What We Need to Know about Scientific
An Example with White Clover
Gary W. Fick* and Melissa
ABSTRACT
Thereis a shortageof currentinformation
on the nomenclature of cropsprepared
for the classroom.
Thisarticle is written
for studentsandinstructorsin the plantscienceswiththe goal
of illustrating the applicationandusefulnessof plant nomenclature andrelated taxonomic
concepts.Whiteclover (Trifoliumrepens L.) makesa goodexample.It is familiar to many
students,is easily grownfor classroom
demonstrations,
andhas
an interesting nomenclature
to matchits great diversity. Its
nomenclature
is usedto explaininfraspecificnamesandauthority designations.Thehistoryof scientific names
for whiteclover
illustrates howand whynameschangeand howprecision in
scientific communication
canbe increasedby the use of scientific names.Themainexamplefor increasedprecisionis the
comparison
of the size groupsof whiteclovercultivars withthe
scientific namesfor the infraspecificranksof the samegroups.
Typespecimensandthe associatedtaxonomicdescriptionsare
requiredfor scientific namesandmakepermanent
andobjective referencepoints. Thescientific namesrecommended
for
the three common
size groupsof white clover are the following: (i) TrifoliumrepensL. f. repens,the smallor wildgroup;
(ii) T. repensf. hollandicum
Erithex Jfiv. &So6,the intermediate or Dutchgroup;and(iii) T. repensvar. giganteumLagr.Foss., the large or Ladinogroup.
TrlE
trsE of scientific (Latin) names necessary for
precise communication of biological information
across time (history) and space (languages and regions).
As students, we are usually required to memorizescientific names, but it is more important that we knowhow
to interpret and use the scientific names we encounter.
Unfortunately, taxonomic instruction seems to be frequently slighted in the applied plant sciences. This article
and its accompanying appendices are intended to help
teachers and students with limited taxonomic training
better understand, interpret, and use the scientific names
of plants.
White clover (Trifolium repens L.) was chosen as the
example species because most plant science students
(Homosapiens L.) will be familiar with this widely distributed and common
plant. It can be easily grownin pots
for interesting classroom demonstrations that illustrate
various taxonomic concepts. The nomenclature of white
clover also provides ready examplesof three points that
often puzzle plant science students: (i) why "binomial"
names are sometimes so long and complicated, (ii) how
G.W.Fick, Dep.of Soil, Crop,andAtmospheric
Sciences,andMelissa
A. Luckow,
BaileyHortorium,
CornellUniv., Ithaca, NY14853.Contribution fromthe Dep.of Soil, Crop,andAtmospheric
Sciences,Cornell Univ.Received2 Feb. 1990.*Corresponding
author.
Publishedin J. Agron.Educ.20:141-147
(1991).
Names:
A. Luckow
scientific names add precision to communicationsabout
crops, and (iii) whyscientific namesfor a particular kind
of plant can change. Our primary goal is to illustrate and
clarify the issues related to these three questions. In addition, we hope this article will encourageapplied scientists to consult taxonomists when they have questions
about plant nomenclature.
WHY NAMES CAN BE SO LONG
Most persons with biological training will remember
the rudiments of biological nomenclature. A species name
consists of two words: a genus name, which is capitalized, and a specific epithet, whichis not capitalized. Both
are in Latin and are either underlined or italicized. In
addition, the species name is followed by an authority
designation that refers to the author of the name. In the
species namefor white clover, Trifolium repens L., Trifolium is the genus name,repens is the specific epithet, and
Linnaeus(abbreviatedL.) is the authority. If it is not confusing, the genus name may be abbreviated and the
authority deleted in subsequent uses in the same paper.
For example, the above may be shortened to T. repens
once it is given in full.
Whenwe need to find and use a scientific name, we
can look it up in a handy flora or a standard reference
such as Hortus Third (3). The confusion begins when
find a nameof more than two Latin words or an authority
that is long and complicated. For a complexspecies like
white clover, additional Latin epithets sometimesfollow
the species nameto indicate infraspecific subdivisions of
the species. Such nameswill have designated ranks, usually subspecies (ssp.), variety (var.), or form (f.),
latter (lower) rank encompassedby the former. A group
of similar plants at any rank is called a taxon (plural,
taxa). The name for a taxon below the rank of genus
should also have an authority that follows the name, e.g.,
T. repens ssp. nevadense (Boiss.) D.E. Coombe.The long
authority for the subspecies nevadenseindicates that this
kind of white clover was first described by Boissier (abbreviated Boiss.) in a different genus, as a separate
species, or at a different rank. It was later madea subspecies by D.E. Coombe.
