Italian thistle is a slender, prickly-stemmed annual or biennial growing 1' to 6' tall with pinnately-cleft leaves that have lobes with spine-tipped teeth.  The alternate leaves are greenish and slightly woolly above and white-tomentose beneath, 4"-5" long, with bases that clasp the stem and extend downwards forming spiny wings.  The discoid flowering heads are about 1/2" wide, sessile or short-peduncled, and in clusters of 2-5 at the stem ends.  The phyllary tips are spreading to ascending, linear-lanceolate, spiny and scabrous, with bases that are covered with wool at the base.  The corollas are rose-purple, and the corolla lobes about three times as long as the tubes.  The fruit is a light tan or buff achene 1/4" long with a pappus of dirty-gray, hairlike bristles up to 3/4" long.  Italian thistle is an occasional weed growing along roads, trails, firebreaks and in pastures and other disturbed areas, blooming from May to July.  It is a native of Europe.

Click here for Latin name derivations: 1) Carduus 2) pycnocephalus.
Pronunciation: KARD-ew-us pik-no-SEF-a-lus.
Click here for Botanical Term Meanings.