Biorepository Data Portal

Plants annual, cespitose, 5-20(-30) cm, glabrous, plant base soft; rhizomes absent. Leaves distichous, shorter or longer than culms; sheaths keeled, entire or distally ciliate; ligule of short hairs complete; blades narrowly linear, 1-3 mm wide, flat, margin scabrid-ciliate. Inflorescence: anthelae compound, mostly diffuse, mostly turbinate, as broad as long, ascending-branching; scapes filiform to linear, distally variously compressed, sometimes alate, 0.5-1.5(-2) mm wide, edges scabrid; primary involucral bract usually 1, blade exceeding or exceeded by anthela. Spikelets red-brown or brown, mostly narrowly lanceoloid to narrowly ellipsoid, 3-7 mm; fertile scales lanceolate, keeled, 1.5-2 mm, narrowly acute, glabrous, midrib excurrent as mucro. Flowers: stamens (1-)2; styles 3-fid, slender, with 3 angled base, glabrous. Achenes pale brown, trigonous-obovoid, 0.5-0.7 mm, apiculate and 3-ribbed, smooth to variably warty. 2n = 10. Fruiting summer-fall, all year southward. Moist to wet sands, peats, silts, or clays, primarily of disturbed, sunny ground such as seeps, ditches, savanna, stream banks, reservoir drawdowns, and pond shores; 0-500(-1000) m; N.B., Ont., Que.; Ala., Ark., Conn., Del., D.C., Fla., Ga., Ill., Ind., Iowa, Kans, Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Nebr., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., S.Dak., Tenn., Tex., Vt., Va., W.Va., Wis.

Annual herb, tufted 5 - 20 cm tall Leaves: basal, more or less two-ranked, longer or shorter than culms, 1 - 4 mm wide, flat, narrowly linear, parallel-veined, with a sheathing base that encloses the stem. Sheaths shorter than the blade, broadly margined, keeled, and opening at the top. Inflorescence: a terminal, compound, dense or widely spreading anthela of spikelets subtended by a more or less upright bract (an anthela is a type of inflorescence which bears lateral branches that are longer than the main axis). Bract shorter than or surpassing the inflorescence. Flowers: minute, subtended by a floral scale, lacking sepals and petals. Stamens usually two, exserted. Pistil one. Style enlarged and three-angled basally, three-cleft. Fruit: a one-seeded achene, light brown, to 1 mm long, swollen, reverse egg-shaped and three-angled, obscurely three-ribbed, smooth to warty. Seed with a thin, non-adherent wall. Culm: 5 - 20 cm long, slender, flattened, solid, growing above the leaves. Spikelets: brown or reddish brown, 3 - 7 mm long, slender, narrowly lance-shaped to narrowly ellipsoid. Floral scales spirally arranged and overlapping, 1.5 - 2 mm long, narrowly egg-shaped with a thinly pointed apex, keeled, with a midrib that extends past the apex into a tiny point. Lower spikelet scales non-flowering, larger than the fertile flower scales, and often bladed.

Similar species: The similar Fimbristylis puberula differs by having two-cleft styles and biconvex achenes.

Flowering: July to late September

Habitat and ecology: Local in moist ground along shores and in ditches.

Occurence in the Chicago region: native

Etymology: Fimbristylis comes from fimbria, meaning "a fringe," and stylus, meaning style, referring to the hairy-fringed style in the genuine species. Autumnalis means "of the Autumn" or "flowering in the Autumn."

Author: The Morton Arboretum

Tufted annual to 2 dm; stems flattened, often harsh-edged; lvs subdistichous, to 4 mm wide; ligule a line of short hairs; longest invol bract suberect, sometimes surpassing the infl; spikelets 3-7 mm, slender, in a dense or open system of often subumbelliform cymes; scales lance-ovate, usually keeled, excurrently mucronate; stamens (1)2; anthers minute; style trifid, much longer than the achene, smooth; achene 1 mm, obovoid-trigonous, smooth to verrucose; 2n=10. Moist or wet, often disturbed sites; pantropical, n. to Me. and Minn

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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