|photo by Gil Nelson|
|Division:||Magnoliophyta - Flowering plants|
|Class:||Magnoliopsida – Dicotyledons|
|Family:||Asteraceae ⁄ Compositae|
| Cirsium horridulum|
|Natural range of Cirsium horridulum from USDA NRCS Plants Database.|
Common name: Yellow thistle
There are three varieties: horridulum, magacanthum, and vittatum. Var. horridulum is the only variety with yellow flowers, but it may also have red and purple flowers. 
C. horridulum is found in all the eastern coastal states from Maine to Texas, Tennessee, Arkansas, and Oklahoma.  The varieties may have differing ranges: variety C. horridulum is found throughout the species range, except Oklahoma and Arkansas, variety C. megacanthum is found only in the lower Piedmont and coastal plain, and the variety C. vittatum is isolated to the coastal plain. 
It has been found in pine-wiregrass woodlands, savannahs, pine-scrub oak woodlands, juniper-pine-palm woodlands, longleaf pine-turkey oak barrens, pine hills, cabbage palm hammocks, and along streams and marshes. This species has also been observed in human disturbed habitats such as roadsides, weedy fields, waste grounds, ligand fields, flat spoil areas, shallow watered ditches, pine plantations, and frequently mowed areas. Takes to the moister soil below longleaf pine-scrub oak forested sand hills and occurs in open light conditions in loamy sand or peat, loose sand, and drying loamy sand. Usually inhabits moist open areas between either drier or wetter conditions and may be present in well-drained uplands and limestone substrate.  Associated species include Pinus palustris, Quercus laevis, Melanthera, Eleocharis, Juncus, Xyris, and others. 
This species has been observed flowering from March to October and fruiting from March through November.  The varieties may flower at different times: variety C. horridulum flowers April to June and September with peak inflorescence in April, variety C. megacanthum flowers March to June and variety C. vittatum flowers from February to August.  Kevin Robertson has observed this species flower within three months of burning. KMR The variety C. horridulum has produced natural hybrids with C. pumilum var. pumilum. 
This species is able to grow in burned old fields.
The following Hymenoptera families and species were observed visiting flowers of Cirsium horridulum at Archbold Biological Station. 
Apidae: Apis mellifera
Halictidae: Augochlorella gratiosa, Halictus poeyi, Lasioglossum nymphalis, L. pectoralis
Megachilidae: Lithurgus gibbosus, Megachile brevis pseudobrevis
Use by animals
This species is the larval host to the little metalmark (Calephelis virginiensis) and painted lady (Vanessa cardui) butterflies. 
Diseases and parasites
The leaf epidermis is surrounded by an internal and external cuticle, that reduces the likelihood of a pathogen entering the plan. 
Conservation and management
Cultivation and restoration
Members of the Seminole Tribe have been said to use parts of this plant to make blowgun darts.
References and notes
- []Encyclopedia of Life. Accessed: April 14, 2016
- Florida State University Robert K. Godfrey Herbarium database. URL: http://herbarium.bio.fsu.edu. Last accessed: June 2014. Collectors: L. C. Anderson, G. R. Cooley, J. R. Eaton, R. K. Godfrey, E. Keppner, L. Keppner, R. Kral, H. Kurz, K. MacClendon, K. M. Meyer, K. Patel, P. L. Redfearn Jr., W. R. Stimson, A. Townesmith, L. B. Trott, K. L. Tyson, and C. E. Wood Jr. States and Counties: Florida: Bay, Calhoun, Dade, Dixie, Escambia, Franklin, Gadsden, Jackson, Jefferson, Leon, Levy, Liberty, Marion, Monroe, Pasco, Polk, Taylor, Wakulla, and Washington. Georgia: Grady and Thomas.
- []U.S. Wildflowers. Accessed: April 14, 2016
- Nelson, G. PanFlora: Plant data for the eastern United States with emphasis on the Southeastern Coastal Plains, Florida, and the Florida Panhandle. www.gilnelson.com/PanFlora/ Accessed: 7 DEC 2016
- Kirkman, L. Katherine. Unpublished database of seed dispersal mode of plants found in Coastal Plain longleaf pine-grasslands of the Jones Ecological Research Center, Georgia.
- Deyrup, M.A. and N.D. 2015. Database of observations of Hymenoptera visitations to flowers of plants on Archbold Biological Station, Florida, USA.
- []Florida Native Plant Society. Accessed: April 14, 2016
- Pesacreta, T. C. and K. H. Hasenstein (1999). "The Internal Cuticle of Cirsium horridulum (Asteraceae) Leaves." American Journal of Botany 86(7): 923-928.