Conserved and rejected plant names, suppressed publications, and binding nomenclature decisions: proposals and disposals

by Dan H. Nicolson (revised in 2015 by John H. Wiersema)

For additional background, history, and analysis see the following publications:
  • Nicolson, D.H. 2000. A new online bibliographic database of proposals for conservation and rejection of botanical names. Taxon 49: 549-554.
  • Wiersema, J.H., McNeill, J., Turland, N.J., Orli, S.S., & Wagner, W.L. 2015. The foundation of the Melbourne Code Appendices: announcing a new paradigm for tracking nomenclatural decisions. Taxon 64: 1021-1027.


  • Introduction
  • Implicitly conserved and rejected names
  • Headings:
  • Props / Cons. / Rej. / Suppr. / Descr. / Parahom. / Group / Subgroup / Action / Author / Place / Synopsis / Group Comm. / Gen. Comm. / Congr. Proc. / Comm. & Rev. / Code / Code Entries

    Introduction: It is not widely known but there is a story behind almost every name listed in the Appendices of the International Code of Nomenclature (ICN), which now bulk far larger than the Code itself. Indeed there is a story behind many names not listed, i.e. that were proposed and were not approved. It behooves anyone interested in a particular name to check this database to see if it has been considered for conservation and/or rejection. The database aims to document the steps that proposals go through so that one can trace the history of every proposed name. As a matter of historical interest, an index to conserved and rejected names was published by Rickett & Stafleu (Taxon 10: 178-193. 1961).

    Implicitly conserved and rejected names: Every name explicitly proposed for conservation or rejection is accounted for. This is simple when dealing with family and generic names, i.e. Appendices II (Family Names), III (Generic and Infrageneric Names). However, difficulties begin when conserving and/or rejecting species names. This is because one usually proposes to conserve or reject a basionym, not the combination(s) based on it. Appendices IV (Conserved and Rejected Species and Infraspecific Names) and V (Suppressed Names) both explicitly provide that whatever pertains (conservation or rejection) to a listed basionym, may also pertain to any combination based on it, listed or not, provided that such a combination with a conserved basionym is not an illegitimate later homonym, which itself must be explicitly conserved. These implicitly conserved or rejected combinations are confusing but perhaps two examples will clarify:

    1. Cactus cruciformis Vell. 1829 is explicitly conserved (Appendix IV) against explicitly rejected (1) Cereus squamulosus Salm-Dyck ex DC. 1828, (2) Cereus tenuispinus Haw. 1827, (3) Cereus myosurus Salm-Dyck ex DC. 1828, and (4) Cereus tenuis DC. 1828. This means that combinations based on conserved Cactus cruciformis Vell., such as Lepismium cruciforme (Vell.) Miq. 1838, are implicitly conserved over any combination based on any of the explicitly rejected names. The opposite also pertains. Such combinations would not, however, be conserved over any earlier homonyms.
    2. Magnolia tomentosa Thunb. 1794 (Thymelaeaceae, not Magnoliaceae) is explicitly rejected (Appendix V). This means that a combination based on it, Edgeworthia tomentosa (Thunb.) Nakai 1919, is implicitly rejected against any name it might threaten, such as Edgeworthia papyrifera Siebold & Zucc. 1846 or E. chrysantha Lindl. 1846.

    All implicitly conserved names cross-referenced in the Code's Appendix IV (e.g. Lepismium cruciforme (Vell.) Miq.) and the implicitly rejected names cross-referenced in Appendix V (e.g. Edgeworthia tomentosa (Thunb.) Nakai) have been added to the database. This means that if you are interested in whether or not there is a conservation or rejection proposal concerning Edgeworthia, you should use the generic name to query the scientific name field. You will find Edgeworthia tomentosa listed as a rejected name, although the original proposal was to explicitly reject only its basionym, Magnolia tomentosa.

