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Similarly spelled names/epithets, confusable (orthographic variants),
correctable errors, or not?

There is a grey area between names (family, generic, binomial, even trinomial) that are spelled exactly the same (outright homonyms) and those that are spelled completely differently. The grey area involves names that are so similar that they might be confused or considered to be orthographic variants. Complexities include the possibility that an orthographic error might be correctible.
The original idea for this database was that it might reveal patterns for decisions on confusability in the column “ Comments and Revisions”

Provisions from the current 2006 (Vienna) Code:

Note Footnote on p. 1: * … a prefixed asterisk denotes a “voted Example”, accepted by a Congress in order to legislate nomenclatural practice when the corresponding Article of the Code is open to divergent interpretation or does not adequately cover the matter.”

Art. 53.3 (p. 96) “When two or more generic or specific names based on different types are so similar that they are likely to be confused (because they are applied to related taxa or for any other reason) they are to be treated as homonyms (see also Art. 61.5). If established practice has been to treat two similar names as homonyms, this practice is to be continued if it is in the interests of nomencaltural stability.”

Art. 53.3 *Ex. 6 (p. 96) lists 4 similarly spelled generic names treated as homonyms. *Ex. 7 lists three similarly spelled generic names (named for the same person) that are treated as homonyms. *Ex. 8 lists two similarly spelled dinoflagellate generic names to be considered homonyms. *Ex. 9 lists 11 sets of species epithets likely to be confused if combined under the same generic or specific name. *Ex. 10 lists 12 similarly spelled names not likely to be confused. Ex. 11 lists 4 pairs of generic names conserved against the earlier similarly spelled name treated as a homonym. Ex. 12 lists an example of two generic names long treated as homonymys.

Art. 53.4 (p. 96-97) deals with confusably similar subdivisions of genera and infraspecific names with 3 examples (Ex. 13-15), plus an example (Ex. 16) of similar infrageneric names in different genera.

Art. 53.5 (p. 97) says “When it is doubtful whether names or their epithets are sufficiently alike to be confused, a request for a decision may be submitted to the General Committee (see Div. III), which will refer it for examination to the committes(s) for the appropriate group(s).” Most (but not all) questions have been informally referred to the Vascular Plant Committee, which reports its decisions in published committee reports which are normally ratified by the General Committee.

Ex. 17 (p. 97) lists three names ruled as likely to be confused and Ex. 18 lists five names ruled as not likely to be confused (all are in the database).

About 100 decisions have been made but few are listed in the Code. It seemed that there was a need to see if a database could be generated that would record the cases that have actually been discussed by a Permanent Committee or ratified at a Congress. It would be especially useful if a brief statement of the “why” of the decision and not merely “what” was decided. This database is my first try.

I would be delighted to have comments, whether pointing out sins of omission or commission and, more particularly, how to make it clearer and easier to use.
Dan H. Nicolson (17 Oct 2007)

Mechanics (using the site)

1. The first column “Prop.” Deals with whether it is a generic or species proposal.

2. The second column “Confusable?” is the most recently published name followed by its date, i.e. the question is whether or not it is confusable with the following“earlier” name in the 3rd column. If a species name is involved, the epithet comes first, followed by the date and the generic name.

3. The third column “Earlier” is the earlier name, in the same format as the later name of the 2nd column.

4. The 4th column “Group” indicates which Taxonomic Committee was involved, Spermatophyta, Bryophyta, Algae, Pteridophyta, etc.

5. The 5th column “Act” is a leftover from another database and may be dropped. Although all should be “cfn?” = Are they confusable?, I include one formal request for an opinion on legitimacy called here “legit?”

6. The 6th column “Author” reports who, if known, asked for an opinion.

7. The 7th column “Where”. There are a few (early) cases in which a request for an opinion was actually published but the bulk of them are simply submitted to a Taxonomic Committee and nothing appears in print until that Committee reports its conclusion.

8. The 8th column “Sp. Comm.” is where the Taxonomic Committee published its opinion.

9. The 9th column “Gen. Comm.” is where the General Committee published its decision (usually acceptance) of the Taxonomic Committee’s report (sometimes with futher discussion).

10. The 10th column “Congr. Proc.” is where a Congress ratifies the actions of the General Committee in the Proceedings of that Congress. Unless the General Committee made a decision, this will be blank.

11. The 11th column “Code” will have no entry unless the example is added to the Code.

12. The 12th column “Comm.&Rev.”, i.e. Comments and Review is where I attempt (trying not to introduce my biases) to briefly give a rationale for the decision.



The 1906 (Vienna) and 1910 (Brussels) Codes stated (Art. 57) that generic names differing only in the termination are to be regarded as distinct (e.g. Peponia and Peponium). This was associated with Recommendation XXXI which said “where a close approach [in spelling] is a source of error (ex.: Astrostemma and Asterostemma in ... the ... same family, Asclepiadaceae, ... Pleuripetalum and Pleuropetalum ... Orchidaceae, only one, the older ... should be kept ...” The latter provision was the first approach to the problem, basically saying that the later of two confusably similar generic names in the same family should be replaced.

In the 1936 (Cambridge) Code the confusability area was dramatically escalated in Art. 70 which stated that the one can correct “typographic ... or ... unintentional orthographic error” .... Generic names differing by the termination must be regarded as distinct but “This does not apply to mere orthographic variants of the same name.”

Art. 70 Note 3 said “... the essential consideration is whether they may be confused with one another or not: if there is serious risk of confusion they should be treated as orthographic variants.” Note 3 added “Doubtful cases should be referred to the Executive Committee” [equivalent to the the today’s General Committee].

It went on with [1] 8 “Examples of retention of original spelling” [not to be corrected], [2] 5 “Examples of typographic errors” [to be corrected], [3] 5 “Examples of unintentional orthographic errors” [to be corrected], [4] 10 “Examples of [similar but] different names” [to stand], [5] 1 “Examples of [two similar but] different specific epithets [to stand] and [6] 6 groups of generic names and 9 groups of species epithets as “Examples of orthographic variants” [to be replaced].

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