This annual is known from across east-central states, generally growing in disturbed soil of fields or thin woods on bottomlands and adjacent uplands (F, Cr, Y, W). It appears to have declined greatly, and it is generally rare except perhaps locally in "rich bottomland forersts" of the mid-Atlantic Coastal Plain and adjacent Piedmont (NS, W). It also remains locally frequent in s. Ohio, including near Nabalus crepidineus and Trifolium stoloniferum in Hamilton Co. (D. Boone, pers. comm.). There are only about 12 recorded localities in Ky., with just two observations after 1980 (see also M). Some recent treatments and listings (e.g. Ch, K, NS) have combined obtusata with E. spathulata Lam. [= E. dictyosperma Fisch. & Mey], which is a more western species of generally drier sites. E.spathulata has been distinguished using various characters (F, Cr, Y, W; Weakley ey al. 2023): seeds 1.3-1.8 mm long (versus 1.7-2.5 mm), with a distinctly alveolate surface (versus smooth or obscurely reticulate); involucral bracts with "glands yellow, one of them replaced by a small lobe or tuft of hairs" (F--versus "red or scarlet, all present"); cyathia with involucre 0.6-0.9 mm long (versus 1.2-1.5 mm); dichasial bracts ("floral leaves") truncate to subcordate (versus cordate-clasping). Typical spathulata is unknown in Ky. (despite mapping of W), but it has been reported from c. Tenn. (Ch) and it may be expected elsewhere in eastern states, at least as an adventive (W). The Ky. and Tenn. records of these two taxa (including SERNEC) need more assessment to distinguish them. The related species, E. purpurea (Raf.) Fern. [= E. darlingtonii Gray], is a much more robust, rhizomatous perennial with leaf blades that are mostly 5-10 cm long (versus 1-5 cm), entire (versus partly serrulaste) and minutely downy beneath (versus glabrous or nearly so). It is a globally rare species known from "rich or swampy woods and thickets" in or near the central Appalachians, including Adams and Pike Co., Ohio (F, K). Species in the obtusata-helioscopia group differ from other species of subgenus Esula as follows: glands of involucres transversely oval to subreniform (versus crescent -shaped or 2-horned); also, leaves are serrulate in most species (versus only entire).