    Headings: There are 18 often abbreviated headings in a proposals/requests report, each often using abbreviations in the content:

    1. Proposal/Request No. = Proposal/request number. Although proposals began in 1892, the assignment of a continuing series of numbers did not begin until 1955, and those for requests not until 2013. Thus many proposals/requests appear without numbers.
    2. Cons. = Name(s) proposed for conservation under Art. 14.
    3. Rej. = Name(s) proposed for rejection, whether against a conserved name (Art. 14) or for outright rejection (nom. utique rej., Art. 56).
    4. Suppr. = Publication proposed for suppression under Art. 34.
    5. Descr. = Request for a binding decision on descriptive statement under Art. 38.4.
    6. Parahom. = Request for a binding decision on confusingly similar names (parahomonymy, Art. 53.5).
    7. Group = Proposals/requests can be sorted into one of 6 taxonomic groups: Spermatophyta (Spermatoph.), Pteridophyta (Pteridoph.), Bryophyta (Bryoph.), Fungi (Fungi), Algae (Algae), and Fossils (Foss.).
    8. Subgroup = In Appendix III, proposals involving Spermatophyta (2), Bryophyta (2), and Algae (11) are sorted into the number of subgroups indicated.
    9. Action = The nomenclatural action sought or proposed. The codes used mostly involve two parts:
      1. the initial capital letter: A=amend an existing conservation entry, C=conserve a name, D=seeks a binding decision on a descriptive statement, O=suppress a work, P=seeks a binding decision on parahomonymy, R=reject a name outright
      2. in lower case, the rank of the name involved, if applicable: f=family, g=genus, se=section, sf=subfamily, sg=subgenus, sp=species, ssp=subspecies, st=supertribe, t=tribe, v=variety.
    10. Author = The author(s) of the proposal/request.
    11. Place = Where the proposal/request was published.
    12. Synopsis = Synopsis of Proposals to a particular Congress where this proposal was cited.
    13. Group Comm. = Place where the permanent nomenclature Committee of the Group (see #7 above) made its recommendation on the proposal/request, expressed as: a) + = recommended for the proposal, or decided in favor of valid publication or confusability (more than 50% or, recently, more than 60% in favor), b) - = recommended against the proposal, or decided against valid publication or confusability (more than 50% opposed or not voting or, recently, more than 60% opposed), c) no recommendation or decision, recently, 60% or more neither opposed nor in favor, or d) w = the proposal/request was withdrawn. The absence of a recommendation can be an invitation to the General Committee to see if they can vote decisively.
    14. Gen. Comm. = Citation where the General Committee made its recommendation on the proposal/request. The mathematical signs used (+ and -) are explained above (under 13). Under current Codes, i.e., Art. 14.16, 34.2, and 56.4, when a proposal for conservation (Art. 14) or rejection (Art. 56) of a name, or for suppression of a publication (Art. 34), has been approved by the General Committee after study by the Committee for the taxonomic group concerned, retention (or rejection) of that name or suppression of that publication is authorized subject to the decision of a later International Botanical Congress.
    15. Congr. Proc. = Citation in the Proceedings of the Congress that authorized inserting the name in the Code. Authorization is a two-step process: (1) a statement that the actions of the General Committee are ratified by the Nomenclature Section, and (2) the actions of the Nomenclature Section are ratified by the Congress itself. The citation should be of the latter but the former may have been cited sometimes.
    16. Comm. & Rev. = Comments and revisions. Comments, pro or con, were sometimes made on a proposal. Revisions are published emendations to already listed names, e.g. early generic conservations lacked citation of generic types, added in revisions published in Taxon. The basis for other unpublished editorial revisions to entries are also provided here.
    17. Code = The Codes where the action involving the name(s) or publication have appeared. Sometimes names or publications that were only approved by the appropriate Group Committee were put in a Code with an asterisk (*): "Conservation/rejection of a name or suppression of a publication still subject to approval by the General Committee and/or the next International Botanical Congress." The * entry for that Code was cited and, if all went well, followed with the citation of the first Code where it appeared without an asterisk or, as sometimes happened, with a note that it had been dropped, i.e. disappeared.
    18. Code Entries = If the proposal/request was approved or decided by an International Botanical Congress, the entries from the Melbourne Code Appendices (Regnum Veg. 157. 2015) of all names or publications associated with the proposal/request are provided.


    last revised 10 July 2015