Dulichium arundinaceum (L.) Britton
Family: Cyperaceae
Three-Way Sedge,  more...
Dulichium arundinaceum image
Paul Rothrock  
Rhizomes 2-5 mm thick; internodes 2-5 cm. Culms 2-14, erect, unbranched, jointed, aphyllo-podic, terete, 20-100 cm × 2-5 mm; internodes hollow. Leaves: sheaths 2-14, bladeless, green, often with white dots in intervenal areas, with brown-hyaline 1-2 mm margin at mouth, firm; blades 3-15 per culm, 3-ranked, ascending, thick, 4-15 cm × 1-8 mm, ± leathery, glabrous; distal 5-20 leaves serving as bracts. Inflorescences 6-30 cm; spikes 1-17, in sheath axils, 2-5 cm. Spikelets 2-ranked, appressed-ascending to ascending-spreading, linear-lanceolate, flat, 1.5-3 cm × 1.2-2.5 mm; rachilla winged, wings hyaline, usually containing spongy tissue proximally, occasionally ciliate; scales decurrent, spongy-based, 5-9.5 × 1.4-2.4 mm, each subtending flower. Flowers 2-ranked, sessile; scales green with gold-hyaline margins; perianth bristles 6-9, 4-7.5 mm, stiff; stamens 3, longer than perianth bristles; pistils 1, 2-carpellate; styles 1, 3.8-6 mm, base persistent on achene; stigmas 2, 1-3.8 mm. Achene stipitate, 2-4 × 0.8-1.1 mm (excluding style base), shorter than perianth bristles.
Perennial herb with rhizomes 20 cm - 1 m tall Inflorescence: consisting of short-stalked, axillary spikes, 6 - 30 cm long, subtended by leaf-like bracts. Spikes one to seventeen, in axils of sheaths, 1 - 5 cm long, consisting of three to ten spikelets. Flowers: two-ranked, stalkless, minute, subtended by a floral scale, lacking sepals and petals, with six to nine bristles. Bristles stiff, 4 - 7.5 mm long, slightly longer than achene. Stamens three, exserted. Pistil one. Style one, two-cleft. Stigmas two, 1 - 4 mm long. Fruit: a one-seeded achene, short-stalked, 2 - 4 mm long, about 1 mm wide, biconvex, beaked with the persistent style. Seed with a thin, non-adherent wall. Spikelets: two-ranked, 1 - 3 cm long, 1 - 2.5 mm wide, flat, narrowly lance-shaped, with a winged axis. Scales four to eight, spirally arranged and overlapping, pointed, 5 - 9.5 mm long, 1.5 - 2.5 mm wide, ribbed. Lower leaves: consisting of bladeless sheaths, two to fourteen, firm, green, white-dotted, with a 1 - 2 mm wide margin at the mouth. Upper leaves: three to fifteen per culm, three-ranked, alternate, ascending, thick, 4 - 15 cm long, 1 - 8 mm wide, flat, linear, parallel-veined, with a sheathing base that encloses the stem. The uppermost five to twenty leaves reduced to bracts. Culms: two to fourteen, upright, unbranched, 20 cm - 1 m long, 2 - 5 mm wide, circular in cross-section, jointed, internodes hollow.

Similar species: No information at this time.

Flowering: July to late August

Habitat and ecology: Bogs and marshes.

Occurence in the Chicago region: native

Etymology: The origin of Dulichium is unknown. Arundinaceum means reed-like.

Author: The Morton Arboretum

Erect, 3-10 dm; lvs numerous, the lower bladeless, the upper sheaths often overlapping; blades mostly 5-15 cm נ2.5-8 mm; peduncles scarcely exserted; spikes 1-3 cm; spikelets 10-25 mm; scales 5-8 mm, narrow, acuminate, several-nerved; achene short- stipitate, 2.5-3 mm, beaked with the long, slender, persistent style; 2n=32. Swamps and marshes; Nf. to Minn., s. to Fla. and Tex.; B.C. to Calif. and Mont.

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

©The New York Botanical Garden. All rights reserved. Used by permission.
Dulichium arundinaceum image
Paul Rothrock  
Dulichium arundinaceum image
Paul Rothrock  
Dulichium arundinaceum image
Morton Arboretum  
Dulichium arundinaceum image
Morton Arboretum  
Dulichium arundinaceum image
Dulichium arundinaceum image
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