Bid. J. Linn. Soc., 3, pp. 295-299
September 1971
The history of the Index Kewensis
R. D. MEIKLE, F.L.S.
Royal Botanic Gardens, Kew, Surrey
CONTENTS
Origin
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The work of Daydon Jackson
The shortcomings of the original Index Kewensis .
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The demands of modern taxonomy
The possibilities of mechanization and computerization .
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ORIGIN
In the autumn of 1881, towards the close of his life, Charles Darwin decided to
devote some of his money to the advancement of those sciences ‘which had been the
solace of what might have been a painful existence’.
Why he should have decided to direct his benevolence towards the compilation of
an index of flowering plant names is not exactly known, but one suspects that at least
some pressure was exerted by his old friend and ally, Sir Joseph Hooker, who was at
this time Director of the Royal Botanic Gardens, Kew.
Darwin’s (and Hooker’s) original intention was nothing more grandiose than the
publication of a new edition of Steudel’s Nomenclator Botanicus. The second edition
of this useful compilation was already 40 years old, and in most respects very incomplete
and unsatisfactory. But an interleaved copy at Kew had been kept more or less up to date
by the addition of new names and synonyms, and it was felt that the needs of science
would be met if this additional information were incorporated in the proposed new
edition, and the whole work re-cast to agree with the family and generic concepts
outlined in Bentham & Hooker’s Genera Plantarum.
With such a scheme in mind, the then Assistant Director at Kew, M r William
Thiselton-Dyer, approached Benjamin Daydon Jackson on 8 December 1881, after a
committee meeting of the Linnean Society. Daydon Jackson had already published
a useful guide to the literature of botany, and was, in the opinion of Hooker, Asa Gray
and other eminent botanists, the person best qualified to superintend the publication
of the new Steudel.
THE WORK OF DAYDON JACKSON
Three days later Daydon Jackson wrote to Thiselton-Dyer giving the project
his qualified approval and, on 14 December 1881, he went to Kew to lay his detailed
plans for staff, stationery and equipment before Sir Joseph Hooker. He also suggested
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a very important modification of the proposed scheme. Steudel cited names and authors,
but gave no literature references. Daydon Jackson recommended that these references
should be added, and estimated that the whole task could be completed in six years.
Sir Joseph agreed and, on 4 February 1882, Daydon Jackson, armed with Bentham &
Hooker’s Genera Plantarum, Pfeiffer’s Nomenclator, De Candolle’s Prodromus (kindly
donated by Sir Frank Crisp) and Buek’s Index to the Prodromus, began work, aided by
two young clerks. The young clerks must soon have become bored by the monotony
of botanical indexing, for Daydon Jackson records that no fewer than 11 assistants
passed through his hands before the job was finished. Only one, M r H. A. Hutchinson,
subsequently librarian to the Royal Horticultural Society, stayed for any length of
time.
Like most botanists, Daydon Jackson was an optimist as regards time. He thought
six years would be sufficient for the compilation of the Index; in fact the first fascicle
did not appear until 6 September 1893, more than 11 years after the starting date.
Charles Darwin died on 19 April 1882, but his family continued to support the Index
Kewensis project.
In a short article published in the Journal of the Royal Horticultural Society (1921,
49: 224-229), Daydon Jackson outlined his modus operandi.
First of all, the generic names and their synonyms were extracted from Bentham
& Hooker’s Genera Plantarum, ‘each retained genus being followed on the sheet by
the sunk genera, and each sunk genus repeated separately on its own sheet, with a
cross-reference to the maintained genus’. Then the species were entered on the same
sheets, each genus, with its attached species, being enclosed in a stout labelled cover.
A third clerk-a Swede, who was very quick and accurate-assisted with this task,
and with the more time-consuming business of adding literature references to all the
accumulated lists of names, Since there are said to have been 168 boxes of names
(weighing rather more than a ton) and about 30,000 covers of genera and species, the
magnitude of the task can be imagined. T h e preliminaries, up to the point of adding
literature references, occupied about 18 months, the remaining nine and a half years
were largely taken up with adding these literature references and seeing the work
through the press. Daydon Jackson admits that he did not trace every name back to its
source: ‘By experiment I found that up to 1850 practically all names were accounted
for in the main works consulted, but from that year every endeavour was made to
extract new species and names from original works to the end of 1885.’ The ‘main
works’ referred to were Richter’s Codex Botanicus Linnaeanus, Petermann’s Index,
De Candolle’s Prodromus and Monographia, Kunth’s Enumeratio, Walper’s Repertorium and Annales, Bentham’s Flora Australiensis, Martius’s Flora Brasiliensis,
Ledebour’s Flora Rossica, Hooker’s Flora of British India and Boissier’s Flora
Orientalis.
A major disaster was narrowly averted in 1891 when Sir Joseph Hooker suddenly
announced that certain major literature references must be altered. Even 33 years
later one can sense the panic. Daydon Jackson protested and ‘finally, bowing to the
opinion of many distinguished botanists’, Sir Joseph gave way. But, as Wellington
said of the Battle of Waterloo, it was ‘a damned close run thing’.
Just before printing began, M. ThCophile Durand, a Swiss botanist working at
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Brussels, offered manuscripts which would have brought the contents of the original
volumes up to 1890. In the event this offer was not accepted, and these materials
were subsequently incorporated in an 1886-95 supplement published in Brussels
between 1902” and 1906, on behalf of the joint editors, Daydon Jackson and Durand.
After Durand’s death in January 1912, the Clarendon Press, who had printed the
original volumes, acquired the unsold stock of the first supplement, and remained
thenceforth publishers and printers of the work. Daydon Jackson’s association with
the Index Kewensis came to an end with the appearance of the final fascicle of Supplement 1 in 1906. By the time the first part of Supplement 1 had been issued, M r s. T.
