- Sonchus arvensis is a perennial herbaceous plant. Stems can reach 4.9 ft. (1.5 m) in height and contain milky sap.
- 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.
- 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.
- 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.
McWilliams, Jack 2004. Sonchus arvensis, Fire Effects Information System, U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory 
Minnesota Department of Natural Resources 
University of California, Jepson Flora Project 
Flora of North America, www.eFloras.org 
USDA NRCS PLANTS 
USDA ARS GRIN 
Images from Bugwood.org