Sample of handwriting
While most European floristic works contain keys for the identification
of families, genera, and species, extra-European ones usually have the
keys replaced by a systematic survey, which makes it cumbersome to
identify the family to which the plant under investigation belongs. It
is, of course, often possible to recognize it immediately by the
presence of a conspicuous character, but there are also many cases in
which it is not that easy, and then written aid such as given in the
present work is desired. The few works of this kind presently available
generally consider the typical features of the family only, while they
neglect the numerous exceptions. In the present work, however,
especially in the second edition, all exceptions have been considered as
far as possible, the less significant ones in footnotes¹,so
that plants with characters that are different from the ones typical for
the family may also be identified correctly./p
In the choice of differentiating characters those have been preferred
that can be seen in a flowering plant with the naked eye. As far as
nomenclature, delimitation, and description of the families are
concerned Engler and Prantl's Die natürlichen Pflanzenfamilien
has been used as the basis for the revision of the present work; in
addition, however, many other manuals have been consulted, especially
Bentham and Hooker's Genera plantarum, De Candolle's
Prodromus, Baillon's Histoire desplantes, and Engler's
Pflanzenreich, as well as various floras.
The key is followed by a description of all families of flowering
plants² which mainly serves to check the result of the
identification for its correctness, as well as an explanation of the
most important botanical technical terms occurring in the book. The
addition of figures has been decided against; one finds suitable ones
especially in Engler's Syllabus der Pflanzenfamilien.
Vienna, in May 1917
¹ incorporated into the key in the current edition
² ommited in the current edition
(p.r) but added as hyperlinks to the biodiversity-site of L. Watson and M. J. Dallwitz in this html-version
top
Introduction
For the identification of a flowering plant the first step usually is
to discover to which family it belongs. With some experience, the
families commonly encountered in one's area of interest are soon
known, but when dealing with specimens from other places, notably
those from the vast and rich subtropics and tropics, there is much
less certainty. The pertinent literature is often not readily
available as it is often found only in expensive, rare or obscure
books, or journals, present only in a few specialised institutes.
Basically only a few keys to the families of flowering plants of the world have ever been produced, the best known of which at present is Hutchinson's Key to the families of flowering plants (1973); less well-known are Lemée's Tableau analytique des genres monocotylédones (1941) (incl. Gymnosperms) and his Tableau analytique des genres dicotylédones (1943), and Hansen and Rahn's Determination of Angiosperm families by means of a punched-card system (Dansk Bot. Ark. 26, 1969, with additions and corrections in Bot. Tidsskr. 67, 1972, 152-153, and Ibid. 74 1979, 177-178).¹ Of note also are Davies and Cullen's The identification of flowering plant families 2nd ed. (1979), which, however, deals only with the families native or cultivated in North Temperate regions, and Joly's Chaves de identifição das familias de plantas vasculares que ocorrem no Brasil, 3rd ed. (1977), which may be useful in other tropical areas too.
There are a number of excellent keys prepared by an Austrian, Franz Thonner (1863-1928), which deal either with European genera (1901, 1903, 1918), or African ones (1908, 1913, 1915), or with all families of the world (1891. 1895, 1917). Some of these have apparently been completely overlooked, others have been known only to a few, and then sometimes served as a base for keys of their own, thereby again influencing keys by others see Derived works .
At Dutch Universities extensive use has long been made of the Anleitung zum Bestimmen der Familien der Blütenpflanzen, 2nd ed. (1917, Friedländer, Berlin), which to our experience has proven to be the most reliable work in existence. Of course, as the keys deal with a highly complex subject, they require close attention for a profitable use. They may therefore perhaps have scared off even professional botanists, who then had to take recourse to other simpler and therefore less dependable ones. In a few places, Thonner's keys were better appreciated and even introduced in undergraduate courses, for instance by Pulle and his school in the Netherlands, by Sørensen in Copenhagen, and in Brazil at first by an unknown translator and later by Rawitscher, Alvim and Joly. Elsewhere the Anleitung (1917) has been little known, rare and, for many, inaccessible, as it is in German.
