Sonchus pulchellus Pursh, Fl. Amer. Sept. 2: 502. 1813; Lactuca pulchella (Pursh) de Candolle; L. tatarica (Linnaeus) C. A. Meyer subsp. pulchella (Pursh) Stebbins

Leaf blades 3–12(–18) cm × 5–25(–35+) mm. Involucres 12–15+ mm. Cypselae: bodies 4–5+ mm, beaks 0–1 mm; pappi 7–9(–12+) mm. 2n = 18.

Flowering Jun–Sep. Calcareous sites, clearings in forests or shrublands, meadows, roadsides, stream banks, other wet sites; 800–3200 m; Alta., B.C., Man., N.W.T., Ont., Que., Sask.; Alaska, Ariz., Calif., Colo., Idaho, Ill., Ind., Iowa, Kans., La., Maine, Mich., Minn., Mo., Mont., Nebr., Nev., N.Mex., N.Y., N.Dak., Ohio, Okla., Oreg., Pa., S.Dak., Tex., Utah, Wash., Wis., Wyo.

The type of Mulgedium pulchellum may be conspecific with that of M. tataricum (Linnaeus) de Candolle, a Eurasian species. Or, if "perennial" plus "Fl. blue" constitutes sufficient description for valid publication of the name Lactuca oblongifolia Nuttall (1813), then a new combination in Mulgedium based on that name may be appropriate for what is here called M. pulchellum. Presence of Mulgedium pulchellum in Texas is based on a single, early collection.