Pieris L.

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 : 315-316

160. Pieris L. 1

Annual to perennial herbs with rigid hairs, most of which have 2-4 small, hooked branches at the apex, sometimes also with spines. Stems usually solitary, usually branched. Leaves sinuatedentate to pinnatisect; cauline often more or less amplexicaul. Capitula few to numerous. Involucral bracts in several imbricate rows. Receptacle pitted, without scales. Ligules yellow, the outer often with a reddish stripe on outer face. Achenes transversely muricate between the ribs, usually narrowed at apex or beaked; pappus of 2 rows of deciduous hairs, the inner plumose, the outer plumose or simple, the outer achenes rarely with short scarious pappus. 1 Outer involucral bracts ovate to ovate-lanceolate, usually wider than the inner 2 Peduncles thickened after anthesis; involucral bracts not pectinate-ciliate or spiny-ciliate 1. aculeata 2 Peduncles not thickened; at least some involucral bracts pectinate-ciliate or spiny-ciliate 3 Outer involucral bracts more than half as long as inner

2. echioides 3 Outer involucral bracts not more than half as long as inner 4 Involucre 10-12 mm 5. spinifera 4 Involucre 15-25 mm 5 Involucre (15—)20—25 mm; beak of achene c. | as long as body 3. comosa 5 Involucre 16-18 mm; beak of achene twice as long as body

4. algarbiensis 1 Outer involucral bracts linear-lanceolate to narrowly lanceolate, similar to the inner 6 Outer achenes with a short scarious pappus, the inner with pappus of plumose hairs 12. willkommii 6 All achenes with pappus of plumose hairs 7Involucral bracts distinctly pectinate-ciliate 7. hispidissima 7 Involucral bracts not pectinate-ciliate 8 Capitula 1-2; involucre 12-20 mm 6. hispanica 8 Capitula more than 2; involucre 8—13(—15) mm 9 Achenes without a beak, not narrowed at apex

11. sprengerana 9 Achenes narrowed at apex or shortly beaked

10 Peduncles often thickened after anthesis; achenes more or less curved, strongly transversely muricate

10. pauciflora

10 Peduncles not thickened after anthesis; achenes straight or slightly curved, weakly transversely muricate

11 Leaves pinnatisect 8. scaberrima

11 Leaves entire to ± dentate 9. hieracioides Sect. helmintia O. Hoffm. Outer involucral bracts ovate to ovate-lanceolate, wider than inner.