1.
Dulichium
arundinaceum
(Linnaeus) Britton, Bull. Torrey Bot. Club. 21: 29. 1894.
Cyperus arundinaceus Linneaus, Sp. Pl. 1: 44. 1753 (as arundinacea)
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.
Varieties 2 (2 in the flora): North America.
