Perennial Sowthistle

Perennial Sowthistle, Sonchus arvensis

Family: Asteraceae; Sunflower Family

Vegetative Characteristics:

Seedling: hypocotyl glabrous; cotyledons spatulate, pale green; first true leaves with glaucous underside and spine-tipped edges

Stems: erect, stout, large, hollow, milky sap, glaucous, gland-tipped trichomes on upper stem and peduncles.

Leaves: alternate, shiny green, sinuate pinnatifid with 2-5 lobes, spiny edges, base sessile and clasping.

Reproductive Characteristics: 

Inflorescences: corymb-like terminal clusters, yellow to golden; heads 14.0-22.0 mm tall, 3.0-5.0 cm wide

Fruits: achene, dark reddish brown, oblong, ribbed; pappus 10.0-14.0 mm long, easily dislodged

Special Identifying Features

⇒ erect perennial; deep taproot; stem hollow and containing milky sap, horizontal branches producing new plants; leaf base clasping; flowers yellow in daisy-like heads