It seemed, therefore, a worthwhile venture to translate it into English. A start was made by Leeuwenberg in the early 1960s, but other obligations soon delayed progress. About twelve years later, he mentioned this in a casual conversation with Geesink and Ridsdale, who had just begun a translation of their own, and his efforts were thankfully incorporated. Veldkamp joined shortly afterwards. It rapidly became apparent that mere translation would be unsatisfactory: the innumerable footnotes should also be worked into the main key; the nomenclature should be brought up to date; and something should be done about the many new families accepted by some authors since Thonner's time. For the latter we have largely restricted ourselves to those mentioned by Airy Shaw in his revision of Willis' A dictionary to the families of the flowering plants and ferns, 8th ed. (1973) and Hutchinson's The families of flowering plants, 3rd ed. (1973), these being currently the most consulted manuals. These 'segregated' families have now all been accounted for.
We have also tried to check the many curious or aberrant genera, but have undoubtedly missed many. The keys have not become easier because of all these additions. The number of key couplets has increased from 812 (excluding footnotes) in the 1917 edition, to 2117 in the present one. Nevertheless, they provide a useful means of identification and force students as we know from experience, to make a clear and careful analysis and logical interpretation of the various parts of the plant. We hope that all those interested through profession or hobby may be aided in a rapid identification of their material, and that we have made Franz Thonner and his works slightly better known and appreciated.
We invite the user to point out errors, difficulties, and omissions. It should then be indicated in which couplets difficulties arose with a suggestion as to how they might be remedied. A representative specimen would be useful, even if only on loan. Any assistance will be acknowledged in future editions. Communications should be sent to J. F. Veldkamp, P.O. Box 9514, 2300 RA Leiden, the Netherlands².
Leiden, September 1980
¹ this key is available as windows version 3.0 at http://www.mip.berkeley.edu/meka/meka.html (p.r)
² adres changed (p.r)
Thonner spent about 30 years creating his Anleitung (1917), apparently without much outside help. We were more fortunate and had others to advise and assist us. First of all we thank the Director, Staff, and students of the Rijksherbarium, Leiden, for providing the facilities, expert knowledge, and trial runs of the key, respectively. Other help was promised by many, but given by few. We had many helpful suggestions and criticisms but have applied the remarks in our own fashion, hence all mistakes and misinterpretations made should be attributed to us.
Our sincere thanks are due to
R.C. Bakhuizen van den Brink Jr.(Leiden, various)
M.M.J. van Balgooy (Leiden,Elaeocarpaceae, various)
G.M. Barroso (Rio de Janeiro,Lepidocordia)
B.G. Briggs (Sydney, Proteaceae,Restionaceae)
R. Clarysse (Meise, Thonner/De Wildeman correspondence)
M.J.E. Coode (Kew, Elaeocarpaceae)
T.A. Cope (Kew, various)
T.B. Croat (Saint Louis,Araceae)
P.J. Cribb (Kew, Orchidaceae)
R. Dahlgren (Copenhagen, esp. Monocotyledones)
F.G. Davis (Kew,Compositae)
J.J. Dransfield (Kew, Palmae)
L.L. Forman (Kew, Fagaceae)
P.S. Green (Kew,Oleaceae)
C. Grey-Wilson (Kew, Balsaminaceae)
B. Hansen (Copenhagen, Balanophoraceae, various)
C. Hansen(Copenhagen, Melastomataceae)
R. M. Harley (Kew, Labiatae)
P. Hiepko (Berlin, Opiliaceae)
Ding Hou (Leiden,Anacardiaceae, Aristolochiaceae, Celastraceae, Hippocrateaceae)
S.S. Hooper (Kew, Cyperaceae)
D.R. Hunt (Kew,Commelinaceae)
B.R. Jackes (Atherton, Epacridaceae,Vitaceae)
L.A.S. Johnson (Sydney, Gymnospermae)
Hsuan Keng (Singapore, Gymnospermae)
R.Kool (Leiden,Ixonanthaceae)
K.U. Kramer (Zurich, various)
J. Kuyt (Lethbridge, dicotyledonous parasites)
D.J. de Laubenfels (Syracuse, Gymnosperms)
P.W. Leenhouts (Leiden,Burseraceae, Connaraceae, Sapindaceae)
D.J. Mabberley (Oxford, Adoxaceae, Meliaceae, Sterculiaceae)
W. Marais (Kew, Chloanthaceae. Liliaceae)
W. Margadant (Utrecht, biohistory of Thonner)
S. Mayo (Kew, Araceae)
J.F. Maxwell (Singapore, Melastomataceae)
N.L. Menezes (São Paulo, Joly key)
R. van der Meijden (Leiden, Haloragaceae,Polygalaceae)
H.P. Nooteboom (Leiden, Simaroubaceae,Symplocaceae)
W.R. Philipson (Christchurch, Calycanthaceae,Idiospermaceae, Monimiaceae)
P.H. Raven (Saint Louis,promotion in the U.S.A.)