The current rules of plant nomenclature (14, 18) allow
the taxonomist to define the factors that separate ranks,
and this can cause confusion (4). Subspecies are usually
defined as geographically distinct parts of a species, but
both subspecies and varieties are variously defined as geographic, morphological, or economic(i.e., wild vs. weed
vs. crop) groups within a species (4). To avoid confusion,
most taxonomists refer to subspecies or varieties but not
both. Forms usually represent morphologically distinct
J. Agron.Educ., Vol. 20, no. 2, 1991 141
Table 1. Comparisonof citation systems found in the "long style"
of authority designation used with scientific namesand reference listings used in society journals. Three taxa of white clover
serve as examples.
Example
Authority
or reference
Scientific namesand authority designations
1. Trifolium repens L., Sp. PL 767. 1753.
2. T. repens L. f. hollandicumErith ex Jhv. & So~, A MagyarnOvdnyvilhg
kdzikonyve 330. 1951.
3. T. repens L. var. giganteumLagr.-Foss., F1. Tarn Garonne95. 1847.
References
1. Linnaeus, C. 1753. T. repens p. 767. In Species plantarum.
2. J~vorka, S., and R. Sod. 1951. T. repens L. p. 330-331. In A Magyar
n0vdnyvil~g
k~zikOnyve.
Akaddmiai
Kiadd.
3. Lagreze-Fossat,
A. 1847.T. repens,
p. 94-95.In Florede Tam et
Garonne.
Rethord,
Montauban.
but minor kinds of variability.
Subsequent examples
illustrate infraspecific classification, but it should already
be clear that more than a binomial name might be needed
with some complex species.
Authority designations can also get complicated. The
authority citation is really a reference to scientific literature. The science of plant taxonomyhas developed its
ownconventions of style for citing original references,
and there are three methods in use:
1. The short style in which the citation is reduced to
the author’s name, often abbreviated, e.g., Trifoo
lium repens L.
2. The name-and-year style in which the publication
year is added, e.g., T. repens L. 1753
3. The long style in which the full reference is cited,
e.g., T. repens L., Sp. PI. 767. 1753
The short style is commonlyused in scientific journals.
The name-and-year style is useful when names are being
comparedfor priority. The long style is used in taxonomic
references where all possible ambiguities must be eliminated (Table 1). The abbreviations for authors and publications are standardized in reference works consulted
by taxonomists(23, 24) so that even the short style should
be traceable to its original source. For this to be possible, care must be given to exactly reproduce authority
designations. Good scientific
writing requires that
authority designations be included for species and infraspecific namesthe first time they are used. It is simply a matter of citing one’s sources. (AppendixI gives
more details about the rules of plant nomenclature.)
BEING PRECISE
Because crop scientists work mainly with species, varieties, and cultivars of plants, most of their taxonomic
questions concern the names of species and infraspecific
groups. White clover is a particularly rich examplewith
at least 232 namedcultivars (6) and about 200 variations
of scientific names for wild populations (9, 25). Many
of the 200 + scientific namesare redundant or illegitimate under the rules of nomenclature, but recent reviews
(15, 25, 27, 28) showthat there are about eight varieties
(or subspecies) in the wild populations (Appendix II).
The International Code of Nomenclature for Culti142
J. Agron. Educ.,
Vol. 20, no. 2, 1991
vated Plants (5) specifies that all infraspecific taxa maintained only by cultivation should be namedas cultivars
(cultivated varieties). Thus, scientific names for subspecies, varieties, and forms should only be used to refer
to wild plant populations. Such populations often
represent the progenitors of moderncrops, the source of
genes in breeding programs, and specialized populations
of weeds and forages that have differentiated spontaneously in agricultural situations. As a complexof cultivated and wild kinds, white clover challenges our
capabilities for precise scientific identification belowthe
species level.
