Silphium asteriscus L.

Locations ofSilphium asteriscus L. in Virginia

Show image without county labels

Detail

Family
Asteraceae
Botanical Name
Silphium asteriscus L.
Common Name
Rosin Weed
Synonym(s)
Flora of Virginia Name/Status
Silphium asteriscus L.
Comments
The map of Silphium asteriscus sensu lato is provided here to show the overall distribution of the species. Three varieties (var. asteriscus, var. latifolium, and var. trifoliatum) are recognized and maps of their distribution are also provided. However, the Flora of Virginia has not ventured beyond species level because of the messy intergradation that often blurs the boundaries between the segregates. Vars. latifolium and trifoliatum, in particular, are differentiated by leaf shape (ovate vs. lanceolate) and leaf arrangement - opposite in var. latifolium and whorled in var. trifoliatum. Populations, and even individual plants, that contain leaf conditions of both vars. are frequent and make these two taxa seem questionably distinct, at least in our region.
Habitat
As a whole, the species inhabits dry-mesic to dry (occasionally mesic) open forests, woodlands, barrens, riverside prairies, clearings, old fields, meadows, and road banks; it is especially common in base-rich soils. The species is frequent in the mountains and Piedmont, infrequent in the Coastal Plain. Habitat details for infraspecific taxa are provided with the varietal maps.
Native Status
Native

To save this map, right-click (control-click for Mac users) on the map and choose "Save Image As...".