Strong-rooted, vigorously colonial perennial, erect, 3-7 dm, glabrous, usually with numerous alternate flowering branches below the umbel; cauline lvs linear to lance-linear or narrowly oblanceolate, mostly 3-8 cm נ3-8 mm, obtuse to mucronate, essentially 1-nerved, the lateral veins very obscure, leaving the midrib at an angle of 15-35л lvs subtending the umbel shorter and broader, lanceolate to ovate, those of the umbel opposite, broadly cordate or reniform; rays of the primary umbel mostly 7-15; fr 3-3.5 mm, finely granular; seeds ellipsoid, 2-2.5 mm; 2n=20, 60, 64. Native of Eurasia, widely established in N. Amer. from New England to the Pacific, s. to Md., Ind., Io., and Colo. Summer. (Tithymalus e.; Galarhoeus e.; Euphorbia intercedens; E. podperae; E. virgata, at least as applied to N. Amer. plants)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.