Spotted knapweed – Centaurea stoebe

Spotted knapweed

Centaurea stoebe L. ssp. micranthos (Gugler) Hayek
Asteraceae (Aster family)

Life cycle
Biennial or short-lived perennial.

Leaves
First-year leaves originate from a basal rosette,followed by a flowering stem in the second year. Basal leaves are deeply and irregularly lobed on long stalks; stem leaves are alternate and finely dissected. Leaves are grayish green and roughly hairy.

Stems
Erect, wiry stems elongate during the second year, up to 6 feet tall with multiple branching. Stems are roughly hairy and often green to purple-striped.

Flowers and fruit
Terminal and axillary heads consist of purple to pink disk flowers above encircled by distinctly black-tipped bracts below. The seed is enclosed in a single-seeded, olive-green to brown fruit with a bristly pappus that can attach to animals for transport.

Reproduction
Seeds.

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Spotted knapweed flower
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Spotted knapweed rosette
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Spotted knapweed leaf
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Spotted knapweed stem

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