Vascular Plants of North Carolina

Vascular Plants of North Carolina

Account for Carolina Rosinweed + - Silphium compositum var. compositum Michaux

Members of Asteraceae:

Section 6 » Order Asterales » Family Asteraceae

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Author	Michaux
Distribution	More-or-less throughout the state, but with some gaps, notably the northeastern Outer Coastal Plain and apparently scattered in the Mountains. VA to TN, south to FL and AL.
Abundance	Uncommon to common.
Habitat	Dry to xeric soils of Longleaf Pine-Wiregrass communities, savannas, sandhills, oak-hickory woodlands, glades and barrens, rocky slopes, clearings, and roadsides.
Phenology	Flowering and fruiting late May-September.
Identification	Silphium compositum complex consists of 3 varieties plus S. reniforme, according to Weakley (2018); 2 varieties occur in NC. The growth form of all is very distinctive: a basal rosette of very large (a foot long and 8 inches to a foot wide), stalked, basal leaves that lie on the ground, with a single stem 5-7 feet tall and a widely-branched, open inflorescence of relatively small heads. As in other rosinweeds, the heads are yellow and the involucral bracts are thick-textured and rounded. Var. venosum differs in its broader involucres (1.5-3 cm wide vs. 1-1.5) and longer seeds (8-14 mm vs. 6-9). S. reniforme differs in having unlobed leaves, or with a single lobe on each side.
Taxonomic Comments	Some authors, such as FNA, do not recognize any varieties within S. compositum.
Other Common Name(s)
State Rank	S5
Global Rank	G5T5
State Status
US Status
USACE-agcp
USACE-emp

County Map - click on a county to view source of record.

Photo Gallery

photographer	comments	photo_link	county	obsType
B.A. Sorrie	Richmond Co., same data.		Richmond		Photo_natural
B.A. Sorrie	Sandhills Game Land, longleaf pine-wiregrass N of McKinney Lake. 14 Aug 2011.		Richmond		Photo_natural