52. Euphorbia lathyris L., Sp. Pl. 457. 1753. Boiss. in DC.,Prodr. 15(2): 99. 1862; Prokh. in Fl. U.R.S.S. 14: 479.1949.
An erect, glabrous, glaucous annual or biennial, thick-stemmed herb up to 1.5 m tall, but more usually 0.5-1 m tall, often with numerous axillary leafy shoots arising near the middle of the stem. Stem-leaves opposite, decussate, sessile; leaf-blades linear-lanceolate, 3-10 x 0.4-1.7 cm, acute or subacute and mucronulate, shallowly cordate at the base, entire, penninerved, dark blue-green. Pseudumbel (0-) 2-4-rayed, sometimes many times bifid; axillary rays 0 or few below the pseudumbel; pseudumbel-leaves 2-4, opposite or whorled, ovate-lanceolate or oblong-lanceolate, slightly smaller than the upper stem-leaves; ray-leaves opposite, triangular-ovate, acutely acuminate, pale green, shorter and broader than the pseudumbel-leaves. Cyathia pedunculate, pale green, the peduncle purplish. Glands 2-homed, the horns divergent, spathulate, yellowish-green blotched with purple. Fruit hexalobate-subglobose, 0.9-1.3 x 1.3-1.7 cm, smooth when fresh, wrinkled with age, with a spongy mesocarp and woody endocarp. Styles erect or recurved, 2.5-3 mm long, ± free, deeply bipartite, the stigmas slightly thickened. Seeds ovoid, somewhat laterally compressed, truncate at both ends, obliquely so at the apex, 4.5-5 x 3-3.5 x 3.5-4 mm, vermiculate-rugulose, pale grey or brownish, with a small patelliform caruncle.
Fl. Per.: Apr.
Syntypes: France and Italy, on field-margins, specimen no. 630/32 in Herb. Linn. (LINN); Hort. Cliff. no. 13 (BM,!).
Distribution: Widespread, but nowhere known to be definitely native. Atlantic Islands, Europe, NW & NE Africa, Caucasus, China, Japan, N. & S. America. In waste places. 4500'/1370 m.