Cirsium horridulum
| Cirsium horridulum | |
|---|---|
| Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Asterids |
| Order: | Asterales |
| Family: | Asteraceae |
| Genus: | Cirsium |
| Species: | C. horridulum |
| Binomial name | |
| Cirsium horridulum | |
| Synonyms | |
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Synonymy
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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. 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.
Thomas Nuttall (1786-1859) described var. megacanthum as "one of the most terribly armed plants in the genus."
Cirsium horridulum is a biennial herb up to 250 centimetres (100 in) tall, with a large taproot and fleshy side roots that sometimes sprout new shoots. Leaves are up to 40 centimetres (16 in) long with thick, sharp spines along the edges. There are usually several flower heads, also with sharp spines, Luma apiculata each head with disc florets but no ray florets. Flower color varies from one plant to the next: white, yellow, pink, red or purple.
- Varieties
- 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