Classification
 Nomenclature
Scientific Name:
Elytrigia repens (L.) Nevski, Trudy Botanicheskogo Instituta Akademii Nauk SSSR. Series 1. Flora i Sistematika Vyssikh Rastenii. Acta Instituti Botanici Academiae Scientiarum URPSS 1: 14 (1933)
Synonymy:
  • Triticum repens L., Sp. Pl. 86 (1753)
  • Elymus repens (L.) Gould
  • Agropyron repens (L.) P.Beauv.
Vernacular Name(s):
Couch; English couch; Herewhenua; Twitch
 Description

Perennial, 30–150–(200) cm, forming dull green, sometimes bluish green tufts from long-creeping rhizomes. Leaf-sheath glabrous or with ± scattered fine hairs, firmly membranous, light brown to light green. Auricles to 2 mm very fine, membranous. Ligule rim-like, 0.25–0.5 mm, scarious at tip. Leaf-blade 15–40 cm × (2)–3–10 mm, flat, soft to rather stiff, abaxially smooth or sparsely scabrid above, adaxially with slender inconspicuous ribs, usually sparsely long hairy, or glabrous, linear, ± abruptly narrowed to acute tip, margins white, prickle-toothed. Culm 20–150 cm, erect or geniculate below, internodes glabrous. Spike (5)–10–30 × 0.5–1.5 cm, erect, spikelets very close-set or sometimes more distant below; rachis scabrid on margins, otherwise smooth or sometimes abundantly softly hairy. Spikelets 10–20 mm, green or sometimes bluish green, oblong-elliptic or wedge-shaped, 3–8-flowered. Glumes ± equal, 7–12 mm, 5–7-nerved, lanceolate, obtuse or acute, coriaceous, scabrid on midnerve near tip, adaxially with many small white hairs. Lemma 8–13 mm, 5-nerved, coriaceous, rounded to ± keeled above, abaxially glabrous, adaxially clothed in small white hairs, awnless, mucronate or awned to 8 mm. Palea ≤ lemma, keels scabrid, apex entire, ciliate, flank margins wide, membranous ± contiguous, interkeel glabrous, adaxially clothed in short white hairs. Callus 0.2–0.3 mm, shortly bearded. Rachilla to 1.25 mm, shortly hairy. Lodicules to 1.6 mm, shortly ciliate, > ovary. Anthers 3.5–6 mm. Gynoecium: ovary 0.5–0.7 mm; stigma-styles 2.5–3.0 mm. Caryopsis 3.5–5.5 mm; embryo 1–1.25 mm; hilum = caryopsis.

[From: Edgar and Connor (2000) Flora of New Zealand. Volume 5 (second printing).]

 Biostatus
Exotic
 Bibliography
Linnaeus, C. 1753: Species Plantarum. Impensis Laurentii Salvii, Stockholm.
Trudy Botanicheskogo Instituta Akademii Nauk SSSR. Series 1. Flora i Sistematika Vyssikh Rastenii. Acta Instituti Botanici Academiae Scientiarum URPSS