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Senecio L.
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 Senecio anonymus Wood (= Senecio smallii Britton) Golden or Southern ragwort |
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Senecio anonymus Wood (= Senecio smallii Britton) Golden or Southern ragwort |
| Discover Life in America | Flora & Fauna | Plants | Asteraceae | Senecio |
Senecio is the largest of 1,300 genera in the family Asteraceae (sunflowers), which includes 21,000 described species (Hickman 1993). The genus includes ragworts, groundsels, butterweed, and a total of approximately 1,200 species worldwide (Porcher 1995). While the genus includes some shrubs, species of Senecio are either herbaceous perennials or winter annuals in the southeastern United States (Radford et al. 1968). A common and conspicuous perennial is Southern ragwort, Senecio anonymus, which is easily seen flowering along roadsides from April to June. Butterweed, Senacio glabellus, is an annual and reputed to be poisonous when eaten (Duncan & Foote 1975), as are other species of Senecio (Bain 1991; Clawson 1933; Kingsbury 1964). Because of their toxicity to livestock, some species are noxious weeds. Biological control using flea beetles has had considerable success at controlling Tansy Ragwort, Senecio jacobaea, a species introduced from Europe to North America that has become a problem on rangeland, particularly in the Pacific Northwest.
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| Discover Life in America | Flora & Fauna | Plants | Asteraceae | Senecio |
| Senecio aureus L. | - Golden ragwort |
| Senecio anonymus Wood | - Yellow or Southern ragwort |
| Senecio glabellus Poiret | - Butterweed |
| Senecio millefolium Torrey & Gray | - Divided-leaf ragwort, Blue Ridge golden ragwort |
| Senecio obovatus Muhl. ex Willd. | - Spatulate-leaved ragwort |
| Senecio pauperculus Michaux | |
| Senecio robbinsii Oakes ex Rusby | |
| Senecio rugelia Gray | |
| Senecio tomentosus Michaux | - Woolly ragwort |
| Senecio vulgaris L. | - Common groundsel |
This list is based on Radford et al. (1968), who recognize 10 species of Senecio in the Carolinas. S. anonymus updates S. smallii.
| Discover Life in America | Flora & Fauna | Plants | Asteraceae | Senecio |
Senecio has a worldwide distribution. Some species are widespread, others rare and localized. Some of the more widespread ones, such as Tansy ragwort, Senecio jacobaea, and Common groundsel, Senecio vulgaris, are exotic pests, having been introduced into rangeland in North America, Australia and elsewhere where they cause consider ecological and economic disruption. Other species are rare and face possible extinction. In the southeastern United States, for example, Senecio millefolium (Ragwort), Senecio plattensis (Prairie ragwort), and Senecio schweinitzianus (Robbin squaw-weed) are three such species that are either listed or under consideration for protection by state and federal authorities.
In Great Smoky Mountains National Park, three species have been documented (GSMNP checklists, as of May, 1999): Yellow ragwort (Senecio anonymus), Golden ragwort (Senecio aureus), and Spatulate-leaved ragwort (Senecio obovatus). Yellow ragwort is the most frequently encountered and occurs at both low (850 - 2,500ft) to mid (2,500 - 4,500ft) elevations. The other two species grow at low elevations, Golden ragwort being well distributed but nowhere abundant, and Spatulate-leaved ragwort growing at scattered sites throughout the park.
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References
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