Helianthus occidentalis Riddell ssp. occidentalis . Naked-stem Sunflower. Phen: Jul-Oct. Hab: Rocky or sandy flood-scoured riversides, dry hammocks (in FL). Dist: MD and DC west to MN, and south to w. NC, n. GA, Panhandle FL, and TX.

Origin/Endemic status: Native

Taxonomy Comments: Ssp. occidentalis occupies most of the range of the species. Ssp. plantagineus (Torrey & Gray) Shinners occurs in sw. LA, se. TX, and AR. Var. dowellianus Torrey & Gray, of uncertain status (if valid, then usually treated as a variety under ssp. occidentalis), occurs in the Appalachian portion of the range.

Other Comments: The species has been collected only twice in NC, the type collection of H. dowellianus M.A. Curtis, from "near Franklin, Macon Co.", and in 1897, near Asheville, Buncombe County ("sandy bottoms along the French Broad River near Biltmore"). GAHP reports H. occidentalis as a rare species in the state, from "limestone glades and barrens, rocky or cherty soils" (GAHP 2003); it is uncertain what variety is represented.

Synonymy: = Ar, FNA21, K1, K3, K4, NE, NY, Oh3, Va; = Helianthus occidentalis Riddell – G, Il, Mi, RAB, S, Tn, W, WH3; = Helianthus occidentalis Riddell var. occidentalis – Pa; > Helianthus dowellianus M.A.Curtis – WV; < Helianthus occidentalis Riddell – Tx; > Helianthus occidentalis Riddell – WV; > Helianthus occidentalis Riddell var. dowellianus (M.A.Curtis) Torr. & A.Gray – C, F, SE1; > Helianthus occidentalis Riddell var. occidentalis – F

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Wetland Indicator Status:

• Atlantic and Gulf Coastal Plain: FACU (taxonomic split from wetland indicator species)
• Eastern Mountains and Piedmont: UPL (taxonomic split from wetland indicator species)
• Great Plains: FACU (taxonomic split from wetland indicator species)
• Midwest: FACU (taxonomic split from wetland indicator species)
• Northcentral & Northeast: FACU (taxonomic split from wetland indicator species)

Heliophily: 8