BugwoodWiki Article

Italian plumeless thistle
Carduus pycnocephalus L.


Carduus pycnocephalus is an annual or sometimes biennial plant. It can grow from 1-4 ft. (0.3-1.2 m) tall.
The stems have spiny wings. Leaves deeply cut into 2 to 5 pairs of lobes, have white spots and undersurface slightly woolly.
The flowers range from purplish to pinkish, are borne in cylindrical heads either solitary or in clusters of more than 5. The bracts hairy. It blooms from May to June.
Fruits from outer part of flower head are gray in color and inner portion are yellowish to tan.
Ecological Threat
Carduus pycnocephalus is native to southern Europe. It infests roadsides and waste areas, and has become a major problem on hill pasture land in Douglas County, Oregon. Once established, it spreads rapidly and forms dense stands which displace more desirable vegetation and exclude livestock.

General Description:

Carduus pycnocephalus, a member of the Thistle tribe of the Composite family, is an erect winter annual herb 3-18 dm tall.

Diagnostic Characteristics:

Carduus pycnocephalus can be distinguished from other thistle species by its relatively small and few terminal flowerheads and narrow phyllaries with copious tiny, firm, forward-pointing hairs, especially on the midrib (Hitchcock and Cronquist 1973).


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EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org

EDDMapS Distribution

State Invasive List - This map identifies those states that list this species on their invasive species list. For more information, visit Invasive.org

State Invasives List

Taxonomic Rank

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Subclass: Asteridae
Order: Asterales
Family: Asteraceae
Genus: Carduus

Other System Links

Plants: CAPY2
Bayer: CRUPY
GRIN: 316603
ITIS: 35788

Synonyms and Other Names

Other Common Names:
compact-headed thistle, Italian thistle


Category: Forbs/Herbs