Herbs, erect, (15-)30-60 cm tall. Rootstock enlarged or sometimes extensively rhizomatous, brown or dark brown, up to 20 cm × 3-5(-6) mm, branched or not. Stems single or clustered, many branched basally, 3-5 mm thick; sterile stems sometimes present, sometimes overtopping inflorescence. Leaves alternate, often larger toward stem apex; stipules absent; basal scale-leaves few; petiole absent; leaf blade linear to ovate, very variable, (1.5-)2-7 × (0.15-)0.4-0.7(-1.2) cm, base attenuate, cuneate, or truncate, apex acuminate or acute; leaves on sterile branches denser, needlelike, 2-3 × ca. 0.1 cm. Inflorescence a terminal pseudumbel, often with lateral cymes from axils below; cymes mostly dichotomous; primary involucral leaves 3-8, similar to normal leaves to almost orbicular, primary rays 3-8, 2-4(-5) cm; cyathophylls 2, sometimes overlapping at base, usually reniform, occasionally ovate or triangular-ovate, pair often forming complete circle, 0.4-1.2 × 0.4-1 cm, base subtruncate to shallowly cordate, apex shortly acuminate to rounded. Cyathium sessile; involucre campanulate, ca. 3 × 2.5-3 mm, lobes rounded to triangular, tomentose on margin and inside; glands 4, brown, crescent-shaped, usually 2-horned, horns long and acute to short and obtuse or absent, sometimes so tightly incurved that gland looks circular. Bracteoles linear, glabrous. Male flowers many. Female flower: ovary exserted from cup, smooth, glabrous; styles free, persistent; style arms 2-lobed. Capsule trigonous-globose, 5-6 × 5-6 mm, with 3 vertical furrows. Seeds ovoid-globose, 2.5-3 × 2-2.5 mm, yellow-brown; caruncle present, peltate, sessile. Fl. and fr. Apr-Oct. 2n = 40*.
"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 × 3–8 mm, obtuse to mucronate, essentially 1-nerved, the lateral veins very obscure, leaving the midrib at an angle of 15–35°; 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)"