Description from Flora of China
Herbs, annual, biennial, or perennial. Stem erect, not or sparsely branched below synflorescence, leafy. Leaves pinnate to undivided. Synflorescence corymbiform or paniculiform, with few to numerous capitula. Capitula with usually 70-300 florets. Involucre campanulate to broadly campanulate, as peduncle often with stipitate glandular hairs and basally ± white tomentose. Phyllaries green, glabrous or glandular hairy; outer phyllaries in several series, gradually longer centripetally, ± imbricate with longest 1/2-3/4 as long as inner ones; inner phyllaries 8-15, ± equal in length, linear-lanceolate to linear. Receptacle naked. Florets yellow. Achene brownish, ovoid to ellipsoid, compressed, narrowed toward both ends, with (4 or)5 main ribs usually accompanied by 2 secondary ribs, smooth or transversely wrinkled. Pappus white, caducous or persistent, of numerous soft fine outer bristles intermixed with some thicker often ± easily caducous inner bristles.
The revised, wider circumscription of Sonchus is based on molecular phylogenetic analyses by S. C. Kim et al. (Molec. Phylogen. Evol. 44: 578-597. 2007) and includes several former segregates, which, however, are not present in China.
The main diversity of this genus is in E Africa, the W Mediterranean region, and the mid-Atlantic archipelagos.
About 90 species in its wider circumscription: Africa, Asia, Australia, Europe, Pacific islands (New Zealand); five species (two introduced) in China.
(Authors: Shi Zhu (石铸 Shih Chu); Norbert Kilian)