The cultivated code (5) also allows "groups" of similar cultivars to be recognized. Agronomists frequently
divide white clover cultivars on the basis of plant size into
small, intermediate, and large groups (8, 11). The size
differences are important because they affect adaptation,
productivity,
and management options. For example,
small kinds are less productive than large kinds, but small
kinds tolerate close continuous grazing. Large kinds
should be given recovery periods following close grazing.
Caradus (6) briefly described 232 cultivars of white
clover namedin the literature, and relative size was one
of the main points of most descriptions. Because of variable environments and previous interbreeding, there is
complete overlapping of size amongso manykinds. For
comparison, Caradus (6) used old and widely knowncultivars as reference points. Amongthe oldest cultivated
kinds of white clover used for size reference are the following:
1. ’Kent Wild White’: a small cultivar certified in
England in 1930 (6)
2. ’Dutch’: a widely exported agricultural ecotype of
intermediate size that originated in the Netherlands
(6). Records of importation of Dutch white clover
seed to England predate 1750 (8)
3. ’Ladino Gigante Lodigiano’: a large agricultural
ecotype knownin Italy from at least 1760 (6). It was
widely exported, and in the U.S., the term "Ladino" denotes both the old cultivar name and the
group of large cultivars in general (11)
The abovelist illustrates the rules for namingcultivars:
cultivar names are to be capitalized, not in Latin (with
exceptions), of no more than three words, and enclosed
by single quotation marksthe first time they are used (5).
Unfortunately, many cultivars that are properly named
have not been carefully described or formally registered.
Consequently, comparisons like those of Caradus (6) can
be very useful to a plant breeder or farm advisor who
is already familiar with white clover. However,relative
comparisons are not clear to someoneunfamiliar with the
reference cultivar, and a reference cultivar maydisappear
when it becomesobsolete. Cultivar nomenclature can be
ambiguousbecause it lacks permanent reference points.
Unlike a cultivar name, a scientific nameis based on
a preserved specimen(the type specimen) and a published
description that distinguishes that taxon from all other
kinds (14, 18). Consequently, scientific names provide
about as precise and permanent a reference point as is
possible. Erith (8) was the first to use scientific names
Table 2. Measurementsof the size for the three cultivated
of white clover.
Plant
characteristic
groups
Small group
(Wild)
Intermediate
group (Dutch)
Large group
(Lad/no)
mostly 25-65
mostly 50-180
6-16
mostly <25
< 120
mostly 50-75
mostly 75-250
9-22
mostly 25-35
> small group
about 2.0
up to 600
mostly >300
up to 55
mostly >35
mostly >300
>3.3
mostly 15-20
mostly 15-25
up to 35§
mm
Petiole length~
Petiole length~
Leaflet length~"
Leaflet length¶
Pedunclelength’f
Stolon diam.¶
Inflorescence
diam.t
FromErith (8).
FromHartwig(16). Plant characteristics are repeated for different sources.
FromSzab6 (25).
Zohary and Heller (28) reported most are 30-35 mm.
to define, in effect, wild progenitors of the three following cultivar groups:
1. var. sylvestre Alef. ("wild white clover," of small
size)
2. var. sylvestre Alef. race hollandicumErith ("white
Dutch clover," of intermediate size)
3. var. sylvestre Alef. race giganteum (Lagr.-Foss.)
Erith ("Lodi or Italian white clover," of large size)
These three groups are clearly associated with the old
reference cultivars. However,they provide additional information because they have type specimens for reference and published descriptions to distinguish them. In
addition, Erith (8), Szab6 (25), and other workers measured the variability in each of the three groups and
recorded actual size ranges (Table 2). Althoughthe size
parameters have some inconsistencies and may not be
completely accurate for all environments where white
clover is nowgrown, they certainly add quantitative detail to relative statements about size. Becausereference
standards exist for scientific namesbut not for those of
cultivars, the descriptions of cultivars as well as wild plant
populations becomemore precise if they can be related
to infraspecific taxonomic categories.
WHY NAMES CHANGE
One of the main functions of botanical nomenclature
is to provide a basis for determining the accepted scientific namefor each kind of plant. A basic rule is that the
accepted name will be the oldest name, beginning with
Species Plantarumwritten by Linnaeus in 1753 (14, 18).
