Scientific Name:
Onopordum acanthium L., Sp. Pl. 827 (1753)
Vernacular Name(s):
Cotton thistle; Giant thistle; Scotch thistle

Taprooted biennial. Stems branched above, covered with dense, white felted tomentum, 1–3 m tall, with broad dentate spiny wings 5–18 mm wide. Lvs deltoid to ovate to lanceolate, shallowly pinnatifid, coarsely dentate, grey-green, 20–30 × 15–20 cm, with dense fine felted tomentum above and beneath; prickles marginal, yellowish, spreading, 5–10 mm long. Capitula broadly ovoid, waisted at flowering, erect, 2–4–(5) × 2–4–(5) cm, solitary; peduncles elongating just before anthesis, 5–15–(25) cm long. Involucral bracts linear-subulate, 2–3 mm wide at base, the outer and middle with dense cobwebby tomentum; apex spinous, spreading to suberect. Corolla purple or white, 20–24 mm long; lobes unequal, 5–7 mm long. Style exserted 3–4 mm beyond corolla lobes. Achenes dark, narrowly obovoid to clavate, weakly transversely flattened and 4-angled, rugose, 5–6 × 2–2.5 mm; ribs 4, pale; pappus bristles scabrid, 5–10 mm long.

[From: Webb et al. (1988) Flora of New Zealand. Volume 4.]


Flowering: Dec.–Feb.; Fruiting: Jan.–Mar.

Biosecurity New Zealand 2012: Regional Pest Management Strategies Database.
Linnaeus, C. 1753: Species Plantarum. Impensis Laurentii Salvii, Stockholm.