Fig 208. [Corn Sow-Thistles. Sonchus arvensis] L.

Corn Sow-Thistles. Sonchus arvensis L. Flowers yellow; achenes dull, dark reddish brown, oblong, extremities blunt, slightly flattened, bearing four coarse, fold-like ridges, with two smaller ridges between each of the two large ones, transversely wrinkled, 2.5–3 mm. long. This species is a perennial spreading by roots-stalks as well as by seeds. Introduced in Europe.

Fig 209. [Spiny Sow-Thistle. Sonchus asper] (L.) Hill.

Spiny Sow-Thistle. Sonchus asper (L.) Hill. Flowers pale yellow; achenes dull straw-color to reddish brown, much flattened, obovate, oblong, extremities blunt, each side bearing 3–5 vertical ridges, surface nearly smooth, 2.5–3 mm. long. Introduced from Europe.

Fig 210. [Common Sow-Thistle. Sonchus oleraceus] L.