Phragmites australis

HABIT Perennial. Rhizomes elongated. Culms erect; reed-like; 150–600 cm long. Leaves cauline. Leaf-sheaths loose. Ligule a ciliate membrane. Leaf-blades deciduous at the ligule; 20–60 cm long; 8–32 mm wide. Leaf-blade surface smooth. Leaf-blade apex attenuate; filiform.

INFLORESCENCE Inflorescence a panicle; bearing juvenile spikelets at emergence.

Panicle open; oblong; dense; 20–50 cm long; 6–15 cm wide. Primary panicle branches profusely divided; bearing spikelets almost to the base.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels filiform.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 3–11 fertile florets; with diminished florets at the apex. Spikelets cuneate; laterally compressed; 12–18 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus elongated; 1–1.25 mm long; bearded; obtuse. Floret callus hairs 0.66 length of lemma.

GLUMES Glumes persistent; similar; shorter than spikelet; similar to fertile lemma in texture; gaping. Lower glume lanceolate; 3–4.5 mm long; 0.5–0.6 length of upper glume; membranous; without keels; 3–5 -veined. Lower glume apex acute. Upper glume lanceolate; 5–9 mm long; 0.5–0.7 length of adjacent fertile lemma; membranous; without keels; 3–5 -veined. Upper glume apex acute; muticous, or mucronate.

FLORETS Basal sterile florets male, or barren; with palea; persisting on inflorescence. Lemma of lower sterile floret similar to fertile lemma; lanceolate; 8–15 mm long; 1 length of fertile lemma; membranous; 3–7 -veined; acuminate. Fertile lemma lanceolate; 9–13 mm long; membranous; without keel; 1–3 -veined. Lemma apex acuminate. Palea 0.66 length of lemma; 2 -veined. Palea keels scaberulous. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2. Anthers 3 (2 in sterile floret). Ovary glabrous.

FRUIT Caryopsis with adherent pericarp. Hilum elliptic.

DISTRIBUTION Europe: northern, central, southwestern, southeastern, and eastern. Africa: north, Macaronesia, west tropical, west-central tropical, northeast tropical, east tropical, southern tropical, and south. Asia-temperate: Siberia, Soviet far east, Soviet Middle Asia, Caucasus, western Asia, Arabia, China, Mongolia, and eastern Asia. Asia-tropical: India and Indo-China. Australasia: Australia and New Zealand. Pacific: southwestern, south-central, and north-central. North America: Subarctic, western Canada, eastern Canada, northwest USA, north-central USA, northeast USA, southwest USA, south-central USA, southeast USA, and Mexico. South America: Mesoamericana, Caribbean, northern South America, western South America, Brazil, and southern South America.

NOTES Arundineae. FTEA.

Please cite this publication as detailed in How to Cite Version: 3rd February 2016.