Cirsium occidentale (Nutt.) Jepson var. occidentale

Cobweb Thistle
Asteraceae (Sunflower Family)



 

Cobweb thistle is a tall, stout, leafy biennial growing from 2' to 5' tall.  The leaves are alternate, narrow-lanceolate, wavy-margined, pinnately-lobed and spinose, and up to 12" long.  They are densely gray or whitish tomentose, especially beneath, and the upper leaves are reduced in size, sessile, and ± clasping or short-decurrent.  The flowering heads are discoid, solitary on long leafy stems that are somewhat thicker than those of California thistle.  The involucres are large, globose, to 2" in diameter, and densely cobwebby.  The phyllaries are acicular, spreading to ascending, and interconnected by a webbing of fine, whitish tomentum.  There are disk flowers only, purplish-red with corollas to 1-1/4".  The fruit is a brownish achene about 1/4" long. Cobweb thistle inhabits sandy to grassy or brushy locations in coastal strand, coastal sage scrub and chaparral, mostly at fairly low elevations, from cismontane southern California to central California, and blooms from April to July.

Click here for Latin name derivations: 1) Cirsium 2) occidentale.
Pronunciation: SIR-see-um ok-si-den-TAY-lee.
Click here for Botanical Term Meanings.

 







Return to Home Page