Taxon  Report   1853 
Centaurea solstitialis  L.
Barnaby's thistle,  Yellow star thistle
Centaurea solstitialis
© 2008 Luigi Rignanese
Click on a photo to see it bigger.
Centaurea solstitialis
© 2014 Robert F Norris
Centaurea solstitialis
© 2008 Thomas Stoughton
Centaurea solstitialis, a dicot, is an annual herb that is not native to California; it was introduced from elsewhere and naturalized in the wild.
It is an invasive plant. The California Invasive Plant Council classifies its potential impact on native ecosystems as high (plant profile / CalWeedMapper).

Interactive Distribution Map

Observation Hotline
(observation details + photos)

point, line, or polygon

one or more occurrences
within a 7.5-minute quadrangle

Plant Characteristics
and Associations

Bloom Period
Centaurea solstitialis
© 2004 Carol W. Witham
Genus: Centaurea
weed, characteristic of disturbed places
Habitat: disturbed [Walker]
Distribution by County 

Add an Observation of  Centaurea solstitialis

Name Status:
Accepted by TJM2 + PLANTS + JM93
Alternate Names:
(according to)

PLANTS: Leucantha solstitialis
More information about  Centaurea solstitialis
Photos on CalPhotos / Google Images
Photos and ID tips from

FEIS: DISTRIBUTION AND OCCURRENCE:  "It is likely that there were multiple introductions of yellow starthistle to the United States ... and that contaminated alfalfa seed (Medicago sativa) was the primary vehicle for these introductions ... . Yellow starthistle seeds were found in adobe bricks from the period between 1824 and 1848 in California (Hendry 1931, ...). The plant was first collected in Oakland, California in 1869 and was most likely introduced from Chile, while introductions from 1899 to 1927 appear to be from Turkestan, Argentina, Italy, France and Spain "

UC Integrated Pest Management:  ... It forms dense infestations and rapidly depletes soil moisture, thus preventing the establishment of other species. It is also poisonous to horses, causing a nervous disorder called “chewing disease” ...

UC Integrated Pest Management Weed Photo Gallery
(profile of this plant as an agricultural weed)

Jepson eFlora

Records from the Consortium of California Herbaria

Original Publication citation (ITIS)


Search the International Plants Names Index

Search (Flora of North America)

website references from Google

Suggested Citation
Calflora: Information on California plants for education, research and conservation,
with data contributed by public and private institutions and individuals, including the Consortium of California Herbaria.
[web application]. 2016. Berkeley, California: The Calflora Database [a non-profit organization].
Available:   (Accessed: Oct 27, 2016).

The information on this page comes from diverse sources. None of the links are sponsored.