T: [USA, Massachusetts] Lewis Bay, West Yarmouth, 14 Oct 1914, M.L.Fernald & F.K.Butters 15064; holo: GH; iso: GH, NEBC [and Pl. Exs. Gray. 183, incl. GH, LD, WU].
Perennials, 70–100 cm tall, clonal; rhizome stout, creeping, branched, 3–7 mm in diam. with internodes c. 0.5–2 cm long; sterile shoots present. Stem terete, 2–4 mm in diam.; sterile shoots resembling a single leaf, with cataphylls. Cataphylls 2–3, tight, to c. 10 cm long; blade reduced or filiform. Cauline leaf single, terete, 25–35 cm long, 1–2 mm in diam., pluritubular, imperfectly septate; auricles obtuse, 0.5–1.5 mm long, scarious. Lower bract leaf–like, shorter than inflorescence. Inflorescence decompound, anthelate, c. 5–10 × 3–5 cm, with patent lower main branches, of 25–60 ±globose c. 15–50-flowered heads. Tepals ±equal or outer ones slightly longer, lanceolate to oblong-ovate, 2.0–2.5 mm long, obtuse, greenish becoming pale brownish; margins ±narrow, scarious. Stamens 6; anthers c. 0.8–1.0 mm long; filaments c. 0.5 mm long; style c. 1 mm long; stigmas c. 2 mm long. Capsule trilocular, ovoid-trigonous, ±acute, narrowing in c. 0.5 mm rostrum, c. 2.5 mm long, slightly exceeding perianth. Seeds few, c. 0.5 mm long; appendages absent.