Plants 4-15 dm. Leaf blades linear to narrowly elliptic or linear-lanceolate, 5-10(-15) cm × (2-)5-10(-14) mm, lengths mostly 6-8 times widths, margins entire or minutely denticulate (revolute). Heads in open, inter-rupted, ± cylindric arrays (5-)8-20 cm (main axes visible between glomerules of heads). Involucres campanulate to cylindric, 4-5 mm. Pistillate florets 25-50. Functionally staminate florets 2-4(-5). Cypselae 1-1.4 mm.

Flowering Aug-Oct. Marshy areas, ditches, moist places in woods, in sand, sandy loam, and sandy clay; 0-20 m; La., Tex.; Mexico (Tamaulipas); West Indies; Central America; South America.