Euphorbia lathyris L.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Annual or biennial, glabrous and glaucous, to 1 or even 2 m, usually simple to the umbel; cauline lvs opposite, linear or lance-linear, sessile at the truncate or subcordate base, those subtending the umbel similar, usually 4, those of the umbel lance-ovate to deltoid-ovate; involucres 4 mm; fr 1 cm, thick-walled, tardily dehiscent; seeds 4–6 mm, very plump, wrinkled and carunculate; 2n=20. Native of the Mediterranean region, escaped from cult. here and there in our range. May–Sept. (Tithymalus l.; Galarhoeus l.)