174 FLORA. 



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 a 

 green midvein; stamens 2; style 2-cleft; achene lenticular, obovate, brown. In 

 marshes and shallow water, Va. to Fla., near the coast. Widely distributer! 

 in tropical America. July-Sept. 



2. Fimbristylis castanea (Michx.) Vahl. MARSH FIMBRISTYLIS. (i. F. f. 

 605.) Perennial by a thick base; culms slender, 3-angled, 0.2-0.5 m - * a ^' usualN- 

 exceeding the leaves. Leaves involute, less than 2 mm. wide, their sheatns green 

 and more or less pubescent; leaves of the involucre 2-4, short; umbel simple or 

 compound, the rays 1-5 cm. long; central spikelets sessile; spikelets oblong, 6-10 

 mm. long, 2-3 mm. in diameter; scales thin, brown with a lighter midvein, 

 broadly oblong or nearly orbicular, dull, puberulent, obtuse or mucronate; stamens 

 2-3; style 2-cleft; achene obovate or oblong, biconvex, pale brown. On salt 

 meadows, southern N. Y. to Fla. and La. Also in wet soil in the interior from 

 Ont., Mich, and 111. to Kans. and Tex., and in tropical America. The achene in 

 the prairie plant is shorter and less tapering to the base than in the coast form. 

 July-Sept. 



3. Fimbristylis laxa Vahl. WEAK FIMBRISTYLIS. (I. F. f. 606.) Annual; 

 roots fibrous ; culms slender, flattened, striate, densely tufted, erect or ascending, 

 5-40 cm. long, usually longer than the leaves. Leaves flat, about I mm. wide, 

 glabrous or sparingly ciliate, pale green, those of the involucre 3-5 ; umbel simple 

 or slightly compound, the central spikelet sessile ; spikelets ovoid or ovoid-oblong, 

 6-12 mm. long, about 2 mm. in diameter ; scales ovate, thin, pale greenish brown, 

 subacute or mucronulate ; stamen I ; style 2-cleft, pubescent ; achene biconvex, 

 obovoid, light brown, longitudinally ribbed, the ribs tubercled and connected by 

 very fine cross-lines. In moist soil, S. Penn. to Fla., west to 111., Mo. and Tex. 

 Also in trop. Am. July-Sept. 



4. Fimbristylis Vahlii (Lam.) Link. VAHL'S FIMBRISTYLIS. (I. F. f. 607.) 

 Annual ; culms very slender, densely tufted, compressed, striate, 2-10 cm. high, 

 longer than or equalling the leaves. Leaves setaceous or almost filiform, rough, 

 those of the involucre 3-5, erect, much exceeding the simple capitate cluster of 3-8 

 spikelets ; spikelets oblong-cylindric, obtuse, 4-8 mm. long, about I mm. thick, 

 many-flowered; scales lanceolate, pale greenish-brown, acuminate; stamen I; style 

 2-cleft, glabrous below; achene minute, biconvex, yellowish-white, cancellate. In 

 moist soil, Mo. to Tex., east to N. Car. and Fla. July-Oct. 



5. Fimbristylis autumnalis (L.) R. & S. SLENDER FIMBRISTYLIS. (I. F. f. 

 608.) Annual ; roots fibrous ; culms very slender, densely tufted, flat, 7-40 cm. 

 long, usually much exceeding the leaves. Leaves narrowly linear, flat, 1-2 mm. 

 wide, glabrous, those of the involucre 2-3, usually all shorter than the umbel ; 

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

 filiform; spikelets linear-oblong, acute, 6-40 mm. long, I mm. thick or less; scales 

 ovate-lanceolate, subacute, strongly mucronate, greenish-brown, the midvein prom- 

 inent; stamens 1-3; style 3 - cleft ; achene obovoid, nearly white, 3-angled with a 

 ridge on each angle, smooth or indistinctly reticulated, sometimes roughened. In 

 moist soil, Me. to Mich., south to Fla. and La. Also in trop. Am. Depauperate 

 forms occur with culms not over 2 cm. high bearing solitary spikelets. June-Sept. 



6. Fimbristylis Frankii Steud. Annual, lower than the preceding 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 ses- 

 sile at the base; achenes rather larger, distinctly reticulated. In mud or wet sand, 

 N. II. to Mo., Tenu. and La. June-Sept. 



9. SCI'RPUS L. (See Appendix.) 



Annual or perennial very small or very large sedges, with leafy culms or the 

 leaves reduced to basal sheaths. Spikelets terete or somewhat flattened, solitary, 

 capitate, spicate or umbellate, subtended by a i-several-leaved involucre or the in- 

 volucre wanting in some species. Scales spirally imbricated all around, usually 

 all fertile, the 1-3 lower sometimes empty. Flowers perfect. Perianth of 1-6, 

 slender or rigid, short or elongated, barbed, pubescent or smooth bristles, or none 

 in some species. Stamens 2-3. Style 2-^-ckft, not swollen at the base, wholly 



