common horsegentian
- kingdom: Plantae
- phylum: Tracheophyta
- class: Magnoliopsida
- order: Dipsacales
- family: Caprifoliaceae
- genus: Triosteum
- species: Triosteum perfoliatum
East Haven- East Norwalk
- New Haven
- Norwalk
- Orange
Connecticut- Emporia
Kansas- Brookmont
- Cabin John
- Chesapeake Beach
- North Beach
Maryland- East New York
- Northport
New York- Mount Vernon
- Woodlawn
Virginia- Lake Geneva
- Spooner
Wisconsin
United States