A scientific name can be changed if an older name with
a type specimen and properly published description is
found for the same kind of plant. Since T. repens is found
in the starting reference, it cannot be replaced because
of priority. However, it has replaced other names. The
Russian botanist C. von Steven (26) named a kind
white clover T. nothum Steven in 1856, apparently believing that it differed from the species already named
by Linnaeus. T. nothum is now regarded as a legitimate
but incorrect name and is said to be a synonymof the
accepted name, which is T. repens.
Another reason that a namecan change is the development of new taxonomic concepts. Botanist K.B. Presl (21)
believed that the genus Trifolium should be divided, one
part becoming a new genus Amoria. White clover thus
becameA. repens (L.) K. Presl. This name is nowregarded as a synonym of T. repens by most taxonomists because they do not believe the Amoria taxon warrants
species status. If they did, A. repens wouldbe the correct name. The authority designation of A. repens is
another example of the citation of two authors for one
name. The authority in parentheses (the "parenthetical
authority") is retained because the delineation of the taxon and the type of specimenare associated with that reference. The authority outside the parentheses (the
"combining authority") is added because the taxonomic position (the genus or rank) has been changedby placement of the taxon into a "new combination" by that
authority and reference.
The evolution of taxonomicconcepts leading to several
scientific namechanges is illustrated by the development
of scientific names for the cultivated groups of white
clover (AppendixIII). Erith’s system (8) was the first
recognize three progenitors of the cultivated groups, but
as far back as 1847, Lagreze-Fossat (19) proposed three
size taxa for white clover: (i) T. repens L. (the taxon of
Linnaeus); (ii) T. repens var. giganteumLagr.-Foss. (the
large kind); (iii) T. repens var. microphyllumLagr.-Foss.
(a "very small" kind).
In 1866, Alefeld (1) simplified the concept by splitting
the above groups in half and reducing the number of
groups to two: (i) T. repens var. silvestre Alef. (the wild
kinds); and (ii) T. repens var. cultum Alef. (the cultivated
kinds). Ascherson and Graebner (2) and Gams(10)
agreed with that approach and formulated a taxonomy
to represent the degree of relatedness of the taxa in question. All were placed together in T. repens var. typicum
(Aschers. & Graebn.) Gamsin Hegi. Within this group
were three forms: (i) f. giganteum (Lagr.-Foss.) Gamsin
Hegi (large kinds); (ii) genuinum(Aschers. & Gra ebn.)
Gamsin Hegi (small and intermediate kinds); and (iii)
f. microphyllum (Lagr.-Foss.) Gamsin Hegi (very small
kinds). Erith’s 1924 revision (8) mentionedin the previous section replaced var. typicurn with the older name
var. sylvestre Alef. She also split f. genuinumto recognize a distinct group of intermediate size, i.e., race hollandicum Erith. The result was three size-based taxa for
the progenitors of moderncultivars, with both hollandicum Erith and giganteum (Lagr.-Foss.) Erith given the
rank of race. Erith (8) stated that f. microphyllum
represented only environmentally stressed specimens of
the small kind, var. sylvestre. It appears that no one has
proven otherwise.
The names proposed by Erith (8) have also been
changed, though the taxa she recognized still stand. After
Erith’s work, the rules of nomenclature were formalized
and specified that the nameof a taxon should be repeated
at lower ranks with the same type specimen. Thus, names
such as typicum, genuinum, and sylvestre were replaced
by repens in the scientific names for the kinds of white
clover. J~vorka and Sob (17) used the more standard rank
of form (f.) as an alternative to the races of Erith (8),
and Zoharyand Heller (28) reinstated the older treatment
of giganteum as a distinct variety. The three wild proJ. Agron. Educ.,
Vol.
20, no. 2, 1991 143
Table3. Aclassificationof the wildprogenitors
of cultivatedwhite
clover that combinesagronomic
andtaxonomicperspectives.
Eachscientific nameis in a column.
Smallgroup Intermediategroup
Largegroup
Rank
lWild~
{Dutch)
{Ladinol
Trifolium
Tdfolium
Genus
Tdfolium
Species repensL.
repens
repens
Variety repens
repens
giganteum
Lagr.-Foss.
hollandicum
Form
repens
giganteum
Erith ex Jhv. &Sod
genitors of cultivated white clover maynowbe designated
as follows:
1. Trifolium repens L. f. repens (the small kind)
2. T. repens f. hollandicum Erith ex Jfiv. & Sob (the
intermediate kind)
3. T. repens var. giganteum Lagr.-Foss. (the large
kind)
The names for the intervening ranks of these taxa are
given in Table 3.
