Phragmites australis (Cav.) Trin. ex Steud.

Family: Poaceae, Tribe: Arundineae

Pertinent Synonyms & Notes (particularly those used in California; go to GRIN for other synonyms)

Phragmites communis Trin

Pertinent Common Names (particularly those used in California; go to GRIN for other common names)

common reed

Primary Disseminule Type


Description (diagnostics are in brown)

Spikelets solitary, pedicelled (pedicels filiform), consisting of 1 basal sterile floret, (2)3–10(11) fertile florets and similar-looking though diminished sterile florets at apex, cuneate, laterally compressed, 10–18 mm long. Disarticulation below each fertile floret.

Glumes persistent, similar, shorter than spikelet, gaping, lanceolate, membranous, without keel, 3–5-veined. Lower glume 3–4.5(7) mm long, 0.5–0.6 length of upper glume, apex acute. Upper glume 5–10 mm long, 0.5–0.7 length of adjacent fertile lemma, apex acute, mucronate.

Fertile florets: rachilla persistent, glabrous, callus elongated (1–1.25 mm long), obtuse, densely pubescent (hairs (4)6–8(10) mm long).

Fertile lemma lanceolate to linear, (6)8–15 mm long, membranous to hyaline, without keel, 1–3-veined, margins somewhat inrolled, surface glabrous, apex long-acuminate (but easily broken off).

Fertile palea (2)3–4 mm long, membranous to hyaline, 2-veined, keels scaberulous.

Caryopsis elliptic to oblanceolate, 1–3 mm long x ca. 0.5 mm wide, dark purplish-brown, styles persistent (but easily broken off), embryo 0.5 length of caryopsis, hilum oval, dark.

Risk Assessment (codes in yellow or red indicate cause for concern; assessments are current as of mid-2011; click AUQP, NZBORIC, or NZBPI for access to the most recent versions of these databases and possible assessment changes)