Common crupina is an herbaceous winter annual typically growing 1–3 ft (30–90 cm) tall from long taproots. Plants produce rigid, upright stems that are often branched in their upper halves. Seedling leaves are fleshy and round while stem leaves are alternate and deeply lobed with toothed margins and short hairs. Flower heads are produced at stem and branch tips. They are narrow, up to ¾ in (2 cm) long, and produce five purplish-pink florets. The bracts are dark green at first but turn purplish during seed maturation. Seeds are dark brown, barrel-shaped, and have a ring of dark bristly pappus.