FROM THE PRECISE TO THE RIDICULOUS
After all this academicintricacy, someoneis likely to
ask, "Whynot just say the white clover is a small, intermediate, or large kind, and forget the Latin?" In some
cases, that maybe adequate, but the adjectives are relative and the species is highly variable across genotypes
and environments. Scientific names provide well-defined
reference points that aid communication.The counter argumentfollows that perhaps the desired result could be
accomplished by simply designating a cultivar group
name, i.e., "Wild, Dutch, or Ladino." This would be
appropriate if only cultivated types were involved, but
in a species like white clover, the scientific namesof the
wild progenitors makethe same distinction while adding
the precision of type specimens. Whenprecise scientific
communication is important, scientific names including
infraspecific ranks can be very helpful. Of course, cultivar and cultivar group names should also be used
whenever they apply.
Other infraspecific names for kinds of white clover
have also been proposed, but their use could lead to confusion. Examplesinclude T. repens var. tetraphyllum Lej.
& Cour. (the four-leaf clover), var. fusco-maculatum
Godet (the bloodwort with purple leaf blotches), and
roseum (Peterm.) Gams in Hegi (purple-flowered white
clover). Since the characteristics of distinction are under
rather simple genetic control (27), a four-leaved, purpleblotched, purple-flowered kind could be found. What
should it be named?For such cases, phenotypic or genotypic codes seem more appropriate than scientific names.
The guiding principle for the use of scientific names
should be to increase precision and to avoid confusion.
APPENDIX !
Additional Rules of Nomenclature
The most frequently applied standards of plant nomenclature were explained in the maintext, but there are addi144
J. Agron.Educ., Vol. 20, no. 2, 1991
tional rules that govern how plants are named. Those
rules are published in the International Code of Botanical Nomenclature (14) and are revised every 6 yr. The
rules apply to taxa that are organized into ranks as follows: class, order, family, genus, species, subspecies, variety, and form. Classes are the largest units (have the
highest rank), forms the smallest. The rules of nomenclature only designate the order of ranks and do not attempt to define them. The rules at the species level and
below are emphasized here because they are used most
frequently by crop scientists.
1. The accepted name for a species or infraspecific
rank is the oldest legitimate ("legal") namefor the rank
published in or after Linnaeus’ Species Plantarum in
1753. More recent names for the same taxon are called
synonyms. Synonymsresult when an author inadvertently
gives a new nameto a plant that has already been named.
Exceptions to the rule of priority are strictly regulated
by the code. The choice of beginning publication was
purely arbitrary, but it nowserves as the starting point
for all botanical nomenclature.
2. For a nameto be legitimate, it must be both effectively and validly published. Effective publication means
that the name appears in printed matter distributed to
the general public and maintained in science libraries.
Valid publication meansthat the namesatisfies four additional requirements outlined below.
3. To be valid, each name must have a genus and
specific epithet that are in Latin (see main text). The
names should agree in gender, but correction of gender
and modernization of spelling, e.g. silvestre for sylvestre, are allowed after the nameis published. Additional
Latin epithets for infraspecific ranks are allowed if they
meet the other criteria for validity. Infraspecific ranks
in addition to those designated in the code are allowed,
e.g., "race" and "convariety."
4. To be valid, each scientific namemust have a published description that distinguishes that plant from all
others (see main text). For any new name published after 1958, the description must be in Latin.
5. To be valid, each name must have an identifiable
author. If the name has been changed in rank or genus,
the original author is given in parentheses and is called
the parenthetical
authority. The author making the
change follows outside the parentheses and is called the
combiningauthority (see main text). Nobis (n. or nob.),
mihi (m.), and hoc locus (h.c.) are used in place of the
authority to show that the author of the publication is
the author of the name. Abbreviation for authors’ names
follows strict rules. The correct abbreviations for authorities can be found in references (23) and (24).
6. To be valid, each name must have a preserved reference specimen known as the type specimen (see main
text). The type specimenis the permanentreference point
for a name, so if a name is changed in genus or rank,
the type specimen can be located through the parenthetical authority.