J.W.A. Ridder-Numan (Leiden,various small families)
R.E. Rintz (Mt. Clemens,Asclepidiaceae)
M.J. Sands (Kew, Balanitaceae,Begoniaceae) Schmid (Noumea, New Caledonian taxa)
C.G.G.J. van Steenis (Leiden, Bignoniaceae, Sonneratiaceae,various)
B.C. Stone (Kuala Lumpur, Pandanaceae, Rutaceae)
M. Tamura (Osaka, Ranunculaceae)
N.P. Taylor (Kew,Cactaceae)
B.N. Teensma (Leiden, Portugese)
J. Thompson(Sydney, Tremandraceae)
C.C. Townsend (Kew,Amaranthaceae)
P. van der Veken (Gent, various)
W. Vink (Leiden, Hamamelidaceae, Sapotaceae, Winteraceae)
E.F. de Vogel (Leiden, Apostasiaceae, Orchidaceae, seedlings)
J.N. Westerhoven (Hirosaki, Ikeno key)
W.J.J.0. de Wilde (Leiden, Myristicaceae, Najadaceae, Passifloraceae)
K.L. Wilson (Sydney, Cyperaceae, Juncaceae).
We thank the Botanical Garden, Berlin, for the opportunity to show a poster there during its tercentenary celebration in September 1979. We assume that at least those who ran off there with a free copy of the Preliminary Version (or obtained one later) but never bothered to comment have found it to be without blemish.
We are most obliged to P. W. Leenhouts, Leiden, who was willing to assist us in correcting the proofs and who painstakingly checked the numbering again.
The reproductions of the pictures of Thonner were made by B. N. Kieft and the drawings for the plates by J. van Os, Leiden.
Finally, we thank our wives, who first had to miss us on Thursday evenings ('Thonnerstagabend'), and later had to spend holidays during which manuscripts were polished and retyped, but never complained too much.
top
Franz Thonner Life (1863 - 1928)
Franz Thonner was born in Vienna on 11 March 1863 as the son of Franz
Thonner, cordwainer at the Imperial Court of Vienna, and Therese
Schnaubelt. Very little is known of his life. Most of the following has
been extracted from the sources mentioned below, which usually give only
the briefest information.
He was educated at the Theresien Gymnasium in Vienna, and then studied Law for a single semester (in Vienna ?) His interest then turned to the Natural Sciences, to which he remained devoted for the rest of his life. He studied in Vienna and Berlin, but apparently never obtained an academic degree. In 1891 he married Marie Svoboda, a Czech; there is no record of any children. They first settled in Dresden, but in 1903 moved to Vienna, where they remained until 1920. Afterwards they went to Smichov, a suburb of Prague, where Thonner died on 21 April 1928.
Somehow Thonner was a gentleman of private means, which allowed him to pursue the subjects of his interest and thus became what in German is called a 'Privatgelehrter'. It is remarkable that he turned to larger projects only, at least only one brief article (1897) from his hand is known to us. When only 28, he had already written and published a key to the families of flowering plants of the world, the Anleitung (1891), a unique work, as no one before him had prepared a similar treatise. He paid for this publication himself, as he did for all his subsequent ones. The absence of an experienced publishing house perhaps explains why his works remained almost unnoticed in the scientific journals of that time and they remained virtually unnoticed to the present day. Possibly to increase his market and also to include his later additions, he translated them into French or English, in which languages he was well versed. For further details see the next chapters on Bibliography and Derived works .
Together with his wife he often travelled through Europe and North Africa. Twice he went on his own to the Ubangi and Mongala Districts of the Belgian Congo. Both expeditions were cut short: the first (23 August\eml22 October 1896) because the Congolese went off with his canoe and some of his equipment and collections; the second (28 January\eml16 March 1909) because of illness, so he collected much less than he had intended.
