PREFACE
 

This new edition of the International code of botanical nomenclature, like its
immediate predecessor, is in English only (British rather than American Eng-
lish, in cases of discrepancy). French, German, and Japanese editions of the
text of the Berlin Code were produced separately and it is anticipated that at
least French and German editions of the Tokyo Code will be prepared.

The Tokyo Code, is, however, significantly different from the Berlin Code.
There are two reasons for this difference: one relates to the arrangement of the
book and other technical matters, the other to its content.

Considering arrangement first, the Tokyo Congress agreed to delete the major
part of Chapter V dealing with “Retention, choice, and rejection of names and
epithets”, transferring such material as was not already covered elsewhere in
the Code to other Articles, notably Art. 11. With five other Articles deleted
from the latter part of the Code at previous Congresses (two in Leningrad in
1975, one in Sydney in 1981, and two in Berlin in 1987), only 11 Articles
remained in the Code following Art. 50, yet the numbering extended to 76. For
this reason and because a completely new subject index was being prepared for
this edition, the Editorial Committee decided that a renumbering of the Articles
in the latter part of the Tokyo Code was essential for clarity. This renumbering
was executed in the spirit of the Nomenclature Section’s usual instruction “to
preserve the numbering of Articles and Recommendations in so far as
possible”, in that only the Articles following Art. 50 have been renumbered,
and, by a rearrangement of the ordering of the Articles, the commonly cited
Art. 59, on names of fungi with a pleomorphic life cycle, has retained its
traditional number. The final Article is now Art. 62, an extra Article having
been created by the division of the old Art. 69 (see below).

The Editorial Committee also took the opportunity to clarify the rules on typi-
fication and effective publication by creating a more logical arrangement of
Art. 7-10 and 29-31, respectively. Art. 7 now deals with general matters of
typification, Art. 8 with typification of names of species and infraspecific taxa,
Art. 9 with the various categories of types applicable to such names, and
Art. 10 with the typification of supraspecific names. Art. 29 now addresses the
general issue of effective publication, Art. 30 special cases, and Art. 31 the
date of effective publication.

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Among the more familiar Articles whose numbering has changed are the for-
mer Art. 63 on superfluous names, which is now Art. 52, and the former
Art. 69 on nomina rejicienda, which now forms Art. 56 and 57 (see below). A
tabular key is provided, setting out the changes in numbering of Articles and
Recommendations, as well as their individual paragraphs and Notes, between
the Tokyo Code and the Berlin Code. The numbering of the Articles remained
virtually unchanged between the Seattle Code adopted in 1969 and the Berlin
Code. The Seattle Code includes a “Key to the numbering of the Articles and
Recommendations” for the five editions of the Code from Stockholm (1952) to
Seattle (1972), and the Stockholm Code includes a similar key comparing its
arrangement with that of the Cambridge Rules (1935).

In this edition, the body of the Code is printed in three different type sizes, the
Recommendations and Notes being set in somewhat smaller type than are the
rules, whereas the type of the Examples is even smaller. This reflects the
distinction between the rules (primarily the Articles), the complementary and
advisory material (the Notes and Recommendations), and the mainly explana-
tory material (the Examples). The nature of Articles, Recommendations and
Examples is generally well understood, particularly now that voted Examples
are designated as such (see below), but the role of Notes is less clear. Like an
Article, a Note in the Code states something that is mandatory; it differs from
an Article, however, in that a Note does not introduce any new rule or concept,
but merely spells out something that may not be evident to the user but is
provided for elsewhere in the Code, either explicitly or by implication.

Content, however, is much more important than arrangement or format, al-
though the latter are sometimes the more noticeable. The Tokyo Congress was
noteworthy in that conservation of species names and rejection of any name
that would cause a disadvantageous nomenclatural change were both accepted
by an overwhelming majority on a show of hands. Those who remember the
narrow majorities by which conservation of names of species of major econ-
omic importance and names which represent the type of a conserved generic
name were approved at Sydney and Berlin, respectively, will recognize the
fundamental change that took place in botanical nomenclature at Yokohama.
The Code is no longer a handicap but an encouragement to the maintenance of
nomenclatural stability (see also Greuter & Nicolson in Taxon 42: 925-927.
1993).

