Bull thistle is a coarse, erect herbaceous biennial with a stout stem usually branched above the middle, loosely tomentose, and often glandular-hairy.  There is a basal rosette of oblanceolate to elliptic, coarsely-toothed leaves which are either sessile or wing-petioled.  The alternate, green, cauline leaves are long-decurrent, lanceolate, up to 12" long, bristly above and tomentose beneath, and deeply pinnately cleft into spreading, spine-margined lobes.  The main veins on the under surface are prominent. The solitary flower heads are discoid with an ovoid to globose involucre which is covered with numerous, imbricated, spine-tipped, linear phyllaries in 5-10 series, the lowermost of which are almost recurved.  The disk flowers are lavender to purple and well exserted with pappi of many plumose bristles.  The flowering heads are closely subtended by bract-like upper leaves.  Bull thistle is a common and aggressive weed that grows to 4' tall, and is found both in chaparral and in waste and disturbed places throughout Southern California below 6000', blooming from June to September.  It is a native of Europe.

Click here for Latin name derivations: 1) Cirsium 2) vulgare.
Pronunciation: SIR-see-um vul-GARE-ee.
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