Classification
 Nomenclature
Scientific Name:
Carduus pycnocephalus L.
Vernacular Name(s):
Slender thistle; Slender winged thistle
 Description

Annual. Stems usually branched above, (20)–60–100–(150) cm tall, with sparse multicellular hairs below, becoming cobwebby above, ribbed; wing narrowed to 1–2 mm wide between clusters of teeth; teeth 5–15 mm long, in narrowly deltoid to linear clusters; spines 3–8–(10) mm long. Lvs oblanceolate to narrowly deltoid, pinnatifid, (5)–10–30 × (2)–5–15 cm, with multicellular hairs above and cobwebby to woolly tomentum beneath; basal lvs with 3–5 pairs of lobes; lobes dentate; teeth spine-tipped; spines pale, 2–5–(8) mm long. Capitula erect to suberect, falling at fruiting, 10–20 × 5–15 mm, shortly pedunculate or subsessile in terminal clusters of 2–3–(5), also solitary, sessile, and axillary on stems; peduncles 1–2 mm diam. Involucre cylindric to obconic. Outer and middle involucral bracts narrowly lanceolate to deltoid, tapered to a subulate erecto-patent to patently curved spine, without distinct claw and limb, with glandular papillae, and cobwebby hairs at least on margins; apex green, linear; midvein raised in upper 1/2. Inner involucral bracts linear, papillate to puberulent, (1)–3-veined above; apex acute, green with scarious margins, often pink subapically. Corolla pale pinkish purple, (10)–13–15 mm long; lobes 4.5–5.5 mm long; swelling at throat of tube ellipsoid, < 2–(3) mm long. Achenes brown, ellipsoid, 3.5–4 × 1.5–2 mm; pappus 10–12 mm long.

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

 Biostatus
Exotic
 Phenology

Flowering: Oct.–Jan.–(May); Fruiting: Nov.–Feb.–(May)