Couch panicum

Panicum repens, the torpedograss or creeping panic grass, is a vigorous perennial grass of the family Poaceae growing 30-100 cm tall and probably native to the Mediterranean and Africa, now naturalised throughout the tropical and warm-temperate world as an aggressive weed of moist habitats. The plant spreads relentlessly by stout, hard, sharply-pointed, white scaly rhizomes that resemble torpedoes, from which arise erect to ascending culms that are stiff, smooth and sparsely branched. Leaf sheaths are glabrous or sparsely pubescent toward the margin and bear a ciliate-membranous ligule. Leaf blades are stiff, linear, flat or folded, 5-25 cm long and 2-8 mm wide, somewhat glaucous bluish-green and with finely scabrous margins. The inflorescence is an open, ovate to pyramidal terminal panicle 5-20 cm long with slender spreading branches that bear scattered short-pedicelled spikelets toward the tips. Each spikelet is narrow ovoid, 2-3 mm long, with two florets, the lower staminate or sterile and the upper bisexual with a smooth shining hardened lemma. It thrives in wet sandy soils along shorelines, ditches, irrigated rice paddies, dune slacks and disturbed wetlands, where it forms dense monospecific stands.