白头蟹甲草 bai tou xie jia cao

Senecio leucocephalus Franchet, J. Bot. (Morot) 8: 360. 1894; Cacalia leucocephala (Franchet) Handel-Mazzetti.

Rhizomes procumbent, with numerous tomentose fibrous roots. Stem solitary, erect, often purple tinged, conspicuously striate, 40-80 cm tall, naked below, glabrous, white arachnoid or later glabrescent above. Leaves long petiolate; lower leaves fallen by anthesis; petioles 4-9 cm, not winged, glabrous or subglabrous. Median leaves adaxially green, ovate-triangular or hastate-triangular, rarely cordate, 8-12 × 18-14 cm, abaxially white or gray-white arachnoid, adaxially hispidulous, palmately 3-5-veined, lateral veins upward furcate, veins prominent on both surfaces, base cordate or truncate, margin irregularly serrate, teeth mucronulate, apex shortly acute or caudate. Upper leaves smaller, petioles shorter. Capitula many, terminal and in upper leaf axils, arranged in narrow panicles; peduncles 2-17 mm, with 2 or 3 linear bractlets, densely tomentose. Involucres cylindric or cylindric-campanulate, 8-10 × 4-5 mm; phyllaries 5, oblong or oblong-lanceolate, 8-10 × 2-4 mm, white lanate, margin scarious, apically obtuse. Florets 10-13; corolla yellow, 8-11 mm, with slender ca. 3 mm tube and tubular limb; lobes lanceolate. Anthers exserted from corolla, basally long caudate. Style branches excurved, truncate, papillose. Achenes cylindric, 5-6 mm, glabrous, ribbed. Pappus white, 6-8 mm. Fl. Aug-Sep, fr. Oct.

● Forest understories, forest margins, grasslands; 1200-3000 m. Chongqing (Chengkou, Wushan), W Hubei.

Parasenecio leucocephalus is easily distinguished by its stems and leaves abaxially densely arachnoid; phyllaries rather broad, densely white lanate; and florets 10-13.