In Central Europe, blooming of Helianthus tuberosus lasts from August till November. Afterwards, fertile disk florets are replaced by hairy achenes containing mottled black or brown seeds, 5 mm long x 2 mm wide.
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In Central Europe, blooming of Helianthus tuberosus lasts from August till November. Afterwards, fertile disk florets are replaced by hairy achenes containing mottled black or brown seeds, 5 mm long x 2 mm wide.