The restrictions on conservation of specific names have, therefore, been re-
moved from Art. 14.2, and conservation of the names of species, as for fami-
lies and genera, now simply “aims at retention of those names which best
serve stability of nomenclature”. With the adoption by the Tokyo Congress of
an amendment to the former Art. 69 that provides for the rejection of any name
“that would cause a disadvantageous nomenclatural change”, the Article came
to cover two distinctly different situations and has been divided into two. The
first, the new Art. 56, deals with the general case (i.e. any disadvantageous

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nomenclatural change) and includes the mechanisms by which names can be
rejected as in the previous Art. 69.2. The second, the new Art. 57, relates to the
more restricted case, to which the former Art. 69 was hitherto confined, i.e.
names that have been widely and persistently used for a taxon or taxa not
including their type. Such names continue not to be available for use in a sense
that conflicts with current usage, unless and until a proposal to deal with them
under the conservation provisions of Art. 14 or the rejection provisions of the
new Art. 56 has been submitted and rejected. The separation of Art. 56 and 57
makes even clearer the requirement of the Code (formerly in Art. 69.4) not to
use such a name in a sense that conflicts with current usage unless the appro-
priate Committee has authorized its use.

It is of particular note that the Nomenclature Section at Yokohama, recogniz-
ing the significance of this increased scope for conservation and rejection of
names in ensuring nomenclatural stability, adopted a resolution in the follow-
ing terms: “The Section urges the General Committee and through it all Perma-
nent Committees to make full use of the options that the Code now provides in
order to ensure nomenclatural clarity and stability.” Individual users of the
Code also have a responsibility to help ensure nomenclatural clarity and sta-
bility by making appropriate proposals for conservation or rejection rather than
change names for purely nomenclatural reasons (see also the Congress Resolu-
tion, below).
 

One entirely new concept is incorporated in this edition of the Code, that of
interpretative types to serve when an established type cannot be reliably identi-
fied for purposes of precise application of a name. The original proposal had
used the term “protype” for such a specimen or illustration, but the Nomencla-
ture Section asked the Editorial Committee to determine the most appropriate
term and the Committee adopted “epitype” as better expressing the meaning
(“on top of the type”) and because protype had been used in other senses in the
past. The provision appears in Art. 9.7.
 

Other additions of note decided by the Tokyo Congress and now incorporated
in the Code include provision for the use of the term “phylum” as an alterna-
tive to divisio (Art. 4.2); the requirement that, on or after 1 January 2000
(subject to the approval of the XVI International Botanical Congress) names be
registered (Art. 32.1); the designation of “suppressed works” in which names
of certain categories are ruled to be not validly published (Art. 32.8 and the
new App. V); and the requirement that in order to be validly published a name
of a new taxon of fossil plants must, on or after 1 January 1996, be accompa-
nied by a description or diagnosis in Latin or English, or reference to such, not
in any language as before (Art. 36.3). An extensive revision of Art. 46 has
clarified the situation in which “ex” may be used in the citation of authors'
names and confirmed that the preposition “in”, and what may follow, is bibli-
ographic and not part of the author citation. One of the Permanent Committees

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listed in Div. II was abolished (the Committee for Hybrids) and one was
renamed (the Committee for Fungi and Lichens, now Committee for Fungi).

From time to time Nomenclature Sections have accepted specific Examples
(“voted Examples”) in order to legislate nomenclatural practice where the cor-
responding Article of the Code is open to divergent interpretation or may not
even cover the matter at all. One such Example, adopted by the Tokyo Con-
gress, appears as Art. 8 Ex. 1, making clear what had hitherto been controver-
sial, namely that “cultures permanently preserved in a metabolically inactive
state” are to be considered “preserved permanently” (Art. 8.2), and, although in
a sense “living plants or cultures”, are eligible as types, regularizing a pro-
cedure adopted by yeast taxonomists in particular. Whereas the Editorial Com-
mittee normally has the power to delete, modify or add Examples in order to
clarify the Code, this power does not extend to voted Examples, which the
Editorial Committee is obligated to retain, whether or not they actually exem-
plify the rules. In response to a suggestion, made at the Yokohama meetings,
that voted Examples should be clearly indicated, an asterisk (*) has been in-
serted against each one.

Although proposals made to the Tokyo Congress to provide for the granting of
protection to names (or some aspect of names, e.g. types) on approved lists (the
“NCU proposals”) did not receive the 60 % majority necessary for their adop-
tion, the Section was particularly impressed by the utility of the list of species
names in Trichocomaceae (incl. Aspergillus and Penicillium) in ensuring
nomenclatural stability in that group. Accordingly the Section adopted the
following resolution that authorizes users of names in that family to suspend
application of the Code where necessary: “The Nomenclature Section, noting
that the ‘List of Names in Current Use in the Trichocomaceae’ (Regnum Veg.
128: 13-57. 1994) has already been approved by the International Commission
on Penicillium and Aspergillus of the International Union of Microbiological
Societies (IUMS), urges taxonomists not to adopt names that would compete
with or change the application of any names on that list.”

