Northern Prairie Wildlife Research Center
Prickly Sowthistle (Sonchus asper)
- Family: Aster (Asteraceae)
- Flowering: May-October.
- Field Marks: This prickly species differs from other sowthistles by its flowering heads less than 1 inch in diameter and wrinkled achenes.
- Habitat: Disturbed soil.
- Habit: Annual herb with a short taproot.
- Stems: Erect, usually branched, smooth or slightly hairy, up to 4 feet tall, with latex.
- Leaves: Alternate, deeply divided, with prickly teeth, up to 1 foot long, with a pair of rounded auricles at the base; latex present.
- Flowers: Several crowded into heads, with several heads per plant; each head less than 1 inch in diameter and subtended by several rows of pointed, green bracts; all flowers ray-like, yellow.
- Sepals: 0.
- Petals: Yellow, united to form a ray, notched at the tip.
- Stamens: 5.
- Pistils: Ovary inferior.
- Fruits: Achenes up to 1/8 inch long, wrinkled.
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