Description from Flora of China
Sonchus tataricus Linnaeus, Mant. Pl. 2: 572. 1771; Agathyrsus tataricus (Linnaeus) D. Don; Crepis charbonnelii H. Léveillé; Lactuca multipes H. Léveillé & Vaniot; Lagedium tataricum (Linnaeus) Soják; ?Mulgedium alatoicum C. H. An; M. roborovskii Tzvelev; M. runcinatum Cassini; M. tataricum (Linnaeus) Candolle; S. lactucoides Bunge.
Herbs 15-60 cm tall, perennial, with a taproot, roots shoot bearing. Stem erect; branched apically, glabrous, leafy mainly in basal part. Leaves grayish green to glaucous, rigid, glabrous. Lower and middle stem leaves elliptic, narrowly elliptic, or linear, 6-19 × 2-6 cm, narrowed toward base, pinnatisect, pinnatifid, or coarsely dentate, apex acute to obtuse; lateral lobes 2-5 pairs, subelliptic to triangular, margin entire, denticulate, or spinulose; terminal lobe lanceolate to narrowly triangular, margin entire, denticulate, or spinulose. Upper stem leaves similar to middle stem leaves but smaller and less incised. Synflorescence racemiform to corymbosely paniculiform, almost leafless, usually with numerous capitula. Capitula with ca. 20 florets. Involucre cylindric, 1.1-1.4 × 0.3-0.5 cm at anthesis, to 2 cm in fruit. Phyllaries usually tinged purplish red, glabrous, apex acute to obtuse; outer phyllaries ovate to lanceolate; inner phyllaries ca. 8. Florets usually purplish blue to blue, rarely white. Achene 5-6 mm; body dark gray, columnar to very narrowly ellipsoid, subcompressed, with 5-7 ribs on either side, apically attenuate or contracted into a concolorous or pale stout 1-2 mm beak. Pappus ca. 1 cm. Fl. and fr. Jun-Sep. 2n = 18.
Lactuca tatarica is a very widespread and considerably variable species. Mulgedium roborovskii is considered not to exceed the variation of the species and is included here. Mulgedium alatoicum is tentatively included here from the insufficient original description, as no type material has been seen.
Riverbanks and terraces, by lakes, meadows, by fields, consolidated sand dunes, gravelly places; 1200-4300 m. Gansu, Hebei, Henan, Liaoning, Nei Mongol, Qinghai, Shaanxi, Shanxi, Xinjiang, Xizang [Afghanistan, NW India, Kashmir, Kazakhstan, Kyrgyzstan, Mongolia, Pakistan, C and W Russia, Tajikistan, Uzbekistan; SW Asia, Europe, North America].