Silphium asteriscus L.

Locations ofSilphium asteriscus L. in Virginia

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Botanical Name
Silphium asteriscus L.
Common Name
Rosin Weed
Flora of Virginia Name/Status
Silphium asteriscus L.
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.
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

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