[Phalaris bulbosa Cav., more, Phalaris bulbosa var. coerulescens (Desf.) Knoche, Phalaris coerulescens var. concolor Lojac., Phalaris coerulescens var. maior De Not., Phalaris coerulescens var. ovata Parl., Phalaris coerulescens var. tenuis Asch. & Graebn., Phalaris coerulescens var. villosula De Not. ex Parl., Phalaris paradoxa var. coerulescens (Desf.) Paunero, Phalaris variegata Spreng.]
Plants perennial; cespitose, not rhizomatous. Culms 70-200 cm, swollen at the base. Ligules 4-6 mm, rounded to narrowly acute; blades 4-20(25) cm long, 1-5(7) mm wide. Panicles 3-12 cm long, 1-2.3 cm wide, ovoid to cylindrical; branches with groups of 4-7 staminate (rarely sterile) spikelets clustered around a terminal pistillate or bisexual spikelet, the spikelets homomorphic; pedicels glabrous or sparsely hispid; disarticulation below individual bisexual spikelets or below the spikelet clusters. Spikelets heterogamous, some staminate or sterile, others bisexual or pistillate; florets 1-3, if more than 1, the lower florets sterile and highly reduced, the terminal (or only) floret staminate, pistillate, or bisexual. Glumes usually 5-9 mm long, 1.1-2 mm wide, glabrous or hirsute, keels winged, wings 0.2-0.5 mm wide, entire or irregularly dentate distally, lateral veins conspicuous, scabrous, apices mucronate, mucros 0.3-0.7(1) mm, glumes of the spikelets near the base of the panicle to 3 mm; sterile florets of all spikelets absent or to 1/10 as long the terminal florets, glabrous or almost so; terminal florets of all spikelets homomorphic, staminate, pistillate or bisexual, about 2.5 mm long, 0.7-1.4 mm wide, glabrous or with a few short hairs at the base; anthers 2.5-3 mm. Caryopses 2.8-3.3 mm long, 1.2-1.4 mm wide. 2n = 14, 42.
Phalaris coerulescens is native around the Mediterranean; it is now established in northern Europe and South America. It was found in Contra Costa County, California, in 2000.