He wrote journals on each expedition in German (1898, 1910) and in French (1899, 1910), which contain a wealth of orginal botanical, ethnological, and linguistic observations. About the botanical collections, two books were also written, for the publication of both of which he also paid (De Wildeman & Durand, 1900; De Wildeman, 1911). In the first book, De Wildeman observed that although only 120 botanical collections were made 50 were new for the area, and 23 species and 4 varieties were new to science. It is rare that such a proportion would be obtained; he apparently had a keen eye and had gone well prepared. In the second book, De Wildeman took the opportunity to publish extensively on the flora and vegetation of the area, an action heartily approved of by Thonner.
Several of the new species were named after him, but unfortunately the only genus named in his honour, Thonnera De Wild. (Annonaceae) has turned out to be a synonym of Uvariopsis Engl. & Diels (see Eponymy ).
Next to nothing is known about his private life and methods. He apparently rarely visited the Naturhistorisches Hofmuseum in Vienna (Thonner, in litt., K. -H. Rechinger, Vienna, pers. comm.) mainly to check identifications and to select material for his illustrations. He probably corresponded with the Botanisches Museum in Berlin, since he asked De Wildeman to send duplicates of his collections to Diels, Engler, and Harms, but the Berlin archives were destroyed during World War II. We procured part of his correspondence, mainly with De Wildman in Brussels (March 1899— May 1921), from which some information could be gleaned. Although the two must have known each other for a long time, met occasionally and visited the Opera together, the brief notes remain formal. Their wives corresponded also; how tantalizing to know more of what they had to tell each other! Thonner’s handwriting was even and clear, as is shown by the accompanying sample , one of the few where mention is made of the Anleitung (1917).
For his plates he privately employed an artist, J. Fleischmann, who was for a short time assisted by another one, not named, who made the analytical drawings. At least one of his manuscripts, written by him in stenography, was worked up to a definitive version by an unknown secretary.
To us his major works are the various keys to the genera and families. Although we have studied the Anleitung (1917) for a long time now, we can still only guess about his methods. Each of his keys was basically different from the preceding ones, as may be noted from the main couplets, a change which necessitates an entirely new structure. He apparently based himself especially on Engler and Prantl's Die natürlichen Pflanzenfamilien (1895—1 915) and Das Pflanzenreich as far as it had appeared, as can be seen from the sometimes verbatim quotations. It is interesting to note that many genera originally misplaced there key out in the Anleitung (1917) to the families where they have subsequently been transferred to. Whether he had an extensive file or a prodigious memory we do not know, but the results speak for themselves: they have never been surpassed.
In 1911, he was awarded a Belgian distinction, apparently at the request of De Wildeman, but as yet we have not discovered which nor the citation of the award.
During World War I he sent part of his private library to Great Britain as a payment for the publication of The flowering plants of Africa (1915), as transfer of funds was prohibited. After the War, his fortunes dwindled with the incredible inflation of those times, and he wrote that he tried to subsist by translating novels between English, French and German. His correspondence, if any, with De Wildeman after 1921 is lacking from the archives of Brussels.
Of his last years in Smichov, we know nothing, except that he fell victim to a chronic disease and died on 21 April, 1928 at the age of 65.
The only obituary that we have received (through the kind efforts of the librarian of the Naturhistorisches Museum, Vienna) was in a Viennese anthropological journal; to the botanical world he remained virtually unknown both in life and death.
top
Franz Thonner - Bibliography
top
Franz Thonner - Derived works
Thonner's efforts remained more or less unknown. Two botanical works
were based on his expeditions to the Belgian Congo (De Wildeman
& Durand, 1900; De Wildeman, 1911), of which the first sold
only 4 copies in the first year (he gave away a number as
complimentary copies). Apparently his two journals did not fare much
better, but were perhaps of sufficient importance as an obituary
appeared in an anthropological journal. On his keys a few others were
directly or indirectly based, and are listed here. Possibly there are
more, of which we would like to be notified; they can easily be
detected by the sequence of the main couplets, if no mention is made
in the introduction.
In 1893 Ikeno published an abbreviated Japanese translation of the Anleitung (1891).
Henriquez (1897) translated it into Portuguese, but the journal in which it appeared did not have a wide circulation, and this translation was for instance apparently unknown in Brazil.
Pittier translated the Analytical key (1895) into Spanish and adapted it for use in South America. The first edition (1917) was used by Standley (1920), who was apparently unaware of its Anglo-American origin, for his Mexican keys. Standley used the second edition of Pittier's Clave (1926) for his Panaman flora (1928). A third edition appeared in 1939.
