Phalaris

1. Glumes mostly (3.5–) 4–5.7 mm long, the keel not winged; sterile lemmas very hairy, ca. 0.5–2 (–3) mm long; rhizomatous perennial, with elongate lobed panicle (or the lower branches spreading at anthesis).

P. arundinacea

1. Glumes mostly 6–8 mm long, the keel prominently winged; sterile lemmas glabrous or nearly so, ca. 2.5–3.7 mm long; annual, with very dense, compact, ovoid panicle.

P. canariensis