Azure bluet
- kingdom: Plantae
- phylum: Tracheophyta
- class: Magnoliopsida
- order: Gentianales
- family: Rubiaceae
- genus: Houstonia
- species: Houstonia caerulea
Hampton- Saint Andrews
New Brunswick- Kentville
Nova Scotia- Farnham
- Montréal
- Nicolet
- Pierreville
Quebec
Canada
Göteborg
Västra Götaland
Sweden
Ashville- Auburn
- Northport
- Thomasville
- Tuscaloosa
Alabama- Beltsville
- Berwyn Heights
- Bladensburg
- Brentwood
- Cabin John
- Cheverly
- Chevy Chase
- Chevy Chase Village
- College Park
- Colmar Manor
- Cottage City
- District Heights
- East Riverdale
- Edmonston
- Forest Glen
- Forestville
- Friendship Village
- Glenmont
- Goddard
- Hyattsville
- Kensington
- La Plata
- Langley Park
- Lanham
- Laurel
- Maryland City
- Morningside
- Mount Rainier
- Mountain Lake Park
- New Carrollton
- North Kensington
- North Potomac
- Riverdale Park
- Seabrook
- Silver Spring
- Somerset
- South Kensington
- South Laurel
- Takoma Park
- Travilah
- Wheaton
Maryland- Hadley
Massachusetts- Centre Hall
Pennsylvania- Washington, D. C.
Washington, D.C.- Milwaukee
Wisconsin
United States