7. FIMBRÍSTYLIS, Vahl. ([Pl. 3.])
Spikelets several–many-flowered, terete; scales all floriferous, regularly imbricated in several ranks. Perianth (bristles, etc.) none. Stamens 1–3. Style 2–3-cleft, often with a dilated or tumid base, which is deciduous (except in n. 4) from the apex of the naked lenticular or triangular achene. Otherwise as in Scirpus.—Culms leafy at base. Spikelets in our species umbelled, and the involucre 2–3-leaved. (Name compounded of fimbria, a fringe, and stylus, style, which is fringed with hairs in the genuine species.)
[*] Style 2-cleft, flattened and ciliate; achene lenticular; tubercle soon deciduous; spikelets many-flowered.
1. F. spadícea, Vahl, var. castànea, Gray. Culms (1–2½° high) tufted from a perennial root, rigid, as are the thread-form convolute-channelled leaves, smooth; spikelets ovate-oblong becoming cylindrical, dark chestnut-color (2´´ thick); stamens 2 or 3; achene very minutely striate and reticulated.—Salt marshes along the coast, N. Y. and N. J. to Fla. July–Sept.—Scales lighter colored than in the tropical form.
2. F. láxa, Vahl. (Pl. 3, fig. 1–5.) Culms slender (2–12´ high) from an annual root, weak, grooved and flattish; leaves linear, flat, ciliate-denticulate, glaucous, sometimes hairy; spikelets ovate, acute (3´´ long); stamen 1; achene conspicuously 6–8-ribbed on each side, and with finer cross-lines.—Low ground, Penn. to Fla., west to Ill. and La. July–Sept.
[*][*] Style 3-cleft and achene triangular; tubercle soon deciduous; spikelets smaller and fewer-flowered.
3. F. autumnàlis, Roem. & Schult. (Pl. 3, fig. 6–9.) Annual (3–16´ high), in tufts; culms flat, slender, diffuse or erect; leaves flat, acute; umbel compound; spikelets oblong, acute (1–2´´ long), single or 2–3 in a cluster; scales ovate-lanceolate, mucronate; stamens 1–3.—Low grounds, Maine to Fla., west to Ill. and La.
[*][*][*] Style 3-cleft, filiform and not ciliate; achene acutely triangular; tubercle more or less persistent.
4. F. capillàris, Gray. Low annual, densely tufted (3–9´ high); culm and leaves nearly capillary, the latter short; umbel compound or panicled; spikelets (2´´ long) ovoid-oblong; stamens 2; achene minutely wrinkled, very obtuse.—Sandy fields, N. Eng. to Fla., west to Minn., Tex., and the Pacific.
F. Váhlii, Link (F. congesta, Torr.), a diminutive southern species, with long filiform leaves, sessile capitate spikelets, narrow acuminate scales, and the style 2-cleft and not ciliate, has been found in ballast-sand along the northern coast.