Euphorbia obtusata Pursh
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Glabrous annual, 2–7 dm, simple to the umbel or with a few lateral branches; cauline lvs oblong-oblanceolate, 1.5–4 cm, very obtuse, finely serrulate, subcordate and somewhat clasping at the sessile base; lvs subtending the primary umbel shorter and broader, those of the umbel broadly ovate; rays of the primary umbel usually 3; involucres 1.5 mm, strictly glabrous outside; styles separate to the base, each bifid a third to half its length; fr 3–3.5 mm, verrucose; seeds thickly lenticular, 2–2.5 mm and nearly as wide, smooth or obscurely reticulate. Woods; Pa. to Ind. and Io., s. to S.C. and Tex. Apr., May. (Tithymalus o.; Galarhoeus o.)