You selected Houstonia purpurea var. longifolia (Gaertn.) A.Gray. This is a synonym for:

Accepted scientific name:
Houstonia longifolia Gaertn. (accepted name) 1 literature reference for Houstonia longifolia Gaertn.
Synonyms:
Chamisme longifolia (Gaertn.) Nieuwl. (synonym) 1 literature reference for Chamisme longifolia (Gaertn.) Nieuwl.
Hedyotis longifolia (Gaertn.) Hook. (synonym) 1 literature reference for Hedyotis longifolia (Gaertn.) Hook.
Hedyotis purpurea var. longifolia (Gaertn.) Fosberg (synonym) 1 literature reference for Hedyotis purpurea var. longifolia (Gaertn.) Fosberg
Houstonia purpurea var. longifolia (Gaertn.) A.Gray (synonym) 1 literature reference for Houstonia purpurea var. longifolia (Gaertn.) A.Gray
Oldenlandia purpurea var. longifolia (Gaertn.) A.Gray (synonym) 1 literature reference for Oldenlandia purpurea var. longifolia (Gaertn.) A.Gray
Infraspecific taxon: Houstonia longifolia var. longifolia
Houstonia longifolia var. tenuifolia (Nutt.) Alph.Wood
Common names: -
Classification:
Plantae
Phylum Magnoliophyta
Class Magnoliopsida
Order Rubiales
Family Rubiaceae
Genus Houstonia
Distribution: Canada, E. & NC. U.S.A.
Additional data: -
Source database: World Checklist of Selected Plant Families, 27 Nov 2009
Latest taxonomic scrutiny: Govaerts R., 11-Nov-2003
Online resource: http://apps.kew.org/wcsp/namedetail.do?accepted_id=100361&repSynonym_id=-9998&name_id=100361&status=true
CoL taxon LSID: urn:lsid:catalogueoflife.org:taxon:f0e5347a-29c1-102b-9a4a-00304854f820:ac2010