Joly (1977) discussed in length the discovery in 1939 of a manuscript key in use in Viçosa, Brazil, which turned out to be derived also from the AnaLytical key (1895). This key was mimeographed several times before it was revised by Rawitscher and Rachid-Edwards (1956), and again independently revised and restricted to Brazil by Alvim (1943) and Joly (1969).
We ourselves also distributed a stencilled Provisional Edition (1979) of 106 copies to various institutes and colleagues for comment.
Thonnera De Wild. (Annonaceae) = Uvariopsis Engl. & Diels
Aframomum thonneri De Wild. (Zingiberaceae)
Antholyza thonneri De Wild. (Iridaceae) = Gladiolus atropurpureus Bak.
Bertiera thonneri De Wild. & Th. Dur. (Rubiaceae)*
Casearia thonneri De Wild. (Flacourtiaceae)= C. barteri Mast.
Clerodendrum thonneri Gurke (Verbenaceae)*
Combretum thonneri De Wild. (Combretaceae) = C. paniculatum Vent.
Conopharyngia thonneri (Stapf) Stapf (Apocynaceae) = Tabernaemontana thonneri De Wild. & Th. Dur. ex Stapf
Crotonogyne thonneri De Wild. (Euphorbiaceae) = C. poggei Pax
Dichapetalum thonneri De Wild. (Dichapetalaceae) =D. bangii (F. Didr.) Engl.
Dicranolepis thonneri De Wild. & Th. Dur.(Thymelaeaceae) = D. buchholzii Engl & Gilg
Dinophora thonneri Cogn. (Melastomataceae) = Phaeoneuron dicellandroides Gilg
Dioscorea thonneri De Wild. & Th. Dur.(Dioscoreaceae) =D. preussii Pax
Harveya thonneri De Wild. & Th. Dur. (Scrophulariaceae)*
Hygrophila thonneri De Wild. (Acanthaceae)
Impatiens thonneri De Wild. & Th. Dur.(Balsaminaceae) = I. irvingii Hook. f. ex Oliv.
Isolona thonneri (De Wild. & Th. Dur.) Engl. & Diels (Annonaceae)*
Listrostachys thonneriana Kranzl. (Orchidaceae) = Diaphananthe pellucida (Lindl.) Schltr.
Loranthus thonneri Engl. (Loranthaceae) = Agelanthus brunneus (Engl.) v.Tiegh.
Macaranga thonneri De Wild. (Euphorbiaceae) = Alchornea laxiflora (Benth.) Pax & Hoffm.
Millettia thonneri De Wild. (Leguminosae)*
Monodora thonneri De Wild. & Th. Dur. (Annonaceae) Isolona thonneri Engl. & Diels
Ouratea thonneri De Wild. (Ochnaceae)*
Pycnocoma thonneri Pax (Euphorbiaceae)*
Rhabdophyllum thonneri (De Wild.) Farron (Ochnaceae)= Ouratea thonneri De Wild.
Rinorea thonneri De Wild. (Violaceae) = R. welwitschii (Oliv.) 0. Ktze
Rourea thonneri De Wild. (Connaraceae) = Roureopsis thonneri Schellenb.
Roureopsis thonneri (De Wild.) Schellenb. (Connaraceae)*
Scaphopetalum thonneri De Wild. & Th. Dur. (Sterculiaceae)*
Sesamum thonneri De Wild. & Th. Dur. (Pedaliaceae) =?S. mombazense De Wild. & Th. Dur.
Tabernaemontana thonneri De Wild. & Th. Dur. ex Stapf (Apocynaceae)*
Thunbergia thonneri De Wild. & Th. Dur. (Acanthaceae)
Uragoga thonneri De Wild. & Th. Dur. (Rubiaceae) =?Psychotria sp.
Urera thonneri De Wild. & Th. Dur. (Urticaceae)*
Vitex thonneri De Wild. (Verbenaceae)
top
Introduction and Notes
Each of Thonner's keys was different from the preceding ones. As the
present work was initially intended to be a mere translation of the
Anleitung (1917), we have not changed its structure, even when
some major couplets are notoriously difficult. On the whole Thonner has
managed to keep the key as simple as possible, and so have we; but
highly technical questions which need some botanical experience and a
good dissecting microscope cannot be avoided. Some will therefore find
it a difficult book to use at first. We would suggest some methods to
facilitate use.
