21. Youngia rosthornii (Diels) Babcock & Stebbins, Publ. Carnegie Inst. Washington. 484: 92. 1937.
多裂黄鹌菜 duo lie huang an cai
Crepis rosthornii Diels, Bot. Jahrb. Syst. 29: 632. 1901; C. japonica (Linnaeus) Bentham f. foliosa Matsuda.
Herbs to 1 m tall or more, ?annual. Stem erect, branched above middle, glabrous, leafy. Basal leaves not seen. Lower and middle stem leaves broadly elliptic to ovate in outline, 11-20 × 7-14 cm, bipinnately compound, primary division pinnatisect; lateral lobes 3 or 4 pairs, opposite to obliquely opposite, oblanceolate, elliptic, irregularly elliptic, or lanceolate, to 5 cm, irregularly pinnatifid to pinnatisect, base ± winged petiolulate, apex acute to acuminate; primary terminal lobe similar in shape and size to lateral lobes; secondary lateral lobes few, irregularly ovate, triangular-ovate, or elliptic. Upper stem leaves similar to middle stem leaves but smaller and with narrower lobes or linear-lanceolate, reduced in size, and undivided. Synflorescence paniculiform-corymbiform, with many capitula. Capitula with ?20-25 florets; peduncle capillaceous, usually 0.5-3 cm. Involucre cylindric, ca. 6 mm. Phyllaries abaxially glabrous; outer phyllaries ovate, longest ca. 1 mm, apex ± acute; inner phyllaries ca. 8, adaxially ± appressed pubescent, midvein subapically plane, margin narrowly white scarious, apex acute. Anther tube green. Style branches yellow upon drying. Achene dark brownish purple, fusiform, ca. 2 mm, ribs apically finely spiculate, apex attenuate. Pappus white, 3-4 mm. Fl. and fr. Jun-Oct.
● Mountain slopes; 500-1500 m. Chongqing, Guangdong, Hubei, Sichuan, Zhejiang.
Distinction of Youngia rosthornii from Y. heterophylla is not without doubt because forms of the latter occur that approach the leaf division of the former. Youngia rosthornii may represent only an extreme form of Y. heterophylla.