Stems clustered, slender, erect, 2-5 dm, with usually 2-4 terete, septate lvs; infl decompound, very diffusely branched, widely spreading, 1-2 dm, usually constituting a third of the height of the plant, bearing very many obpyramidal, 3-10-fld heads; fls eprophyllate; tep subequal, linear-subulate, 2.3-2.8 mm; stamens 3; fr unilocular, golden-brown, prismatically linear-trigonous or subtriquetrous, 4-6 mm, a fifth as thick, gradually attenuate, very acute, much surpassing the tep. Wet soil and muddy shores; s. Ind. to Mo. and Okla., s. to Ala. and Tex.; coastal plain from se. Va. to S.C.; reported from W.Va.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Common in southern Indiana, especially in the unglaciated area, in roadside ditches, low fallow fields (mostly in hard white clay soil), swampy open woods, and along the banks of or on gravel bars in creeks.