Apart from the addition of the new App. V referred to above, the Appendices
remain those established in the Berlin Code. App. I deals with the naming of
hybrids; App. IIA lists conserved names of families of algae, fungi, and pteri-
dophytes, which are only conserved against listed rejected names, and App. IIB
those of bryophytes and spermatophytes, which are conserved against all com-
peting names not themselves included in the list; App. IIIA lists conserved
generic names and the corresponding rejected names, and App. IIIB likewise
for species names; App. IV lists names rejected under what is now Art. 56
(formerly Art. 69). Within these Appendices, some restructuring became
necessary, partly because of the growing number of algal classes involved in
conservation (two being added in this Code) and partly because of the present
and foreseeable expansion of some of the smaller Appendices (IIIB and IV in
   rticular). Six major groups are now recognized for the purposes of all these

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Appendices, and are designated by identical capital letters in each Appendix: A
for algae, B for fungi, C for bryophytes, D for pteridophytes, E for spermato-
phytes, and F for fossil plants. In App. IIIA, subheadings with Arabic numerals
are used for the algal and bryophyte classes. Under these headings and
subheadings, conserved names are listed alphabetically, except in the case of
genera of spermatophytes, for which the Dalla Torre & Harms numbering
system and family definitions have been retained once more. It has been made
explicit that, in App. III, all names of diatoms, whether with fossil or recent
types and whether or not the genera include recent species, are listed under
Bacillariophyceae rather than with the other fossil plants.

The procedures for producing this edition of the Code have followed the pat-
tern outlined in Div. III of the Code and traditions well established since the
Paris Congress of 1954. Published proposals for amendment, with comments
by the Rapporteurs, were assembled in a “Synopsis of proposals” (Taxon
42: 191-271. 1993). Results of the Preliminary Mail Vote on these proposals, a
strictly advisory but very helpful expression of opinion, were made available at
registration for the Nomenclature Section of the Tokyo Congress, in the Con-
gress Center of Pacifico, Yokohama, Japan. The Section met from 23 to 27
August, just before the regular sessions of the Congress, and acted on the 321
proposals before it, accepting some 82 and referring another 42 to the Editorial
Committee for modification of the Code. The Section’s decisions were sanc-
tioned by resolution of the closing plenary session of the Congress on 3 Sep-
tember 1993 (see below) and became official at that time. A list of them
appeared along with the results of the preliminary mail vote (in Taxon 42: 907-
922. 1993). A preliminary transcript of the complete tape records of the no-
menclature sessions, prepared by Fred Barrie, Werner Greuter, and John
McNeill, was available to all members of the Editorial Committee at their
meeting in January 1994. The full report of the Section’s proceedings, includ-
ing the essence of the debates and comments made during the deliberations,
has since been published as a separate volume (Englera 14. 1994).

It is the duty of the Editorial Committee, elected by the Section (and, by
tradition, from among those present for the discussions), to incorporate the
decisions of the Congress into the Code and to make whatever strictly editorial
changes are desirable for smooth, consistent, accurate, and clear reading. The
composition of the Editorial Committee usually changes slightly at each Con-
gress, and this was also the case on this occasion. Although the positions of
Chairman and Secretary were unchanged in that Werner Greuter had continued
as Rapporteur-général for the Tokyo Congress and John McNeill as Vice-rap-
porteur, the Committee lost three former members, Riclef Grolle, Frans Stafleu
and Ed Voss, the two latter having served for several terms on the Editorial
Committee. Frans Stafleu had been Vice-rapporteur and Secretary of the Edi-
torial Committee from 1954 to 1964, Rapporteur-général and Chairman of
the Committee from 1964 to 1979, and as President of the Nomenclature Section

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at Berlin in 1989 he had returned to the Committee for the preparation of the
Berlin Code; while Ed Voss had served continuously on the Committee since
1964, being Vice-rapporteur and Secretary of the Committee from 1964 to
1979, Rapporteur-général and Chairman of the Committee for the 1981 Sydney
Congress, and a member of the Committee for the Berlin Code. Although their
experience was missed, the Committee was very well served by their replace-
ments: Fred Barrie, Missouri Botanical Garden (currently on assignment at the
Field Museum, Chicago); Per Magnus Jørgensen, University of Bergen; and
Piers Trehane, Wimborne, Dorset, U.K. (co-opted to replace Alan Leslie,
Royal Horticultural Society, Wisley, U.K., elected to the Committee in Yoko-
hama but unable to serve); all of whom joined most effectively in the work of
the Committee.

