Prenanthes chinensis Thunb.
Perennials; stems erect, not stoloniferous, 15-40 cm long, branched. Lower cauline leaves few (2-4), remote, glabrous, oblanceolate, 8-25 × 0.5-2 cm, apex acute or rarely obtuse, base narrowed into winged petiole, margins subentire or irregularly dentate; median cauline leaves lanceolate, 5-9 cm long, apex acuminate, margins entire to mucronulate-dentate, irregularly cleft or pinnatifid; uppermost leaves few, bract-like, 1-3 mm long. Heads many, in loose corymbs. Involucre tubular, 6-8×3-5 mm, bracts nearly equal, outer bracts calyculate, ovate, 1-1.5 mm long, apex obtuse, white margined, inner bracts 8, oblong-lanceolate, obtuse, base becoming thick keeled. Florets 20-25; corolla yellow, 9-12× ca. 2 mm. Achenes 4-6 mm long, 10-winged, beak slender, ca. 3 mm long. Pappus 4-5 mm long. Chromosome number, 2n = 16 (Peng & Hsu, 1978).
TAIPEI: Nankang, Leu 3; Shihmen, Peng 9340. ILAN: Tatung, Peng 6249; Ssuyuan, Peng 5584. TAOYUAN: Fuhsing, Peng 10306. HSINCHU: Chupei, Peng 11502; Hengshan, Wang 767. MIAOLI: Hsihu, Peng 13961; Shihtan, Peng 13940. TAICHUNG: Houli, Peng 11498; Chika Lodge, Peng 9616. NANTOU: Shuili, Peng 6459. CHIAYI: Tatachia, Peng 8975. TAINAN: Tucheng, Peng 13174; Matou, Peng 10538. PENGHU: Wangan, Leu 2070; Hsiyu, Peng 12756. KAOHSIUNG: Liukuei, Peng 11200. PINGTUNG: Tahan Forest Road, Leu 640; Santimen, Peng 10241. TAITUNG: Taimali, Chen 509. HUALIEN: Hoping Forest Road, Peng 5815; Pilu, Peng 9252.
Southeast Asia, Korea, Japan and China. Taiwan, widespread throughout the island.
Ixeris chinensis is a highly polymorphic species and thus various infraspecific taxa have been proposed. In the first edition of Flora of Taiwan, two such taxa, I. chinensis var. saxatilis and I. chinensis f. lacerrima, were taken up. The former is represented by plants with ciliate-serrulated or pinnatifid leaves, while the latter is represented by plants with irregularly clefted leaves. Ixeris chinensis is an exceedingly variable species in Asia. Detailed studies are required to reveal the total ranges of variation of this taxon in relation to its geographical ranges, underlying ecological condition, and possibly its population structure in Taiwan.