Petasites Miller

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1976, Flora Europaea. Volume 4. Plantaginaceae to Compositae (and Rubiaceae), Cambridge University Press : 186-187

90. Petasites Miller 3

(incl. Nardosmia Cass. )

Dioecious perennial herbs. Leaves usually basal. Scapes with few to numerous scale-leaves and 1 -many capitula, greatly elongating in fruit. Involucral bracts in 1-2 rows. Receptacle flat, without scales. Male capitula with numerous tubular, functionally male florets, usually with a peripheral ring of 1-5 (-10) sterile ligulate or tubular female florets; female capitula with numerous fertile ligulate or tubular female florets and O-5(-8) sterile tubular florets in the centre. Achenes cylindrical, glabrous; pappus-hairs numerous in female, few in male florets, simple.

The key is divided into two parts, one for vegetative and one for flowering material. Vegetative characters refer to mature leaves; cauline scale-leaves comprise those up to the lowest branch of the inflorescence.

Literature: J. Toman, Folia Geobot. Phytotax. (Praha) 7: 381^406 (1972).

K ey to V egetative P lants 1 At least some leaves with lamina cuneate at base 11. sibiricus 1 Lamina cordate to somewhat truncate at base 2 Mature leaves tomentose above 10. doerfleri 2 Mature leaves ± glabrous above 3 Leaves glabrous beneath 5. radiatus 3 Leaves tomentose or lanate beneath, or pubescent on the veins 4 Leaves regularly lobed, with the lobes dentate 5 Lamina without or with 1 lateral vein bordering the sinus 1. albus 5 Lamina with 2-5 lateral veins bordering the sinus 2. hybridus 4 Leaves not with regular, dentate lobes 6 Leaves reniform-cordate, not angular in outline 7 Leaves regularly dentate 8. fragrans 7 Leaves irregularly dentate 9. japonicus 6 Leaves somewhat angular in outline 8 Leaves coarsely dentate or lobed; apices of teeth or lobes (8-)10-20 mm apart 7. frigidus 8 Leaves dentate; apices of teeth 2-6(-10) mm apart

9 Outer scales of leaf-buds strap-shaped, without a rudimentary lamina; leaves almost always 2(-5)-lobed on each side at the base 6. spurius

9 Outer scales of leaf-buds ± ovate, or with a rudimentary lamina; leaves not or very rarely 2-lobed on each side at the base

10 Leaves ± triangular-cordate to hastate, densely whitetomentose beneath 3. paradoxus

10 Leaves usually orbicular-cordate, greyish or greenish beneath, not or sparsely tomentose

11 Leaves sparsely tomentose beneath; petiole-furrow winged 2. hybridus

11 Leaves glabrous beneath except on the veins; petiole-furrow not winged 4. kablikianus K ey to P lants with I nflorescences 1 Bract subtending the lowest inflorescence-branch 1'7-4 cm

wide, and almost as long as the scale-leaves near the base of the scape 2 Scape with more than 7 scale-leaves 9. japonicus 2 Scape with 2-7 scale-leaves 8. fragrans 1 Bract subtending the lowest inflorescence-branch 0-5-1-6 cm

wide, usually much shorter than the scale-leaves near the base of the scape 3 Marginal florets ligulate 4 Involucral bracts glabrous except for the minutely ciliate apex 5 Middle scale-leaves of scape 2-5-4(-7) cm 5. radiatus 5 Middle scale-leaves of scape 5-10-5 cm 6. spurius 4 Involucral bracts pubescent or with a few long hairs 6 Middle scale-leaves of scape 1-2 cm 7 Scapes with 1-3 capitula; involucre 6-7 mm 11. sibiricus 7 Scapes with 3-10 capitula; involucre 8-10 mm 10. doerfleri 6 Middle scale-leaves of scape 2-5-7 cm 8 Involucral bracts pubescent; apex ciliate or somewhat fimbriate 7. frigidus 8 Involucral bracts with a few long hairs; apex not ciliate or fimbriate 8. fragrans 3 Marginal florets tubular 9 Involucral bracts glabrous except for a few hairs round the base and sometimes at apex 10 Middle scale-leaves of scape of male 2-5-5 cm, of female

Г5-4-5 cm; apex of involucral bracts entire, not ciliate

2. hybridus 10 Middle scale-leaves of scape of male 5-5-10-5 cm, of female

5-10 cm; apex of involucral bracts minutely ciliate or fimbriate 6. spurius 9 Involucral bracts minutely pubescent (sometimes glabrescent in fruit) 11 Involucral bracts purplish 3. paradoxus 11 Involucral bracts pale green 12 Heads of glandular hairs on involucral bracts not more than twice as wide as their stalks 1. albus 12 Heads of glandular hairs on involucral bracts 3 times as wide as their stalks 4. kablikianus