After circulation of a first draft of the text of the new Code, the Editorial
Committee met at the “Botanischer Garten und Botanisches Museum Berlin-
Dahlem” from 2-7 January 1994. All 11 members of the Committee were
present for this traditional and essential meeting that explores as exhaustively
as possible the clearest and most concise way to express in the Code the
decisions of the Nomenclature Section. A myriad of editorial details must be
addressed to ensure that the resulting work is unambiguous to all users, regard-
less of their primary language. The Editorial Committee recognizes that com-
plete clarity and consistency are hardly achievable. Some instances of impre-
cise, conflicting, or otherwise unsatisfactory wording may still remain in the
Code. Any effort to resolve certain points would result in extending the oper-
ation of the Code or restricting it, depending upon one's reading of the present
text, and would not, therefore, be covered by the Editorial Committee's man-
date.

The method by which some or all scientific names are set off in printed text
varies substantially between different countries and language traditions. Per-
haps as a result, there has been an unevenness in this regard in different
editions of the Code. In an attempt to achieve uniformity, the Sydney Code and
the Berlin Code italicized all scientific names at the rank of family and below,
i.e. those for which priority is mandatory. The present Editorial Committee
recognized that this policy was rather illogical, and, in the Tokyo Code, all
scientific names falling under the provisions of the Code are italicized, whereas
informal designations appear in Roman type. For example, in Art. 13.1 (d) the
ordinal names Uredinales, Ustilaginales, etc. are italicized, whereas the infor-
mal group name “fungi” is not. The Editorial Committee considers this to be
the most appropriate form of presentation in a code of nomenclature but does
not aim to impose this as a standard to be followed in other publications, which
may have different editorial traditions, often of long standing.

Consistency within the Code regarding bibliographic style and details, in a
manner which is non-confusable and agreeable to all users, has been among
our prime editorial concerns. Standardization aids are now available which did

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not exist years ago, providing an almost complete coverage of high standard
for various categories of data. We have consistently used “TL-2” (Stafleu &
Cowan, Taxonomic literature, ed. 2; with Suppl. 1 & 2, by Stafleu & Mennega)
for book title abbreviations, “B-P-H” (Botanico-Periodicum-Huntianum) and
its Supplement for the citation of journal titles, and Brummitt & Powell’s
Authors of plant names (Royal Botanic Gardens, Kew, 1992), for author cita-
tions. The style of citation used in the Names in Current Use (NCU) lists, and
explained there in detail (see Regnum Veg. 126: 912. 1993), has been followed
throughout. For the countless nomenclatural citations in the Appendices this
standardization was a major undertaking. Whereas new-style entries were read-
ily available for most of the conserved names of families (from Regnum Veg.
126) and genera (from Regnum Veg. 129), they had to be established anew for
nomina rejicienda. Standardized author citations were introduced by Paul Kirk,
International Mycological Institute, Egham, for all such names that had been
downloaded from the Index nominum genericorum database by Ellen Farr,
Smithsonian Institution, Washington – which were only those that are expli-
citly marked “nom. rej.” in that database (perhaps slightly more than one half
of the total). Norbert Kilian, Berlin, working under an IAPT contract, carried
out all the remaining standardizations manually. Brigitte Zimmer, Berlin, did
extensive consistency checks.

The updating of App. II-IV, meaning not only the additions and changes re-
flecting adopted proposals but also extensive verification of extant entries
which in several cases resulted in substantial editorial corrections, was done in
conjunction with experts acting either in their capacity of Editorial Committee
members or Permanent Committee secretaries. Paul Silva took care of the algal
entries; Vincent Demoulin, assisted by Walter Gams, of the fungal ones; Gea
Zijlstra not only provided the bryophyte additions but also many updates and
amendments resulting from her work with the Index nominum genericorum;
Dan Nicolson prepared the additions for pteridophytes and spermatophytes, for
the latter of which Dick Brummitt provided countless careful contributions;
and Bill Chaloner took responsibility for fossil plants. The great and generous
help of them all is gratefully acknowledged.

