The WFO Plant List recognises 29 taxon ranks. Each rank has a standard name that is used in the data and software code. It has a standard abbreviation that could be used in export. These follows Recommendation 5A of the ICNAFP where applicable. Ranks are often represented with different spellings or abbreviations and these are stored in an "Also Known As" field as they are discovered. These variant representations are used during matching and in import scripts. Finally ranks are used to control where a name can be placed in the taxonomy. Each rank has a list of the permitted ranks that its direct child taxa may have. We expect to grow the AKA list but not to add new ranks.

Level Name (internal) Abbreviation (standard) Plural Also Known As Permitted Children
0codeICNCodekingdom; phylum
1kingdomKing.Kingdomssubkingdom; phylum
2subkingdomsubking.Subkingdomsphylum; class; order; family; superorder
3phylumphylumPhylaclass; order; family; superorder
4classclassClassessubclass; order; family; superorder
5subclasssubclass.Subclassesorder; family; superorder
7orderord.Orderssuborder; family
9familyfam.Familiessupertribe; subfamily; tribe; genus
10subfamilysubfam.Subfamiliessupertribe; tribe; genus
12tribetr.Tribestrib.subtribe; genus
13subtribesubtr.Subtribessubtrib.; subtribgenus
14genusgen.Generasubgenus; section; series; species
15subgenussubg.Subgenerasubgen.section; series; species
16sectionsect.Sectionssect; nothosect.subsection; series; species
17subsectionsubsect.Subsectionsseries; species
18seriesser.Seriessubseries; species
20speciessp.Speciesnothospecies; spec.subspecies; variety; form; prole; lusus
21subspeciessubsp.Subspeciesnothosubspecies; nothosubsp.; subsp.; subsp; ssp; ssp.; subspec.variety; form; prole; lusus
22proleprol.Prolesrace; proles
23varietyvar.Varietiesnothovar.; var.; varsubvariety; form; prole; lusus
25formf.Formsforma; fsubform
27lususlus.Lususlus; lusus naturae