Onopordum illyricum

Linnaeus

Sp. Pl. 2: 827. 1753

Common names: Illyrian thistle
Treatment appears in FNA Volume 19. Treatment on page 88. Mentioned on page 87.
Plants 50–250 cm, herbage canescent-tomentose throughout. Stems: wings 0.5–2 cm wide. Leaves 10–50 cm, margins shallowly to ± deeply 1–2-pinnatifid with 8–10 pairs of triangular lobes. Heads mostly borne singly at branch tips. Involucres 30–60 mm diam (excluding spines) ± spheric, bases truncate to concave. Phyllaries lanceolate to ovate, bases 3–8 mm wide, glabrous or ± cobwebby-tomentose, spines to 5 mm. Corollas purple, 25–35 mm. Cypselae 4–5 mm; pappi of many whitish, plumose bristles 10–12 mm. 2n = 34 (France).

Phenology: Flowering summer (Jun–Aug).
Habitat: Grasslands, fields, roadsides, oak woodlands
Elevation: 200–500 m

Distribution

V19-37-distribution-map.gif

Calif., s Europe (Mediterranean region), introduced in Australia.

Discussion

Illyrian thistle is considered to be a noxious weed in California where efforts to eradicate it from the state’s flora have been implemented. This species has also invaded rangelands in Australia, where it is introduced.

Selected References

None.

Lower Taxa

None.