Longleaf summer bluet
- kingdom: Plantae
- phylum: Tracheophyta
- class: Magnoliopsida
- order: Gentianales
- family: Rubiaceae
- genus: Houstonia
- species: Houstonia longifolia
Auburn- Cullman
- Northport
- Tuscaloosa
Alabama- Ledyard Center
Connecticut- Manhattan
Illinois- Brookmont
- Brunswick
- Cabin John
- Clarksburg
- Point of Rocks
Maryland- Great Falls
- Leesburg
- Wolf Trap
Virginia- Washington, D. C.
Washington, D.C.
United States