perennial sowthistle

Sonchus arvensis L.

Appearance: Sonchus arvensis is a perennial herbaceous plant. Stems can reach 4.9 ft. (1.5 m) in height and contain milky sap.
Foliage: Leaves are sessile, alternate, clasping, up to 12 in. (30.5 cm) long and decrease in size further up the stem, margins undulate with sharp spines.
Flowers: Flowering occurs in June to October, when yellow, tight, dandelion-like flower heads develop at the tips of the branches. Flowers open 2-3 hours after sunrise and close about noon.
Fruit: Fruits are reddish, ribbed and have a tuft of hair at the top.
Ecological Threat: Sonchus arvensis occurs along roadsides, railroads and other disturbed habitat. It is native to Eurasia.

Plant(s) in flower
OSU Extension Slide Set Archives , The Ohio State University, Bugwood.org
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Flower(s)
Tom Heutte, USDA Forest Service, Bugwood.org
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Foliage
Steve Dewey, Utah State University, Bugwood.org
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Plant(s)
Steve Dewey, Utah State University, Bugwood.org
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Fruit(s)
Ohio State Weed Lab , The Ohio State University, Bugwood.org
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