Description from Flora of China
Herbs usually 10-150 cm tall, annual. Stems solitary or few, erect, branched from base, middle, or only apically, glabrous or basally often ± hairy, ± leafy or leafless. Basal leaves ± oblanceolate, to 15(-25) × 4(-6) cm, lyrately pinnatipartite or pinnatisect, rarely not divided; glabrous or somewhat hairy, base attenuate into a longer or shorter narrowly winged to ± unwinged petiole-like portion, margin sinuate-dentate; lateral lobes few to many, ovate, rhombic, or elliptic, gradually smaller toward leaf base; terminal lobe ovate, ovate-lanceolate, or obovate, much larger than lateral ones, apex rounded to acute. Stem leaves similar to basal leaves, abruptly or gradually reduced to bracts upward on stem. Synflorescence corymbiform to paniculiform-corymbiform, usually with many to numerous capitula. Capitula with 10-20 florets; peduncle capillaceous. Involucre cylindric, 4-7 mm. Phyllaries abaxially glabrous; outer phyllaries ovate to triangular, longest less than 1.5 mm, apex acute; inner phyllaries adaxially appressed pubescent, midvein subapically plane, margin ± white scarious, apex acute. Anther tube dark green. Style branches yellow upon drying. Achene light brown to dark reddish or purplish brown, fusiform, 1.5-2.5 mm, ribs finely spiculate, apex strongly attenuate. Pappus white, 2.5-3.5 mm. Fl. and fr. Feb-Dec.
Youngia lyrata (= Y. pseudosenecio) and Y. longiflora (= Y. taiwaniana) are treated here as Y. japonica subsp. elstonii and Y. japonica subsp. longiflora, respectively, of a wider Y. japonica, following Babcock and Stebbins (Publ. Carnegie Inst. Washington 484: 97-98. 1937). While Y. japonica subsp. longiflora seems a fairly well-characterized taxon, the delimitation between Y. japonica subsp. japonica and Y. japonica subsp. elstonii appears questionable in view of frequent transitions and a probably scattered distribution pattern.
Mountain slopes, mountain valleys, ravines, forests, forest margins, grasslands, moist areas, by water, stream banks, trailsides, roadsides, disturbed places, densely grassy areas by houses or roads, field margins, as a weed in gardens and fields; below 100-4500 m. Anhui, Chongqing, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hainan, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Shandong, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [present in all easterly and southerly neighboring countries; originating probably from China and introduced pantropically, extending into adjacent subtropical regions].