Petasites in Flora of China @ efloras.org

102. Petasites Miller, Gard. Dict. Abr., ed. 4. [1056]. 1754.

蜂斗菜属 feng dou cai shu

Nardosmia Cassini.

Herbs, perennial, subdioecious. Rhizomes as stems robust, node-shaped or at least more robust in lower part. Basal leaves long petiolate; blade broadly cordate or reniform-cordate, margin incised or basally lobed, parallel to furcate. Stem leaves bract-shaped, sessile, subamplexicaul. Capitula radiate, disciform or discoid, hetero- or homogamous. Involucres campanulate, basally with bractlets; phyllaries 1-5-seriate, equal. Receptacle flat, glabrous, peltate. Florets in female capitula fertile; corolla filiform, apex obliquely truncate or ± indistinctly radiate, or lamina longer; functionally male florets: corolla tubular, 5-toothed; anthers entire or obtuse at base, or rarely shortly hastate; style apically clavate, conical, 2-fid, style in female florets filiform, 2-fid. Achenes cylindric, glabrous, ribbed. Pappus of many bristles, white.

Nineteen species: Asia, Europe, North America; six species (two endemic) in China.

1 Leaves palmate-pinnately divided (segments not to middle), reniform, terminal segment 3-lobed, segments with incised, mucronulate teeth; involucres ovate-oblong, synflorescences corymbose and densely paniculate; female florets indistinctly radiate. 1 P. tatewakianus

+ Leaves undivided, angular or toothed, ± reniform (2)

2 (1) Capitula numerous, arranged in cymose panicles or panicles, bracteal leaves ovate-oblong, lanceolate, or ovate-lanceolate, apex acute or acuminate (3)

+ Capitula few, racemose or corymbose, rarely 2- or 3-branched in lower part, bracteal leaves oblong or ovate-lanceolate (4)

3 (2) Involucres of female capitula campanulate, 8-9 mm, style exserted from corolla, male capitula with peduncles 10-15 mm, peduncles of female capitula stout, 7-15 mm. 2 P. formosanus

+ Involucres of female capitula subcylindric, 10-12 mm, peduncles as long as capitula or longer, to 8 cm. 3 P. tricholobus

4 (2) Leaves papery, reniform, 3-5.5 × 5-9 cm; capitula 6-9, arranged in corymbs; peduncles slender, 1-4(-6) cm; involucres obconic, 8-10 mm, female florets shortly radiate, 2- or 3-toothed. 4 P. rubellus

+ Leaves thin, larger, deeply cordate or orbicular-reniform; capitula numerous, arranged in corymbs or racemes; peduncles ca. 5.5 cm (5)

5 (4) Bracteal leaves oblong or ovate-lanceolate, apex obtuse; capitula arranged in dense, terminal corymbs, racemose after anthesis; phyllaries narrowly oblong, apex obtuse. 5 P. japonicus

+ Bracteal leaves broadly ovate, stem leaves and lower bracteal leaves lanceolate, apex acuminate; capitula racemose; phyllaries 11-15, linear, apex obtuse or slightly acute. 6 P. versipilus

Lower Taxa