7. Several other special rules apply to authors’ names.
For example, in Trifolium repens L. f. hollandicum Erith
ex J/~v. & Sob, the term ex means that Erith first proposed the name but that J~tvorka and Sob provided the
valid description. Another commonlyencountered case
is exemplified by T. repens L. f. cultum (Alef.) Gamsin
Hegi. The taxon named culture by Alefeld was given a
new rank by Gamsin a book otherwise written by Hegi.
8. There are several errors that will cause a validly published nameto be illegitimate (nom. illegit.). One example is a later homonym,
i.e., an author inadvertently chose
a name that exactly duplicated a name used earlier for
a different taxon. The error is indicated as follows: T.
macrorrhizum Boiss. non Waldst. & Kit. Bossier corrected the mistake himself by altering the rank: T. repens
L. var. macrorrhizum Boiss. His name does not occur
as the parenthetical authority because the first nameis
illegitimate.
9. A namemayalso be illegitimate because it is superfluous (nom. superfl.). For example, the Italian taxonomist Biasoletto proposed the name T. prostratum
Biasol. as an alternative for T. biasolettii Steud. &
Hochst. named in his honor. Because he knew the earlier namealready existed for the taxon, the name he proposed was superfluous. Nymanlater altered the rank of
the same taxon in T. repens L. ssp. prostratum Nym.
Biasoletto is not recognized as the parenthetical authority because his namefor the taxon is illegitimate.
10. Imprecise descriptions, careless interpretations, or
disregard for rules of the code can lead to misidentification of a taxon or misapplication of the name, and such
mistakes may be perpetuated in the literature. The abbreviation auct. (for authors) is used to showthat many
authors have repeated the same mistake. The designation
T. repens L. var. latum, auct. Amer. shows that many
Americanauthors have used that namein error. (In this
case the name was invalid.)
11. The following terms are also used in scientific
names:
hort., hortulanorum: "found in gardens," a cultivar.
nom. nud., nomen nudum’. "naked name," published
without description.
p. p., pro porte: "in part," only part of a taxon is included.
pro syn., pro synonymo: published "as a synonym."
s. auct., sine auctorum: published "without author."
This only begins the interesting and intricate details of
botanical nomenclature. Crop scientists maynot need to
knowall the rules, but they should be able to cite a valid
name, including the authority, and recognize the complicated cases where expert advice is needed. To determine the proper name and authority, two references are
available: Index Kewensis(22), listing all plant names,
their authorities, and place of publication; and the Gray
Card Index (13), similar to (22) but containing only
World plant names.
APPENDIX II
Diversity of the Wild Populations of White Clover
One of the more convincing arguments of the need for
infraspecific taxa is the existence of distinct wild populations within a species. Technical descriptions and keys
to the main infraspecific taxa of white clover are avail-
able in Coombe(7), Gillett (12), and Zohary and Heller
(28). Eight or nine main infraspecific groups are generally recognized, but specialists have not agreed on the
rank of each taxon, and this results in variation in the
number of groups. The most authoritative source is the
recent monograph on Trifolium by Zohary and Heller
(28), and the following list is based on their eight varieties, here subdivided to accommodatetwo other widely
recognized kinds. Wherethe rank is debated, the accepted
name at the alternative rank is included in brackets.
Trifolium repens L.
Taxon1: var. biasolettii (Steud. & Hochst.) Aschers.
Graebn. [ssp. prostratum Nym.]
¯ flowers pale pink, heads mostly 14 to 18 mmdiam.
¯ petioles densely hairy, leaflets mostly 5 to 10 mm
long
¯ range: dry habitats and sunny slopes in the Mediterranean zone from France to Turkey
Taxon lb: IT. occidentale D.E. Coombe= T. repens ssp.
occidentale (D.E. Coombe)M. Lainz; treated as
synonym of Taxon 1 by Zohary and Heller (28)]
¯ similar to Taxon 1 but with slightly larger flower
heads (mostly 20-24 mmdiam.) and sparsely hairy
petioles
¯ range: sand dunes along English Channel and Atlantic coast of southern Europe
Taxon 2: var. giganteum Lagr.-Foss. [var. repens f.
giganteum (Lagr.-Foss.) Gamsin Hegi]
¯ flowers white to pale pink, heads > 30 mmdiam.
