Phragmites australis (Cav.) Trin. ex Steud.
reed, phragmites
Robust perennials 1.5-3 m, with wide flat leaves borne along stout reed-like stems and with stout creeping rhizomes to 2 cm diam. Leaf-sheath rounded, chartaceous, glabrous, with numerous, minute cross-veinlets. Ligule c. 1 mm, truncate, short membranous, long ciliate. Collar brownish on both surfaces with dense, appressed, minute hairs, and ephemeral hairs to 6 mm on margin. Leaf-blade 40-60 × 1-3 cm, coriaceous, linear, somewhat narrowed at base, much-tapered above, smooth, but abaxially scabrid towards long, filiform, scabrid tip, margins scabrid above; disarticulating at ligule. Culm erect, rigid, usually simple, internodes glabrous. Panicle 20-30 cm, erect or finally drooping, purplish to brownish; branches numerous, glabrous except tufts of long (4 mm), silky hairs at nodes. Spikelets 10-14 mm, 3-6-flowered, finally widely gaping, lowest floret ♂ or Ø, others ⚥. Glumes unequal, persistent, 3-5-nerved, chartaceous, glabrous, ovate-lanceolate, acute; lower c. 4 mm, upper c. 6 mm. Lemma of basal floret 9-10 mm, 3-nerved, narrow-lanceolate, membranous, acute, persistent; lemmas of perfect florets shorter, narrower, tip long-acuminate to caudate. Palea 3-4 mm, « lemma, keels ciliate. Callus 0.5-1 mm, with dense long (6-8 mm) silky hairs. Rachilla c. 0.2 mm, glabrous, prolongation 0.5 mm, glabrous. Lodicules 0.3 mm, obovate, nerved, glabrous. Anthers 1.5-2 mm. Gynoecium: ovary 0.5 mm; stigma-styles 2 mm. Caryopsis not seen.
N.: several locations near Napier, in Hawkes Bay; S.: once in Westland. Stream margins, roadsides, waste places.
Naturalised from temperate zones in both Hemispheres.
In N.Z. mature megagametophytes are rare (Philipson and Connor 1984 op. cit.); seeds will rarely be found. Connor, H. E. et al. N.Z. J. Bot. 36: 465-469 (1998) reported 2 n = 4 x = 48 and 2 n = 8 x = 96 in some populations together with mixoploid numbers 2 n = 53, 54, and c. 264.
Generally known as P. communis Trin. until about 1975.
A variegated form is also grown as an ornamental grass and may escape into the wild.
