Japan Flora: Scattered short-pubescent to nearly glabrous annual, 40-80 cm. high, with angled stems; leaves narrowly to sometimes broadly ovate, 3-8 cm. long, 1.5-4 cm. wide, obtuse with a small mucro at tip, cuneate at base, the petioles 1-8 cm. long, subtended by spreading spines about 1 cm. long; lower spikes axillary and globose, the upper elongate, the bracts narrowly lanceolate; perianth-segments 5, about 1.3 mm. long, nearly as long as the utricle, narrowly oblong, membranous, cuspidate; fruit imperfectly circumscissile; stigma rather long, about 1 mm. long, filiform. Aug.-Oct.

Honshu, Kyushu. Tropical America, now widely naturalized as a weed in the warmer regions of the world.