S. bona-nox: note that the marginal prickles shown in this illustration, though not always present in this taxon, are diagnostic when present (from Britton and Brown 1913).
	Part of: Thornhill R, Krings A, Lindbo D, Stucky J (2014) Guide to the Vascular Flora of the Savannas and Flatwoods of Shaken Creek Preserve and Vicinity (Pender & Onslow Counties, North Carolina, U.S.A.). Biodiversity Data Journal 2: e1099. https://doi.org/10.3897/BDJ.2.e1099