Whereas the index to App. III, completely computer-generated from its con-
tent, has not undergone any major change, the main index has been completely
restructured and divided into two halves (scientific names and subject index) in
an effort to make the content of the Code more readily accessible to teachers
and students of botany as well as to those who apply the Code on a regular
basis. This complete restructuring and rewriting, which we hope will be seen as
a significant improvement on previous versions, was carried out by Piers Tre-
hane. It proved to be a demanding and exhausting chore, for which he deserves
all our gratitude.

The final editing of the whole text, including the Appendices and Indices, was
undertaken by Werner Greuter in close contact with other members of

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the Editorial Committee, a circumstance made easier by the development of fax
transmission and electronic communication. Brigitte Zimmer, assisted by Nor-
bert Kilian for the Appendices portion, produced camera-ready copy of the
text.

In addition to those who have helped produce this new edition of the Code,
botanical nomenclature depends on the scores of botanists who serve on the
Permanent Nomenclature Committees that work continuously between Con-
gresses, dealing principally with proposals for conservation or rejection, and
those others who are members of Special Committees, reviewing and seeking
solutions to the problems assigned to them by the Nomenclature Section of the
previous Congress. Botanical Nomenclature is remarkable for the large number
of taxonomists who voluntarily work so effectively and for such long hours, to
the immeasurable benefit of all their colleagues who must use plant names and
on whose behalf this word of sincere thanks is expressed.

Ultimately, however, plant nomenclature is not governed by a bureaucracy of
committees but, in an open and democratic manner, by the community of its
users represented by the enrolled members of International Botanical Con-
gresses. The user-driven process by which plant nomenclature is regulated is of
utmost importance for a Code which, having no “teeth” in the way of penalties
for infringements, entirely depends on user consensus for its universal applica-
tion and implementation.

The International code of botanical nomenclature is therefore published under
the ultimate authority of the International Botanical Congresses. The Tokyo
Congress at its final plenary session adopted the following resolution relating
to nomenclature:

“Considering the great importance of a stable system of scientific names of
plants for use in the pure and applied sciences and in many other domains of
public life and economy;

“noting with satisfaction recent important improvements in the International
code of botanical nomenclature and ongoing efforts to explore new avenues for
increased stability and security in the application of plant names;

“the XV International Botanical Congress urges plant taxonomists, while such
work continues, to avoid displacing well established names for purely nomen-
clatural reasons, whether by change in their application or by resurrection of
long-forgotten names;

“resolves that the decisions of the Nomenclature Section with respect to the
International code of botanical nomenclature, as well as the appointment of
officers and members of the nomenclature committees, made by that section
during its meetings, 22-27 August, be accepted.”

This resolution goes far beyond the traditional act of ratification of nomencla-
ture actions and Permanent Committee nominations by Congress. By it, and

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through the International Union of Biological Sciences under whose auspices
those Congresses are held, plant taxonomists are urged to become the cham-
pions of nomenclatural stability. Name changes made for purely nomenclatural
reasons (as opposed to those that result from changing taxonomic concepts,
hopefully reflecting a progress of our science) are to be avoided.

Does this mean that the present Code is a document of little consequence, to be
set aside each time its application leads to results felt (by some) to be disagree-
able? Certainly not. The Code now offers generous new ways to avoid nomen-
clatural changes by proposing the conservation or rejection of names, and these
opportunities are to be used. Should these not suffice, new provisions may
have to be devised and incorporated in the future.

The Code is a living and adapting body of law, and as long as it keeps evolving
in tune with changing needs and new challenges it will keep its authority and
strength. The Tokyo Code is, we believe, a significant landmark in this ongoing
adaptive process.
 

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        Key to the numbering of the Articles, Notes and Recommendations

The key includes only those items that either are new, or newly deleted, or
whose numbering has changed. Examples are omitted since they can easily
be traced via the indexes, through the plant names mentioned.

1. Berlin Code to Tokyo Code

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2. Tokyo Code to Berlin Code

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                            IMPORTANT DATES IN THE CODE

DATES UPON WHICH PARTICULAR PROVISIONS OF THE CODE BECOME

EFFECTIVE

ARTICLES INVOLVING DATES APPLICABLE TO THE MAIN TAXONOMIC

GROUPS

ARTICLES DEFINING THE DATES OF CERTAIN WORKS

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[ to body of the 1994, Tokyo Code ]