Ambrosia psilostachya A.P. de Candolle. Perennial Ragweed. Phen: Jul-Nov. Hab: Calcareous prairies and disturbed areas; in loamy sandy soil of flats and slight depressions in periodically burned longleaf pine uplands; also in disturbed areas. Dist: MI west to MT, south to LA and NM; also scattered along eastern seaboard states (ME, NH, NY, NC, SC, GA, FL, VA), where perhaps some of the distribution is adventive. Apparently first collected in VA in 2000.

Origin/Endemic status: Native

Taxonomy Comments: The native plants of loamy longleaf pine sandhills may be distinct; the name A. rugelii likely applies.

Synonymy: = Ar, C, Fl7, FNA21, G, GrPl, Il, K3, K4, Mi, NcTx, NE, NY, Oh3, Ok, Pa, SE1, Tx, McMillan & Prevost (2022); = Ambrosia pilostachya – WH3, misspelling; = Ambrosia rugelii Rydb. – S; > Ambrosia coronopifolia Torr. & A.Gray – K1; > Ambrosia psilostachya DC. – RAB; > Ambrosia psilostachya DC. var. coronopifolia (Torr. & Gray) Farw. – F; > Ambrosia psilostachya DC. var. psilostachya – F; > Ambrosia rugelii Rydb. – RAB

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Wetland Indicator Status:

• Atlantic and Gulf Coastal Plain: FAC
• Eastern Mountains and Piedmont: FAC
• Great Plains: FACU
• Midwest: FACU
• Northcentral & Northeast: FAC

Heliophily: 8