Dulichium arundinaceum

(Linnaeus) Britton

Bull. Torrey Bot. Club 21: 29. 1894.

Basionym: Cyperus arundinaceus Linneaus
Treatment appears in FNA Volume 23. Treatment on page 198. Mentioned on page 196.
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Rhizomes 2–5 mm thick; internodes 2–5 cm. Culms 2–14, erect, unbranched, jointed, aphyllopodic, 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.

Discussion

Varieties 2 (2 in the flora).

Selected References

None.

Key

1 Rhizomes 3–5 mm thick; culms 20–100 cm × 4 mm; leaf blades 3.5–8 mm wide; anthers 3–4 mm. Dulichium arundinaceum var. arundinaceum
1 Rhizomes 1–2 mm thick; culms 10–30(–40) cm × 1–2(–3) mm; leaf blades 1–3 mm wide; anthers (1.5–)1.8–2.6(–2.8) mm. Dulichium arundinaceum var. boreale