Origin: Introduced.

General: Annual, weedy, non-native plants with prickly leaves. The plants have milky-white sap.

Has been declared a noxious weed in Saskatchewan.

Flowers: Flower heads in an open terminal panicle, are pale yellow, ligulate, flower heads measured at 13 mm diameter. The ends of the ligules with 4 or 5 teeth. Bracts grow in several series, and inner bract measured at 5 mm long. The flower heads close up by noon.

Leaves: Cauline leaves are alternate, oblong, and are twisted at the base to lie more or less in a vertical plane. We measured a leaf at 82 mm long by 30 mm wide. The underside of leaf midribs bear a row of spines.  The cauline  leaves clasp the stem, and are eared at their base.

Height: Height listed in Budd's Flora to 100 cm tall, we measured plants to 78 cm tall.

Habitat: Roadsides, waste ground, cultivated land.

Abundance: Common.

When and where photographed: Photos taken July 22nd,on prairie about 200 km west of Regina, SK, and August 23rd, weedy shrub bed, Wascana park in Regina, SK.