(Schult.) Torr., F. alamosa Fern. 



On a variety of moist sunny substrates such as savannahs, roadsides, grass- 

 lands and disturbed or cultivated areas, in mud on edge of ponds and streams, in 

 Okla. (Adair and Mayes cos.) and mostly s.e. Tex.; in temp, to trop. climates 

 of both hemispheres. 



8. Fhnbristylis Vahlii (Lam.) Link. Fig. 211. 



Cespitose low annual, the culms to 1.5 dm. tall (usually much lower); leaves 

 one third as long as the scape to equaling or exceeding it; blades linear-filiform, 

 spreading-recurved, less than 1 mm. broad, somewhat involute, the backs with 

 several prominent raised veins, often with small stiff ascending hairs, the margin 

 somewhat thickened and similarly hairy; leaf sheath broad, stramineous or pale- 

 brown, usually smooth or with a scattering of small hairs, the margin scarious, 

 entire, passing gradually into the blade; ligule absent; scapes stiffly ascending, 

 wiry, slightly broader than the leaves, glabrous, many-ribbed, subterete; spikelets 

 lance-ovoid to linear-ellipsoidal or oblong, 5-10 mm. long, usually acute, pale- 

 greenish-brown, 3 to 8 in a dense terminal cluster that are subtended by several 

 leaflike involucral bracts (these always exceeding the inflorescence and usually 

 at least the length of the basal leaves); fertile bracts ovate-lanceolate or oblong- 

 lanceolate, glabrous, stramineous or pale-green, the midrib conspicuous, dark- 

 green and pK>inted beyond the scale as a short erect or slightly recurved mucro; 

 stamen 1, the anther less than 0.5 mm. long; style 2-branched, much longer than 

 the achene, subterete, the base swollen, the surface smooth or papillate from about 

 the midpoint to the point of branching; achene obovoid, tumid, 0.5-0.7 mm. long, 

 pale, sometimes slightly iridescent, reticulate, the individual rectangular cells ar- 

 ranged horizontally in 5 to 7 vertical rows on a side. 



Fine sands, silts or clays, usually alluvial or shoreline situations, often on areas 

 of disturbed bottomland, in mud and wet sand on edge of ponds and lakes, in 

 Okla. (LeFlore, Pittsburg, Stephens, Mcintosh and McCurtain cos.), e. and s. 

 Tex. and Ariz. {Kearney & Peebles); S. C. s. to n. Fla., w. to Tex.; scattered lo- 

 calities in inland states; in w. U.S., Calif, and Ariz.; Mex. and C.A. 



9. Fimbristylis castanea (Michx.) Vahl. Fig. 208. 



Densely cespitose perennial to 1.5 (-2) m. tall, the bases of the plants castaneous, 

 deep-set in substratum, the outer leaves of a tuft and the older leaves persistent as 

 imbricated scales; leaves from one third the length of the culms to nearly as long; 

 blades usually very narrowly linear (rarely to 2 or 3 mm. broad), ascending, thick 

 (often semicircular in cross section), most frequently involute, smooth (particu- 

 larly toward the base), the nerves on the back numerous and indistinct but the 

 marginal nerve or nerves ciliate-scabrid with ascending stout-based hairs; sheathing 

 portion of the leaf broad (broadening gradually toward the base), pale-brown to 

 dark-brown or very deep-lustrous-reddish-brown, thick and rigid, the broad margin 

 thin or even scarious, entire except for the truncate or rounded ciliate apex; ligule 

 of hairs either absent or incomplete but a color change evident on the upper 

 surface of the leaf at the collar; scapes slender, wandlike, as wide as the blades 

 or somewhat wider, many-ribbed, terete toward the base of the plant, subterete to 

 oval or elliptical in cross section upwardly; longest bract of the involucre usually 

 shorter than the inflorescence or about the length of the inflorescence (rarely 

 longer), the blade somewhat flattened, ciliate-scabrid; spikelets usually ovoid or 

 lance-ovoid, very rarely cylindrical, 5-10 mm. long, rarely longer, the mature 

 ones usually pale- to dark-brown, dull, in a dense to open ascending or spreading 

 umbellate compound system of cymes; fertile bracts broadly ovate, smooth, brown, 

 usually dull, the margin entire or becoming arose with age, the apex rounded; 

 veins of the mid-portion of the scale obscure or visible as faint pale lines that 



411 



