Euphorbia obtusata Pursh. Phen: Apr-Jul. Hab: Rich bottomland forests. Dist: Sc. PA west to IN and IA, south to GA, SC and TX.
Origin/Endemic status: Native
Taxonomy Comments: We maintain E. obtusata as distinct from E. spathulata, pending further research. See Riina et al. (2016) for a discussion on regional variation in a broader E. spathulata (particularly e. US vs. w. US); they describe various treatments that have maintained this taxon at species level but also mention surprisingly widespread but perhaps somewhat isolated instances of morphological overlap. Work is also needed to solidify the eastern and western limits of E. spathulata and E. obtustata, respectively. The distribution of both taxa in Georgia, for instance, needs clarification; we maintain the identification of three piedmont specimens by Jim Allison as E. obtusata (2120; 2837; 6375).
Synonymy: = C, F, G, Il, Pa, RAB, W, WV, Ward (2023) in Weakley et al. (2023, in press); = Galarhoeus obtusatus (Pursh) Small – S; < Euphorbia spathulata Lam. – FNA12, GrPl, K1, K3, K4, Govaerts, Frodin, & Radcliffe-Smith (2000)