3. Fimbristylis thermalis Wats. 



Rhizomatous perennial, solitary or in small tufts, to about 1.5 m. tall; leaves 

 one third to one half the length of the scapes; blades linear, 1-4 mm. broad, flat 

 to somewhat involute, glabrous or with some pubescence toward the sheath and 

 apex on lower surface, upper surface just above ligule usually puberulent, veins 

 numerous and prominent on the lower surface, the pale marginal vein or veins 

 cartilaginous and ciliate-scabrid; sheath much broader, clasping, indurate, usually 

 with some pubescence, stramineous to dull-brown, with a broad and scarious 

 margin that is usually entire and converging to the blade at an acute angle; ligule 

 of short pale hairs present; spikelets oblong-cylindric to lance ovoid, 1-2 cm. 

 long, pale dull-brown, 1 to many in a closed to rather open paniculate system of 

 cymes; longest bract of the inflorescence shorter than the inflorescence; scapes 

 rather rigid, about the width of the leaves, glabrous, many-ridged, subterete below, 

 progressively flattened toward the inflorescence, the edges of the flattened portion 

 scabrous; fertile scales ovate, subentire, pale dull-brown, dorsally uniformly puberu- 

 lent, the midrib by contrast paler and exserted as a prominent cusp; stamens 3, 

 the anthers about 2 mm. long; style branches 2, the style flattened and fimbriate 

 from the base to above the point of branching; achene lenticular-obovoid, about 

 1.5 mm. long, dark lustrous-brown, finely reticulate, the individual foveae hori- 

 zontally rectangular and arranged in numerous vertical lines; joint of achene short, 

 persistent on fruit. 



On usually highly mineralized sandy substrate of marshes and about hot springs 

 in Ariz. (Coconino Co.); s. Calif., Nev., Ut. and Ariz., s. to B. Calif, and Coah. 



4. Fimbristylis caroliniana (Lam.) Fern. Fig. 208. 



Rhizomatous perennial, 1.5 (-2) m. tall; culrns solitary or in small tufts, the 

 bases rather shallowly set in the substrate; leaves subdistichous, usually spreading, 

 about half as long as the scapes; blades firm, linear, 2.5 (-7) mm. wide, the sur- 

 faces smooth or in some cases pubescent near the ligule or the upper face, the 

 backs with several raised nerves, the pale margin hyaline and scabrid; leaf-sheath 

 broader, clasping, firm, pale- to dark-brown, glabrous to sparsely pubescent, with 

 a wide stramineous to tan or reddish-brown scarious margin (this gradually or 

 abruptly passing into the blade and often ciliate at this point); ligule of appressed 

 hairs, usually complete; scapes about the width of the leaf blade, glabrous, many- 

 ribbed, subterete toward the base, usually flattened toward the apex (in which 

 case the edges scabrid); longest bract of the involucre much shorter than the in- 

 florescence to but slightly exceeding it, the back glabrous to puberulent, the margin 

 harsh; spikelets ellipsoidal to lance-ovoid or oblong, 5-15 mm. long, blunt to acute, 

 pale-dull-brown to reddish-brown, a few to many in a compound umbellate sys- 

 tem of cymes, the edges of the peduncles scabrid; fertile bracts ovate, glabrous or 

 puberulent on the backs toward the apex, the margin entire, the surface marked 

 by a thick usually paler area of midrib (this sometimes excurrent as a short 

 mucro); stamens 3, the apex of the flattened filaments narrowed, the anthers 

 about 3 mm. long; style 2-branched, flat, fimbriate from near the base to slightly 

 beyond the point of branching; achene lenticular-obovoid, about 1 mm. long, 

 pale- to deep-brown, often lustrous, finely reticulate with the reticule composed 

 of several fine rows of foveae or horizontally oriented rectangular cells; pedicel 

 joint very short, usually persistent. 



Brackish, alkaline or mildly acid sands or sandy peats of beaches, dune 

 swales, lake shores, roadside ditches, more rarely savannahs or flatwoods. Coastal 

 Plain from N.J. s. into the Fla. Keys and w. along the Gulf Coast to Tab.; Cuba. 



5. Fimbristylis tomentosa Vahl. 



Cespitose annual to 7.5 dm. tall; leaves from half as long to nearly the length 



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