Centaurea solstitialis
Asteraceae
Yellow Starthistle
Spreading clump lightly coated with cobweb-like hairs. Stems upright and winged under leaves, stiff, much divided. Lower leaves linear, lobed; upper leaves becoming smaller until scale-like. Flower heads single, develop in shallow cup of brown bracts. Bracts tipped with very long, stiff, yellow spines surrounded by 2–4 short spines. Disk flowers elongated to create petal-like, fluffy flower head. Grows in disturbed soils, fields, along roads. Common at low and mid elevations. Highly aggressive noxious weed.
- Rarity: Common
- Flowering Time: Early Summer, Mid Summer, Late Summer
- Flower Form: Smooth leaves, Thistle
- Life Cycle: Annual
- Height: 8–32 inches
- Habitat: Disturbed, Meadow
- Native: No
- Also Known As: St. Barnaby's Thistle
