii (Lam.) Link. Annual. Leaves setaceous or almost filiform, 
rough : scapes very slender, densely tufted, compressed, striate, 2-10 cm. high, longer than 
or equalling the leaves: bracts of the involucre 3-5, erect, much exceeding the simple 
