Perennial sowthistle (Sonchus arvensis L.)
Perennial sowthistle stems are erect, stout, smooth, and unbranched except at the top. The clasping leaves are alternate and light green, and slightly toothed. Perennial sowthistle can grow anywhere from 4 to 6 feet tall, reproducing by seeds and horizontal roots. The flowers are large and yellow, resembling a dandelion.