Start with some well-known plants, or back-track your way from a few familiar families; in this way, you will become acquainted with the keys and the terms used. It will then be noted that they are based on relatively few characters which turn up time and again. Unfortunately complete material is required: sterile and exclusively male specimens cannot be identified, female or fruiting ones will cause great problems. For these, Hansen & Rahn's punch-cards will limit your options.
The key is strictly dichotomous (except for some couplets in the Concise key to the groupings ) each couplet is composed of two leads. The latter are usually composed of two parts again, separated by a dash¹. The first part should be contradicted by the opposing lead of the couplet. The second part contains additional information; features mentioned here may or may not be present in taxa referable to the opposing lead; they are merely given as a possible further aid. In both parts the characters are given in the morphological descriptive sequence, if feasible, and not according to their diagnostic 'weight'. This has been done to facilitate reading; many keys have been made more difficult and confusing because of their scrambled text. Distribution is often also given as an aid, but is of course only valid for plants not introduced, cultivated, or escaped; especially weedy or showy plants should be suspect, while exact distributions are still not always known in some cases.
¹ This covers the printed text, in the HTML-version you are looking at every part of an key-couplet is numbered and separated by a short line, every key-couple is separated by a longer line (p.r.)² text changed in link(p.r).Read both leads carefully and completely!
Try to visualise their intentions and use your brains! Most misidentifications are due to careless, hasty, sloppy, superficial, and unimaginative reading. Note the numbers encountered on a slip of paper, marking uncertain choices to facilitate retracing if you go wrong.Do not pick and poke about the specimen!
The various leads are in a haphazard morphological sequence and you should try to limit destruction of your specimen as much as possible; once it has been torn apart it will be difficult to re construct and you may need another flower of your precious material!Boil a single flower!
You can always boil another if required. Fresh material is often easier to handle after boiling, too. Examine it in a Petri-dish under sufficient water so that it will neither float away, nor be obstructed by the surface of the water; a drop or two of detergent will drive off air bubbles (chaffy flowers as in Cyperaceae, Gramineae do not need to be boiled at all, some detergent in water is sufficient); soak overnight in strong ammonia when the floral parts are flimsy and glued together, as in Balsaminaceae and Orchidaceae.Make a short diagnosis!
It is often useful to do so, working from the outside inwards in such a way that nothing is inadvertently damaged that may be needed later, for instance after you have found the correct family and have to use the material with other keys all over again. See ² Scheme for a diagnostic description . Simple sketches will also be helpful, for instance a floral diagram (aestivation!) and shape of fragile parts.
Add these notes and sketches, and as much as can be saved and dried of the remnants of the object to the specimen for future reference.
A difficult question was how to mention the many new families
accepted by some since Thonner's time. We have largely limited ourselves
to those in Willis' Dictionary (1973) and Hutchinson's
Families (1973). In some cases, we are convinced that their
distinction is unacceptable, in others that they are indeed distinct,
but in many cases, as in the Liliales, Saxifragaceae s.l. few
specialists agree. So who are we to profess expertise to make a
satisfactory choice among the options? As this key is primarily intended
for practical use, and not as a taxonomic manual, we thought we should
have some leeway; in principle we decided to follow Melchior's
Engler's Syllabus der Pflanzen familien, 12th ed. (1964), but
deviated from this course where it suited us.
It was also borne in mind that Thonner himself based his family concept
on Engler and Prantl's Pflanzenfamilien. One should therefore not
invoke our arbitrary use of names in an argument on the taxonomic
distinctness of such a family. The fact that supposedly related taxa
often key out close together should not be extrapolated to doubtful
cases, as the keys are artificial; such coincidences are merely
fortuitous (yet, there may be something in it, one never knows!).
The segregated families are noted in brackets as in the
Exkursionsflora (1901) and other works. Genera and some
supra-generic taxa have been noted when we had the impression that these
would key out exclusively in a particular lead, but only when one or two
taxa seemed to be involved, e.g.
(Escalloniaceae:Itea) … Saxifragaceae'.
This means that only Itea keys out here, which is sometimes
treated as an Escalloniacea, which family is treated here as part
of the Saxifragaceae.
N.B.(p.r) In the HTML version all these families ,tribes or even genera mentioned as families on the biodiversity-site of L. Watson and M. J. Dallwitz are indirectly linked to this site.
