Onopordum acanthium L. ssp. acanthium

Family: Asteraceae, Tribe: Cynareae

Pertinent Synonyms & Notes (particularly those used in California; go to GRIN for other synonyms)


Pertinent Common Names (particularly those used in California; go to GRIN for other common names)

Scotch thistle

Primary Disseminule Type


Description (diagnostics are in brown)

Fruit a cypsela, broadly obovate, sometimes slightly curved, mildly compressed and slightly 4-sided (cross-section elliptic to polygonous), 4–6 mm long x 2–3 mm wide x 1.6–1.9 mm thick. Surface light to dark grayish-brown with brown to black mottling, glabrous, dull, with wavy transverse ridges, often with 4+ irregularly-placed, thin longitudinal ridges. Pappus deciduous as a fused ring (and therefore typically missing), bristles numerous, equal, (5)7–10(12) mm long, minutely barbed, pink to reddish.

Style base cylindrical to polygonal, surrounded by a slightly depressed ring which is the apical scar.

Fruit attachment scar ± basal, whitish, often partially obscured by a hardened elaiosome.

Risk Assessment (codes in yellow or red indicate cause for concern; assessments are current as of mid-2011; click AUQP, NZBORIC, or NZBPI for access to the most recent versions of these databases and possible assessment changes)