¯ petioles mostly glabrous, leaflets mostly > 35 mm
long
¯ range: wild populations have been reported from
around the Mediterranean
Taxon3: var. macrorrhizum Boiss. [treated as synonym
of Taxon 1 by Greuter et al. (15)]
¯ similar to Taxon1 but with white flowers and thicker
taproots
¯ range: mountains of Turkey and Iran
Taxon 4: vat. nevadense (Boiss.) C. Vicioso [ssp.
nevadense (Boiss.) D.E. Coombe]
¯ flowers white and heads _< 20 mmdiam.
¯ petioles mostly glabrous, leaflets _< 10 mmlong
¯ range: mountains of Spain and Portugal
Taxon 5: var. ochranthum K. Mal~ ex Aschers. &
Graebn. [ssp. ochranthum (K. Mal~) Ny~r.]
¯ flowers yellowish and heads mostly 25 to 30 mm
diam.
¯ petioles glabrous, leaflets _< 13 mmlong
¯ range: mountains of Romania and Bosnia
Taxon6: var. orbelicum (Velen.) Fritsch [ssp. orbelicum
(Velen.) Pawl.]
¯ flowers cream colored and heads _< 25 mmdiam.
¯ petioles glabrous, leaflets mostly 6 to 8 mmlong
¯ range: Carpathians and mountains of Balkan
peninsula
Taxon 7: vat. orphanideum (Boiss.) Boiss. [ssp. orphanideum (Boiss.) D.E. Coombe]
¯ flowers pale pink and heads of < 12 flowers
¯ petioles glabrous, leaflets mostly 3 to 7 mmlong
¯ range: Sicily to Asia Minor
J. Agron.Educ., Vol. 20, no. 2, 1991 145
Taxon 8: var. repens L.
• flowers white to pale pink, heads mostly 15 to 25
mm diam.
• petioles mostly glabrous, leaflets mostly 10 to 30 mm
long
• range: temperate zones worldwide
Taxon 8b: var. repens f. hollandicum Erith ex Jav. & Soo
• similar to Taxon 8 but with slightly larger leaflets
(up to 35 mm long) and longer petioles (up to 250
mm long)
• range: spontaneous in agriculture of the Netherlands,
now worldwide
The above classification of the infraspecific ranks of
white clover may be altered in the future as more is
learned about ploidy level and hybridization of the various taxa.
APPENDIX III
Synonymy for Cultivated Groups of White Clover
At present, all cultivars of white clover appear to have
been derived from three taxa (2, 8, and 8b of Appendix
II) and their hybrids. The following list illustrates the
name-and-year method of citation used to show priority
and history. Annotations include Latin abbreviations
used by taxonomists to indicate the status of a name.
Within each of the three main taxa, names are grouped
by rank since priority applies within a rank.
Trifolium repens L. 1753. (See Zohary and Heller [28]
and Szabo [25] for a list of synonyms at the species
level.)
ssp. repens L. 1753.
A.I. typicum Aschers. & Graebn. 1908. (Ascherson and
Graebner's rank is ambiguous.)
var. repens L. 1753.
var. silvestre Alef. 1866. (Also spelled sylvestre and sylvestrel.)
var. typicum Fiori & Paol. 1900. p.p. ssp. prostration
Nym. 1878.
var. typicum (Aschers. & Graebn.) Gams in Hegi 1923
non Fiori & Paol. 1900.
A.I.a. 1.0.7. genuinum Aschers. & Graebn. 1908.
(Ascherson and Graebner's "outlined" rank is ambiguous.)
var. repens f. repens L. 1753. ("Wild" white clover.)
var. microphyllum Lagr.-Foss. 1847. (Erith [8] concluded var. microphyllum was simply a depauperate state.)
f. genuinum (Aschers. & Graebn.) Gams in Hegi 1923,
p.p. f. hollandicum Erith ex Jav. & Soo 1951.
f. silvestre (Alef.) Gams in Hegi 1923, pro syn. of
above.
f. microphyllum (Lagr.-Foss.) Gams in Hegi 1923. (See
var. microphyllum above.)
convar. arcto-alpinum Szabo 1988. (A subgroup of
small, cultivated white clovers.)
convar. nanum Szabo 1988. (Another subgroup of
small, cultivated white clovers.)
