Cirsium horridulum
{{Short description|Species of thistle}}
{{Speciesbox
| image = Bristle Thistle.jpg
| image_caption =
| genus = Cirsium
| species = horridulum
| authority = Michx.
| synonyms_ref = [http://www.theplantlist.org/tpl1.1/record/gcc-105276 The Plant List, Cirsium horridulum Michx. ]
| synonyms = {{collapsible list|bullets = true
|title=Synonymy
|Carduus horridulus Pers.
|Carduus pinetorum Small
|Carduus spinosissimus Walter
|Carduus vittatus Small, syn of var. vittatum
|Cirsium chrismarii (Klatt) Petr.
|Cirsium pinetorum (Small) Small 1913 not Greenm. 1905
|Cirsium vittatum (Small) Small, syn of var. vittatum
|Cnicus chrismarii Klatt
|Cnicus horridulus (Michx.) Pursh
|Cirsium megacanthum Nutt., syn of var. megacanthum
|Carduus smallii (Britton) H.E.Ahles, syn of var. vittatum
|Cirsium smallii Britton, syn of var. vittatum
}}
}}
Cirsium horridulum, called bristly thistle, purple thistle, or yellow thistle is a North American species of plants in the tribe Cardueae within the family Asteraceae. It is an annual or biennial.{{cite web |url=https://plants.usda.gov/core/profile?symbol=ciho2|title= Plants Profile for Cirsium horridulum (yellow thistle) |website= plants.usda.gov |access-date= 16 January 2018 |author=}} The species is native to the eastern and southern United States from New England to Florida, Texas, and Oklahoma as well as to Mexico, Belize, Guatemala, Honduras, and the Bahamas.[http://bonap.net/MapGallery/County/Cirsium%20horridulum.png Biota of North America Program 2014 county distribution map]Davidse, G., M. Sousa-Peña, S. Knapp & F. Chiang Cabrera. 2015. Asteraceae. 5(2): ined. In G. Davidse, M. Sousa Sánchez, S. Knapp & F. Chiang Cabrera (eds.) Flora Mesoamericana Universidad Nacional Autónoma de México, México D.F.Carnevali, G., J. L. Tapia-Muñoz, R. Duno de Stefano & I. M. Ramírez Morillo. 2010. Flora Ilustrada de la Peninsula Yucatán: Listado Florístico 1–326Nelson, C. H. 2008. Cat. Pl. Vasc. Honduras 1–1576. Secretaria de Recursos Naturales y Ambiente, TegucigalpaNash, D. L. 1976. Tribe IX, Cynareae. En: Nash, D.L. & Williams, L.O. (eds), Flora of Guatemala - Part XII. Fieldiana, Bot. 24(12): 423–428, 590
Thomas Nuttall (1786-1859) described var. megacanthum as "one of the most terribly armed plants in the genus."Nuttall quoted in [http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250068186 Flora of North America, Bigspine thistle, Cirsium horridulum Michaux var. megacanthum (Nuttall) D. J. Keil][https://www.biodiversitylibrary.org/page/36318142#page/443/mode/1up Nuttall, Thomas 1841. Transactions of the American Philosophical Society, new series 7: 421] as Cirsium megacanthum
File:Early Flowering Stage Cirsium horridulum.jpg
Cirsium horridulum is a biennial herb up to {{convert|250|cm|-1}} tall, with a large taproot and fleshy side roots that sometimes sprout new shoots. Leaves are up to {{convert|40|cm}} long with thick, sharp spines along the edges. There are usually several flower heads, also with sharp spines, each head with disc florets but no ray florets. Flower color varies from one plant to the next: white, yellow, pink, red or purple.[http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250066376 Flora of North America, Bristly or horrid or yellow or bull thistle, Cirsium horridulum Michaux, Fl. Bor.-Amer. 2: 90. 1803. ]
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- Cirsium horridulum var. horridulum - from Maine to Guatemala
- Cirsium horridulum var. megacanthum (Nutt.) D.J.Keil - from the Florida Panhandle to Texas and Oklahoma
- Cirsium horridulum var. vittatum (Small) R.W.Long - from North Carolina to Louisiana
Conservation status in the United States
It is endangered in Connecticut,[http://www.ct.gov/deep/lib/deep/wildlife/pdf_files/nongame/ets15.pdf "Connecticut's Endangered, Threatened and Special Concern Species 2015"]. State of Connecticut Department of Energy and Environmental Protection Bureau of Natural Resources. Retrieved 12 January 2018. (Note: This list is newer than the one used by plants.usda.gov and is more up-to-date.) New Hampshire, and Pennsylvania. It is listed as threatened in Rhode Island.{{cite web |url=https://plants.usda.gov/core/profile?symbol=ciho2|title= Plants Profile for Cirsium horridulum (yellow thistle) |website= plants.usda.gov |access-date= 16 January 2018 |author=}}
As a noxious weed
Native American [[ethnobotany]]
The Houma people make an infusion of the leaves and root of the plant in whiskey. They use it as both as an astringent, and drink it to clear phlegm from lungs and throat. They also eat the tender, white hearts of the plant raw.Speck, Frank G., 1941, "A List of Plant Curatives Obtained From the Houma Indians of Louisiana", Primitive Man 14:49-75, page 57 The Seminole use the spines of the plant as darts for their blowguns.Sturtevant, William, 1954, The Mikasuki Seminole: Medical Beliefs and Practices, Yale University, PhD Thesis, page 507
Ecology
It is a larval host to the little metalmark and the painted lady butterflies.The Xerces Society (2016), Gardening for Butterflies: How You Can Attract and Protect Beautiful, Beneficial Insects, Timber Press. Its flowers are popular for their nectar and pollen with butterflies and bumble bees.