Scirpus americanus Pers.

  • Authority

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

  • Family

    Cyperaceae

  • Scientific Name

    Scirpus americanus Pers.

  • Description

    Species Description - Rhizomatous, colonial perennial 5–20 dm; stems avg stouter than in no. 6 [Scirpus pungens Vahl], often 1+ cm thick below, sharply triquetrous, with conspicuously concave sides, easily flattened in pressing; lvs few, all on the lower part of the stem, with normal sheath and short blade seldom over 1 dm long, sometimes 1 cm wide; spikelets 2–15, essentially sessile in a compact cluster, mostly 6–15 mm, subtended by a prominent, rather blunt, green bract 1–3.5(–5.5) cm that appears like a continuation of the culm, without additional bracts; scales thin, largely hyaline-scarious, the brown midrib firmer and commonly exserted as a short mucro about equaling the distal notch; bristles 4(–6), often unequal, retrorsely barbellate, not much if at all surpassing the achene; style bifid; achene planoconvex, 1.8–2.5 mm (including the 0.3 mm apiculus); 2n=78. Marshes, wet meadows, and other wet, low places, tolerant of alkali; N.S. to Wash., s. to S. Amer. Fr June–Sept. (S. olneyi; Schoenoplectus a.) The sterile hybrid with no. 6 is S. ×contortus (A. J. Eames) T. Koyama.

  • Common Names

    Olney-threesquare