Stout annuals, stems branching, herbage and sepals are heavily armed with yellow spines, herbage is not glandular but densely hairy with stellate (star-like) hairs.
Very spiny plants with pinnately lobed leaves. Sepals grow larger after flowering and enclose the fruit. Herbage and flowers are not glandular; flowers and anthers are yellow.
Habitat
Roadsides, fields, overgrazed pastures and disturbed areas.
Flower Characteristics
To 1 inch wide. Shaped like a star with 5 crinkly lobes and 5 yellow anthers in the center. Few flowers clustered along the end of spiny flower stalks.
Leaf and Stem Characteristics
Leaves to 6 inches long and 2 inches wide, 5 to 7 pinnate lobes, borne on stout petioles to 2 inches long. Spines on stalks and vein backs.
Fruit and Seed Characteristics
Spiny sepals grow to enclose the fruit.
Seeds flattened, ovoid, dark brown and deeply pitted.