Polypogon interruptus Kunth

Family: Poaceae, Tribe: Aveneae

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


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

ditch polypogon

Primary Disseminule Type


Description (diagnostics are in brown)

Spikelets solitary, pedicelled (pedicel and/or stipe cuneate, 0.5–1 mm long), cuneate, laterally compressed, 2.5–3 mm long (not including awns), consisting of 1 fertile floret without rachilla extension. Disarticulation occurs below glumes with a small part of the pedicel/stipe attached.

Glumes subequal, oblong, 2–3 mm long, exceeding apex of florets, 2.5–3 length of adjacent fertile lemma, firmer than fertile lemma, gaping, membranous, keeled, 1-veined, surface scabrous, largest prickles extending up the keel beyond midlength, apices acute to truncate, unlobed to barely lobed, awn 1–3(5) mm long.

Floret: rachilla absent, callus glabrous.

Lemma oblong, 0.8–1.5 mm long, cartilaginous, ± transparent, glabrous, smooth and shiny, without keel, 5-veined, apex truncate and minutely dentate, 4-fid, awn 0.5–3.2 mm long.

Palea subequal to lemma, hyaline, 2-veined.

Caryopsis elliptic to oblanceolate, trigonous in cross-section, 0.8–1 mm long x 0.4–0.5 mm wide, light to medium brown, embryo <0.33 length of caryopsis, hilum linear.

Similar Species

Similar Species Comparison Chart

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)