Some notes of warning: a taxon may well turn up in several places without being noted everywhere, partly because of the artificiality of the key (an apetalous species will end up in a different place from its petaliferous congeners), whereby it may run down together with more than two other taxa in places, partly because we overlooked it. More taxa than those mentioned may actually key out to one place, but we were not aware of it. The taxon may not belong here at all (we hope not), but was included because of an error by us, or because the descriptions in the literature consulted were faulty (by necessity we had to lean heavily upon other works). We are convinced that not all aberrant taxa have been included, partly because we simply were not aware of their existence, partly because the conventional, less controversial, and often huge families such as the Euphorbiaceae , Myrtaceae, and those of the Tubiflorae have been much less studied.
Some taxa may appear to have been misplaced in the key but are not the result of a misinterpretation. Instead, their 'wrong' inclusions act as fail-safes, many of which were already built into the system by Thonner in his footnotes. In several instances, features are not what they seem to be, but this is then only known to someone familiar with the situation, who will then not use these keys in the first place. Bracteoles may be adnate to a perianth and then resemble a calyx, suggesting a place among the Chori- or Sympetalae; petals may be so cohesive that they appear connate and mislead the unsuspecting to the Sympetalae, on the contrary they may be fused at the very base only, appearing free, suggesting a place among the Choripetalae. As this key aims to be practical, we have maintained despite objections from some learned correspondents, that the plant should also key out according to the interpretation of the structure which would appear most logical to someone not hampered by knowledge, even if this is morphologically incorrect.
Thonner's keys were rarely illustrated and more plates in the current work would have been useful, but as we wanted to remain as concise as possible, we have refrained from adding more. One is therefore referred to the other works mentioned by Thonner and in our introduction, and to the many other text books. For world families. Heywood's recent Flowering plants of the world (1978) provides an inexpensive and well-illustrated survey.
The terms employed will usually cause no great difficulty. We have tried to use as few technical terms as possible, including those required in the Glossary at the end of the book, sometimes ad absurdum; for those we missed one should consult Jackson's A glossary of botanic terms, 4th ed. (1928). We hope to have solved the problem about hypo-, pen-, and epigyny by the footnote to Couplet 548 and by Plate&sub1 1, while the most common types of ovules have also been depicted (Plates 2 and 3). One ambiguous term has been pointed out by various colleagues which we refuse to change: epipetalous (or -tepalous) means 'opposite to the petals (or tepals), but not necessarily inserted on them'. Others use these words to indicate insertion only, and not relative position, whereby the term alternipetalous (or -tepalous) has no uninomial, easy counterpart.
¹ available via glossary(p.r)Thonner included short descriptions of the families and they are indeed very useful for speedy reference. We had to omit these at present and the user is referred to other manuals. It was not possible to prepare reliable succinct diagnoses, even when so many are available. To copy these from existing literature proved unsatisfactory, as descriptions are often not complete enough to fit the Scheme for a diagnostic description as is given on page xxvi, a most surprising discovery. Their deletion has one minor advantage to the buyer of this book: it would otherwise have been much thicker and more expensive.
top
Scheme for a diagnostic description
Note position, number, coherence, shape, and size where applicable.
Vegetative characters
Habitat (if not terrestrial).
Life form (annual, perennial, shrub, tree, climber, liana).
Indument (check young parts), type of hairs.
Leaves (arrangement, simple/compound, type of nervation), presence of translucent lines or dots, crystals (strong pen light useful here, mind your eyes!)
Stipules (absence/presence, check young shoots, scars).Floral characters
Inflorescence (type, mode of branching );bracts; bracteoles. Flower (sex, actino-/zygomorphic, hypo-/peri-/epigynous), see Plate 1); aestivation (in bud) of sepals, petals, tepals; hypanthium.
Disk (absence/presence; extra-/intra-staminal).
Stamens (alterni-/epipetalous or -tepalous); filaments (free/ad-/connate); anthers (dehiscence by slits, pores, valves; in-/la-/extrorse—check in bud).
Styles; stigmas (number of lobes may be indicative of number of carpels and locules).
Ovary (superior/(hemi-)inferior— Plate]); locules; placentas; ovules (position, type, see Plates 2 and 3, number per locule/o vary).
Fruiting characters
Fruit (type, dehiscence, consistency).
Seeds (number per locule or fruit; surface; appendages and their position<\i>).
Embryo (form, position: the radicle points to where the micropyle was!.
Endosperm (absence/presence, consistency).
Origin
only for truly indigenous plants.