Euphorbia esula L.
NOTE: This species is actionable only when found in field or vegetable seed for planting; tolerance applies.
Fruit a capsule, 3-chambered, 1 seed per chamber. Seeds broadly ovate to broadly oblong, subterete, 2.0–3.0 mm long, (1.1)1.2–1.6(1.8)mm in diameter; base of seed flat, oblique, with hilum usually obscured by persistent cartilaginous caruncle. Caruncle wrinkled, glossy to dull and crusty, orangeish to cream-colored, sessile, appressed obliquely to testa or extending out +/– horizontally. Raphe a prominent dark, thin, single or double line, extending longitudinally from the hilum to the chalazal area at apex. Chalaza prominent, round, slightly depressed. Testa lustrous, minutely reticulate and appearing smooth, greyish-white to greyish-brown and usually mottled or flecked with brown. Hilum darker than testa, narrowly wedge-shaped, grading into raphe. Embryo spatulate; endosperm readily visible.
Euphorbia lucida Waldst. & Kit. (non-FNW)
widespread in Europe; also found in China, Iran, Argentina, Canada, and the United States
native to most of mainland Europe excluding the Scandinavian countries
sub-tropic to sub-arctic climates, tolerating very dry as well as flooded conditions; grows best in coarse-textured soils; found in rangeland, riparian areas, waste areas, disturbed sites, roadsides, fields, and pastures
Euphorbia esula is a deep-rooted perennial herb, up to 1 m tall. It is a very aggressive and difficult to control plant; roots or root fragments as deep as 2.8 m can produce shoots for many years under adverse conditions. Its seed is dispersed by explosively bursting fruit. The plant’s latex is toxic to cattle and horses (but not to sheep and goats). Infestations may result in severe reduction of available grazing land and major losses in livestock production. Euphorbia esula is one of ten species covered under the Federal Seed Act for which tolerance is applicable to its introduction (7 CFR 361.6(a)(2)).