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| Perennial sowthistle - Sonchus arvensis L. |
| Home > perennial sowthistle |
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| Perennial sowthistle plant. |
Clasping leaf base of perennial sowthistle |
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| Milky sap of perennial sowthistle. |
Perennial sowthistle flower. |
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Life cycle:Erect, patch-forming perennial.
Stems: Erect, herbaceous stem up to 5 feet tall that branches only near the flowers. Stems are hollow and smooth with ridges and exude a milky sap when damaged. Upper stems may have gland-tipped hairs.
Leaves: Seedling leaves initially develop from a basal rosette from a deep taproot. Lower leaves are alternate, blue-green, 4 to 12 inches long with two to five lobes with prickly teeth on each side, gradually becoming smaller toward the top with a clasping base. Leaves have a thickened midvein and exude a milky sap when damaged. Leaf midvein is not prickly underneath.
Flowers and fruit: Bright yellow ray flowers are 1 to 2 inches wide and found in clustered heads. The seed is enclosed in a single-seeded, narrow, oval, reddish brown, ribbed, wind-disseminated fruit.
Reproduction: Seeds and extensive creeping roots.
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| Lower leaf of perennial sowthistle. |
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| Spiny sowthistle leaf. |
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Similar weeds: Annual sowthistle (S. oleraceus L.)
Differs by having an annual life cycle and short taproot, less prickly leaf margins, and pale yellow, 0.5- to 1-inch-wide flower heads. Leaf midvein is not prickly underneath.
Spiny sowthistle [S. asper (L.) Hill] Differs by having an annual life cycle and short taproot, leaf margins with many sharp prickles, earlike lobes where the leaf attaches to the stem, and flower heads 0.5 to 1 inch wide. Leaf midvein is not prickly underneath.
Prickly lettuce (Lactuca serriola L.) Differs by having an annual or biennial life cycle; fine prickles on leaf margins and sharp prickles on the underside of the leaf midvein; and a many branched, spreading panicle with numerous pale yellow flower heads less than 0.5 inch wide. |
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| Sharp prickles on the underside of the leaf midvein of prickly lettuce. |
Prickly lettuce rosette. |
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