Prenanthes laevigata Blume
Stems robust, to 90 cm long; cauline leaves few, stem and leaves sparsely covered with minute multicellular scale-like hairs. Radical leaves broadly oblong to oblong-lanceolate, to 5-25(-55)×0.8-5 cm, apex usually obtuse, base subsessile or petiolate, usually pinnatilobed; cauline leaves 1-3, lanceolate or linear-lanceolate, gradually narrowed to a petiole-like base. Inflorescence many headed, corymbose or pseudo-umbellate. Heads 8-10 mm across, ca. 10-flowered; peduncle slender, 6-8 mm long. Involucre cylindric, ca. 5 mm long, outer bracts calyculate, 1-1.5 mm long, ovate-lanceolate, inner bracts 8-10, linear-lanceolate, becoming thick-keeled toward base. Florets 8-11; corolla yellow, 6.5-7.5×1.5-2 mm. achenes narrowly lanceolate, slightly compressed, 4-5 mm long. Pappus 2.5-3 mm long, bristles unequal. Chromosome number, 2n = 14 (Peng & Hsu, 1978).
TAIPEI: Hopingtao, Leu 1243; Pinglin, Peng 10581. ILAN: Ssuyuan, Peng 5583. TAOYUAN: Peichatienshan, Peng 10116; Paling, Peng 11031. HSINCHU: Hsinfeng, Peng 10383; Hengshan, Wang 765. MIAOLI: Kuanwu to Leshan, Peng 9405. TAICHUNG: Hoping, Shen 467. NANTOU: Tungpu to Kuankao, Peng 8072; Tatachia, Peng 11460. CHIAYI: Alishan, Ho 1138. TAINAN: Yangnu Lake, Chen 530. KAOHSIUNG: Tengchih, Chen 574; Maolin, Chen 625. PINGTUNG: Wutai, Lin 393; Nanjenshan, Wang 510. TAITUNG: Haituan, Yakou, Peng 11708; Lanyu Is., Peng 6721. HUALIEN: Tali to Tatung, Chen 157; Lanshan, Peng 9895.
Southeast Asia, Japan and southern China. Taiwan, widespread from the seacoast to mid elevations, in littoral areas, riversides and on gravelly limestone, 0-2,300 m.
Ixeridium laevigatum is exceedingly variable in plant size and dissection of leaves.