Citation: Curtis, Fl. Lond. 2,6:t. 55 (1793).

Synonymy: Not Applicable

Common name: Slender thistle, winged slender thistle.

Description:
Annual herb 50-150 cm high; basal leaves few, oblanceolate, 5-20 cm long, 2-8 cm wide, pinnatipartite with triangular lobes, faintly variegated, green and pubescent above, cobwebby below; margins with spines at the angles; stems erect, usually branched, cobwebby, with continuous wings broken into spiny lobes to 10 mm wide; cauline leaves oblanceolate to lanceolate, 5-15 cm long, 2-6 cm wide, pinnatifid with 5-8 pairs of triangular lobes, decurrent.

Capitula sessile in dense clusters of 3-9 at the ends of the stems, erect to patent, 0.6-1 cm diam.; involucre cylindrical, 1.5-2 cm long; bracts erect, narrowly lanceolate, glabrous to sparsely cobwebby; outer ones spinetipped, green; intermediate ones spine-tipped with scarious margins; inner ones slightly longer than the florets, not spiny; corollas 10-14 mm long, purple.

Achenes 4-5 mm long; pappus bristles subequal, 11-13 mm long.

Published illustration: Cunningham et al. (1982) Plants of western New South Wales, p. 724.

Distribution:  A common weed of pasture and disturbed ground. S.Aust.: FR, EA, EP, NL, MU, YP, SL, KI, SE.   W.Aust.; N.S.W.; Vic.; Tas.   Native to Europe. Conservation status: naturalised Flowering time: Oct. — Nov.

SA Distribution Map based on current data relating to specimens held in the State Herbarium of South Australia

Biology: Carduus tenuiflorus and C. pycnocephalus are closely related and difficult to distinguish, especially in the case of the populations naturalised in Australia. The majority of South Australian collections are referrable to C tenuiflorus.

Author: Not yet available