Dunn had already completed a second supplement, which was published in 1904.
and which carried the Index up to 1900.
THE SHORTCOMINGS O F T H E ORIGINAL INDEX KEWENSIS
T o those who had had to make do with Steudel’s Nomenclator, with or without
manuscript up-datings, the publication of the Index Kewensis must have come as an
unqualified boon. In time, however, readers became conscious of certain shortcomings. Chief amongst these was the fact that the Index Kewensis was too closely
akin to Steudel, and that it should not really have been called an ‘Index’. An Index
should cite names, references, dates (and perhaps distributions) without passing
any taxonomic judgments, but simply accounting for all names which had been
validly published under the Rules of Botanical Nomenclature. A Nomenclator
goes further; it not only cites names, but tells us which names are to be accepted and
which rejected, and what is to be regarded as the correct name of any particular taxon.
It is as much an arbiter of taxonomic opinion as of nomenclature. The original volumes
of the Index Kewensis regarded the generic concepts of Hooker and Bentham as infallibly
and unquestionably correct, even if other names had better claims under the principles
of priority. Likewise a principle, subsequently known as the ‘Kew Rule’, was applied
throughout; this rule maintained that the correct epithet for a species was the one it
was given when it was first attached to the ‘correct’ or ‘true’ generic name, that is, the
generic name employed in Bentham and Hooker’s Genera Plantarunt. Nowadays we
find it difficult to understand this mystical concept of a ‘true’ genus, but in 1900 most
British botanists, including the formidable James Britten, were happy to accept it
as a sensible and sound principle of nomenclature. And so the Index Kewensis continued
to be a Nomenclator up to 1913, when, under pressure of international opinion, the
‘Kew Rule’ was abandoned, and the 4th Supplement became a straightforward Index,
giving the names and references to all validly published generic and specific names of
flowering plants, without passing taxonomic judgments or attempting to tell us which
name is to be maintained, and which discarded. This non-committal objectivity
has been consistently maintained since 1913, and the Index Kewensis has remained
unchanged in character save in a few minor details: in Supplement 7 (1921-5) all
new genera were listed for the first time under their families at the end of the volume;
and in Supplement 10 (1936-40) all descriptions accompanied by an illustration were
asterisked for the first time.
* Title page is dated 1901-1906, but the first fascicle probably did not appear until late January or
February 1902.
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R. D. MEIKLE
The original Index Kewensis was defective in two other respects. As has been mentioned, Daydon Jackson did not attempt to trace all names to their original sources,
but was content to accept the references given by D e Candolle, Pfeiffer, Bentham and
other eminent authorities. As a result many errors, some of them very serious ones,
often affecting the priority of a name, were innocently incorporated in the Index;
indeed the whole problem of deciding the priority of names was often left open through
failure to give the dates of the publications cited. If it should at any time be decided
to re-issue the original volumes, or to provide a cumulative index of all flowering
plant names published to date, it will clearly be necessary to check all these older
references and to add the missing dates. Such a task would almost amount to re-writing
these volumes.
THE DEMANDS OF MODERN TAXONOMY
In two other respects the Index Kewensis, however valuable, does not fully meet
all the demands of present-day taxonomy: the quinquennial publication of the supplements often means that there is a very substantial time-lag between the first publication
of a name and its appearance in the Index Kmensh. This may not seem a very serious
matter, but it can be a source of considerable irritation to a taxonomist who publishes
a name in good faith, having scrutinized all the relevant parts of the Index, only to
find that he has been anticipated by another author, with a name now some years
old but not yet listed. A more serious shortcoming is the omission of the names of
taxa above the rank of genus to the level of family, and the omission of the names of
taxa between genus and species, as well as those below the rank of species. I t must be
remembered that all scientific names from the level of family downwards are equally
subject to the International Rules and to the principles of priority, and, even if species
and genera are still the basic concepts of taxonomy, it is nonetheless essential that
some guidance should be given to names published in other ranks. With increasing
sophistication and refinements in taxonomy, the use of infraspecific taxa, especially
the subspecies, becomes more frequent in monographs, floras and revisions, and modern
authors also tend to offer elaborate analyses of families and genera, sometimes without
any more nomenclatural assistance than is provided by a retentive memory and copious
notes. Few of us would care to be dogmatic as regards the nomenclature of taxa omitted
from the Index Kewensis.
THE POSSIBILITIES OF MECHANIZATION AND COMPUTERIZATION
Finally, since we are concerned with modern methods in providing biological
information, we must, for a moment, consider the possibilities of mechanization.
Few of us possess private copies of the Index Kewensis, and few libraries have attempted
complete integrations of all the volumes and supplements of this extensive work.
Such an integration, in a modified form, does exist at Kew, but a computer is required
to produce fully integrated, cumulative indexes at regular intervals. Clearly some
form of selective retrieval of data would be even more useful, especially if it permitted
the rapid retrieval of not only all the names published in any particular family or
genus, but all the names recorded in the floras of one particular part of the world,
or proposed by one particular author. Such services are nowadays provided in many
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departments of learning and must, sooner or later, be made available in plant taxonomy,
a science which, more than most, calls for easy access to exact and complete bibliographical data. T h e authorities at Kew are justifiably proud of the Index Kewensis
and of the very substantial contribution it has made to botany; they are also conscious
of the shortcomings of the present Index and have given long and careful consideration
to plans for the extension of its scope, and for a programme of computerization which
should, in time, fully satisfy the demands of all those who are concerned with the
classification and naming of plants. Economic considerations and present restrictions
on the engagement of additional staff alone delay the implementation of this scheme;
the plans are there, and will be acted upon as soon as circumstances permit.