Regularity: Regularly occurring
Foodplant / parasite
Golovinomyces cichoracearum parasitises live Carduus tenuiflorus
Foodplant / spot causer
amphigenous colony of Ramularia hyphomycetous anamorph of Ramularia cynarae causes spots on live leaf of Carduus tenuiflorus
Foodplant / feeds on
larva of Terellia serratulae feeds on Carduus tenuiflorus
Molecular Biology and Genetics
Barcode data: Carduus tenuiflorus
Statistics of barcoding coverage: Carduus tenuiflorus
Public Records: 7
Specimens with Barcodes: 7
Species With Barcodes: 1
National NatureServe Conservation Status
Rounded National Status Rank: NNA - Not Applicable
Carduus tenuiflorus, known variously as slender-flower thistle, sheep thistle, shore thistle, slender thistle, winged plumeless thistle, winged slender thistle, and winged thistle) is a species of thistle.
Carduus tenuiflorus is native to western North Africa in: northern Algeria; Morocco; and Tunisa, and much of Europe in: Belgium; France, including Corsica; Ireland; Italy, including Sardinia and Sicily; the Netherlands; Portugal, Spain, including the Baleares (Balearic Islands); and the United Kingdom.
Carduus tenuiflorus may exceed 2 metres (6.6 ft) in height. Its tall stem is ridged with wings and has long spines which may be several centimeters in length. The dull olive-green leaves are lobed and wrinkled and may fold and crease themselves.
The inflorescences may hold up to 20 flower heads which are somewhat rounded, covered in wide, spiny phyllaries, and packed with pale pink to bright purple long-tubed disc florets. This is a tenacious weed of roadsides, fields, and disturbed areas.
- Carduus tenuiflorus was first described and published in Flora Londinensis 2(6): t. 55 (168,169). 1793. GRIN (May 9, 2011). "Carduus tenuiflorus information from NPGS/GRIN". Taxonomy for Plants. National Germplasm Resources Laboratory, Beltsville, Maryland: USDA, ARS, National Genetic Resources Program. Retrieved January 23, 2012.
- Cal-IPC (California Invasisive Plant Council): Carduus tenuiflorus . accessed 4.8.2013
Carduus pycnocephalus and C. tenuiflorus are similar annuals with small, usually tightly clustered heads. The number of heads per capitulescence is usually ultimately greater in C. tenuiflorus, but early season plants of this species often have only a few heads. At the end of the growing season the fruiting heads of C. tenuiflorus are aggregated in dense, subspheric clusters. Stem wings tend to be more pronounced in C. tenuiflorus. Fresh corollas of C. pycnocephalus are rose-purple whereas those of C. tenuiflorus have a more pinkish tinge, but this difference is subtle and not reliable on herbarium material. The phyllaries of C. tenuiflorus are membranous-margined, more or less glabrate, and lack the short, stiff, upwardly appressed trichomes of C. pycnocephalus. All published chromosome counts for Carduus tenuiflorus from both Old and New World material are the same.
The two species sometimes grow in mixed populations and at times appear to intergrade. Hybridization has been reported in Europe (S. W. T. Batra et al. 1981) and is suspected to occur in California. Hybrids between C. pycnocephalus and C. tenuiflorus have been designated Carduus ×theriotii Rouy.
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