The false oranges are a group of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. They include all forbs (flowering plants without a woody stem), grasses and grass-like plants, a vast majority of ...

s in the ''

Citrus ''Citrus'' is a genus of flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, lemons, grapefruits, pomelos, and limes. The genus ''Citrus'' is nati ...

'' genus, within the family,

Rutaceae The Rutaceae is a family, commonly known as the rueRUTACEAE
in BoDD – Botanical Der ...

. They are

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found els ...

to New Caledonia. Though previously viewed as members of ''Citrus'', Swingle moved the false oranges into their own genus, ''Oxanthera''. He placed the genus within the Triphasiinae subtribe of

Citreae Citreae is one of the two tribes of the flowering plant family Rutaceae, subfamily Aurantioideae, the other being Clauseneae. Subtribes and genera Three sub-tribes are included: * Triphasiinae ** '' Luvunga'' Buch.-Ham. ex Wight & Arn. ** ...

based on the similar size of their fruit. However, subsequent

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

analysis showed them to cluster in the Citrinae subtribe within the same clade as Swingle's genus '' Clymenia'' and the

Australian lime Australian limes are species of the plant genus ''Citrus'' that are native to Australia and Papua New Guinea. These species were formerly included in the genera ''Microcitrus'' and ''Eremocitrus''. They have been used as a food source by indigen ...

s, as members of an enlarged monophyletic ''Citrus'', with the suggested relegation of the ''Oxanthera'' taxon as a ''Citrus''

subgenus In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed betw ...

. Bayer observed the presence of prominent pulp vesicles in the false oranges, and that their flowers had three to four times as many

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

s as

petal Petals are modified leaves that surround the reproductive parts of flowers. They are often brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corolla''. Petals are usuall ...

s in their flowers, are both traits similar to other ''Citrus''. The false orange lacks the thorns typical of the ''Citrus'' genus, a difference often seen on islands without endiginous herbivores. Species include:GRIN Species Records of ''Oxanthera''.
Germplasm Resources Information Network (GRIN).
University of California, Riverside. * ''

Citrus oxanthera ''Citrus oxanthera'', synonym ''Oxanthera aurantium'', is a species of plant in the family Rutaceae. Sometimes referred to commonly as the orange-flowered oxanthera, it is endemic to New Caledonia. Taxonomy ''Citrus oxanthera'' has historically ...

'' — orange flower oxanthera * ''

Citrus neocaledonica ''Citrus neocaledonica'', synonym ''Oxanthera neocaledonica'', the large leaf oxanthera, is a species of plant in the family Rutaceae. It is endemic to New Caledonia. Taxonomy ''Citrus neocaledonica'' was originally named as a member of the gen ...

'' — large-leaf oxanthera * ''

Citrus undulata ''Citrus undulata'', synonym ''Oxanthera undulata'', the wavy-leaf oxanthera, is a species of plant in the family Rutaceae. It is endemic to New Caledonia. Taxonomy Originally characterized and named as ''Citrus undulata'' by André Guillaumin ...

'' — wavy-leaf oxanthera * ''

Oxanthera brevipes ''Oxanthera brevipes'' is a species of plant in the family Rutaceae. It is endemic to New Caledonia. It was proposed as a novel species by Benjamin C. Stone based on two specimens, distinguished from other false oranges by a non-articulated p ...

'' (status pending)

References

Aurantioideae Endemic flora of New Caledonia Taxonomy articles created by Polbot {{Rutaceae-stub