Silybum marianum (L.) Gaertn.

Annual or biennial. Stems branched above, ridged, with sparse mealy hairs at least above, 0.5–2 m tall, not winged. Lvs elliptic to lanceolate, lyrate-pinnatifid to pinnate, sinuate, coarsely dentate, green with conspicuous white markings along veins, (10)–20–60 × (5)–10–30 cm, with sparse short mealy hairs on lamina, and sparse long tangled multicellular hairs on midrib; base amplexicaul, auriculate, with very spinous margins; prickles marginal, yellowish, spreading, 5–12 mm long. Capitula ovoid, erect, 4–6 × 5–7 cm, solitary, terminal and pedunculate, and also sessile in axils of uppermost lvs; peduncles with appressed cobwebby tomentum. Involucral bracts sparsely covered with short mealy hairs; margins with sparse cobwebby hairs. Outer bracts leaflike, obovate with spinous apex and margins. Middle bracts oblong; appendage ovate, subulate, with spinous margins and a long spreading to recurved apical spine. Inner bracts lanceolate; appendage becoming linear-lanceolate, entire. Corolla reddish purple, 20–28 mm long; lobes unequal, 4–6 mm long. Anther filaments joined at margins into a tube which encloses the basal appendages of the anthers. Style exserted 1–2 mm beyond corolla lobes. Achenes brown or black-streaked, obovoid, weakly transversely flattened, smooth, c. 6 × 3 mm; outer pappus bristles scabrid, c. 15 mm long; inner hairs very fine.

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

Flowering: Nov.–Jan.–(Feb.); Fruiting: Dec.–Mar.