146
J. Agron. Educ., Vol. 20, no. 2, 1991
var. repens f. hollandicum Erith ex Jav. & Soo 1951
("Dutch" white clover.)
var. cultum Alef. 1866, p.p. var. giganteum Lagr.Foss. 1847.
var. vulgare, s. auct. 1953, in Hartwig (16).
var. hollandicum, s. auct. 1987, in W.M. Williams (27).
f. genuinum (Aschers. & Graebn.) Gams in Hegi 1923,
p.p. f. repens.
f. silvestre (Alef.) Gams in Hegi 1923, pro syn. of
above.
race hollandicum Erith 1924.
convar. hollandicum (Erith) Szabo 1988.
provar. praecox Szabo 1988. (A subset of convar. hollandicum above.)
provar. prolificum Szabo 1988. (Another subset of convar. hollandicum above.)
var. giganteum Lagr.-Foss. 1847. ("Ladino" white
clover.)
ssp. giganteum (Lagr.-Foss.) Ponert 1973.
var. cultum Alef. 1866, p.p. var. repens f. hollandicum Erith ex Jav. & Soo 1951.
var. latum, auct. Amer., s. auct. et nom. nud. 1894,
in McCarthy and Emery (20). (Also spelled latus and
lata.)
f. giganteum (Lagr.-Foss.) Gams in Hegi 1923.
f. lodigense hort. Gams in Hegi 1923, pro syn. of
above.
f. cultum (Alef.) Gams in Hegi 1923, pro syn. of above.
race giganteum (Lagr.-Foss.) Erith 1924.
convar. giganteum (Lagr.-Foss.) Szabo 1988.
provar. bienne Szabo 1988. (A subset of convar.
giganteum above.)
provar. perenne Szabo 1988. (Another subset of convar. giganteum above.)
12. Gillett, J.M. 1985. Taxonomy and morphology, p. 7-69. In N.L.
Taylor (ed.) Clover science and technology. Agron. Monogr. 25.
ASA, CSSA, and SSSA, Madison, WI.
13. Gray Herbarium of Harvard University. 1968-1986. Gray herbarium index. Harvard Univ. Herbaria, Cambridge, MA.
14. Greuter, W. (ed.). 1988. International code of botanical nomenclature. Koeltz Scientific Books, Konigstein.
15. Greuter, W., H.M. Burdet, and G. Long. 1989. Trifolium repens.
Med-Checklist 4:189-190.
16. Hartwig, H.B. 1953. Legume culture and picture identification.
M.S. Hartwig, Ithaca, NY.
17. Javorka, S., and R. Soo. 1951. A Magyar nOvenyvilag kezikOnyve.
Akademiai Kiado, Budapest.
18. Jeffrey, C. 1990. Biological nomenclature. 3rd ed. Edward Arnold,
London.
19. Lagreze-Fossat, A. 1847. Flore de Tarn et Garonne. Rethore, Mountauban.
20. McCarthy, G., and F.E. Emery. 1894. Some leguminous crops and
21.
22.
23.
24.
25.
26.
27.
28.
their economic value. Bull. North Carolina Agric. Exp. Stn.
98:133-170.
Presl, K.B. 1830. Symbolae Botanicae 1:47.
Royal Botanic Garden at Kew. 1893-1987. Index Kewensis. Clarendon Press, Oxford.
Royal Botanic Garden at Kew. 1980. Draft index of abbreviations.
Her Majesties Stationary Office, London.
Stafleu, F.A., and R.S. Cowan. 1976-1989. Taxonomic literature.
2nd ed. Bonn, Scheltema, and Holkema, Utrecht.
Szabo, A.T. 1988. The white clover (Trifolium repens L.) gene pool.
I. Taxonomical review and proposals. Acta Bot. Hung. 34:225-241.
von Steven, C. 1856. Verzeichniss der auf der taurischen Halbinsel wildwachsenden Pflanzen. Bull. Soc. Imp. Nat. Moscou
29(3):121-186.
Williams, W.M. 1987. White clover taxonomy and biosystematics. p. 323-342. In M.J. Baker and W.M. Williams (ed.) White
clover. C.A.B. International, Wallingford, Oxon, UK.
Zohary, M., and D. Heller. 1984. The genus Trifolium. Israel
Academy of Science and Humanities, Jerusalem.