Bot. J. Linn. Soc., 67: 347-359
December 1973
Chemotaxonomy of Geranium
E. IC. BATE-SMITH
Agricultural Research Council Institute of Animal Physiology, Babraham,
Cambridge
Accepted f o r publication February 1973
The species of Geranium show a wide range of flavonoid pattern, from o n e in which all t h e
regular (primitive) constituents are present t o one where only quercetin and kaempferol are
present. The primitive pattern predominates in th e central Eurasian area, radiating eastward and
westward from which th e flavonoid constituents become progressivley impoverished. A
“flavonoid score” providing a numerical estimate of this impoverishment is proposed. Th e
results are presented and discussed in relation to Knuth’s arrangement of t h e genus.
CONTENTS
Introduction
. . . . . . . . . . . . . . . . . . . . . .
Broad taxonomic implicationsof theflavonoid pattern
. . . . . . . .
Distribution of th e leucoanthocyanidins (LA)
. . . . . . . . . . .
. . . . . . . . . . . . . . . . .
The trihydroxy flavonoids
. . . . . . . . . . . . . . . . . . . . .
The flavonols
Variation in the ellagitannin content
. . . . . . . . . . . . . .
Chromosome number, flavonoid score and geographical location
. . . . . .
. . . . . . . . . . . . . . . .
Other genera of Geraniaceae
. . . . . . . . . . . . . . . . . . . .
Acknowledgements
. . . . . . . . . . . . . . . . . . . . . .
References
347
. 348
. 349
. 3 54
.
.
.
354
355
3 56
35’3
359
359
INTR ODUCT ION
Indications of a correlation between the geographical distribution of a genus
and the phenolic patterns of its species were first encountered in Iris and
Crocits (Bate-Smith, 1968). In the case of Crociis it was observed that “with
few exceptions the species with high sinapic acid have their habitats in the
western, and those with low sinapic acid in the eastern halves of the range of
distribution of the genus”; and in the case of one of the sections of Iris the
distribution of the glycoxanthone mangiferin and certain of the flavonoid
constituents suggested that “it is tempting to consider a process of evolution
and dispersal of an ancestral prototype from a central Eurasian point of origin
eastwards t o the Pacific coast and westwards, after acquiring mangiferin, t o the
east coast of North America”.
The opportunity has been taken of the availability of numerous Geranium
species collected by P. F. Yeo as material for a taxonomic study of the genus
347
348
E. C. BATE-SMITH
(Yeo, 1973), to survey the phenolic constituents and analyse the results from a
geographical standpoint. The genus is very uniform as regards these constituents, differences between species being mainly in regard to the presence or
absence of myricetin, leucodelphinidin and leucocyanidin. Gallic acid, hexahydroxydiphenic acid (present as ellagic acid in acid hydrolysates and recorded
as such), pcoumaric and caffeic acids, quercetin and kaempferol are present in
almost every species, but not in the same absolute or relative amounts; and it is
the relative amounts especially of quercetin and kaempferol in particular
species which have been found to provide a most useful correlation with
habitat. Some data on the ellagitannin content have already been published
(Bate-Smith, 1972) and these show a decreased level in certain species
associated with the presence of a substance with closely similar properties and
also (as reported here) with the presence of glycoflavones. These results will be
considered here along with those reported in Tables 1 and 2, which are
concerned with the distribution of the leucoanthocyanidins and flavonols in
the leaves of 60 species.
The arrangement of the species is based on the latest monograph of the
genus, that of Kunth (1912). In his treatment, Knuth divided the 259 species
he recognized into 30 sections. He gave a good deal of consideration to
geographical distribution; many of his sections have, indeed, a geographical
connotation, and all of them having their range indicated, under broad
headings, in his key. These headings have been taken as a basis for the
presentation of the results in the tables. The easterly and westerly limits of the
ranges of the individual species are taken from his text.
The data for the flavonoid constituents were obtained by paper chromatography of hydrolysates of the leaves, using methods described previously
(Bate-Smith, 1962, and elsewhere), their concentration, judged by the area and
intensity of the fluorescence of the spots, being indicated by the symbols + t o
(+). Except for the presence in certain species of constituents tentatively
identified as glycoflavones (e.g. vitexin and saponaretin), there were no
indications that any other flavonoids were present in the genus. Reduced
flavonoids such as flavones and flavanones, 0-methylated flavonols and
coumarins, which are often helpful in identifying groups of related species,
appeared to be completely absent. Qualitatively, the main differences were in
respect of the presence or absence of myricetin (M), leucodelphinidin (LD) and
leucocyanidin (LCy).
BROAD TAXONOMIC IMPLICATIONS O F THE FLAVONOID PATTERN
Yeo (1973) has concluded that “there appear to be no basic characters that
will enable us t o break the genus up into subgenera”. His own results suggest a
close relationship between sections Ruberta (Robertiana) and Anemonifolia
and between these and G. lucidum (section Lucida) and G. cataractarum
(section Unguiculata), widely separated in Knuth’s arrangement but all with
their habitats in (or at least including) the extreme west of the Eurasian range
of the genus. Their flavonoid patterns are practically identichl.
I t has been suggested (Bate-Smith, 1962; Harborne, 1967) that the
evolutionary trend in the pattern of the flavonoid constituents is from a more
hydroxylated to a less hydroxylated condition (myricetin +. quercetin/
CHEMOTAXONOMY OF GERANIUM
349
kaempferol; leucodelphinidin + leucocyanidin) ar.d from presence to absence
of leucoanthocyanidins. Kubitzki (1968) has adopted and extended this
concept. If the data in Tables 1 and 2 are considered from this point of view,
most of the geographical areas recognized by Knuth can be seen t o contain
representatives which are, in this respect “primitive” and others “advanced”. I t
should be worthwhile to analyse the situation further for each species in terms
of an estimated degree of advancement in relation to its geographical location.
This can be done by allocating marks for the presence of particular constituents
and for the preponderance of the more hydroxylated flavonol quercetin over
the less hydroxylated kaempferol. In this way a “flavonoid score” can be
calculated and the evolutionary status (in this respect) of the individual species
evaluated.
This has been done in the tables under the heading “flavonoid score”, arrived
at by scoring one mark for the presence of trihydroxy groups (myricetin or
leucodelphinidin), one for the presence of leucoanthocyanidin (LD of LCy),
one for the preponderance of quercetin over kaempferol, and minus one for the
emverse situatkm. W& the help of this sous a b r d view can be formed of
the evolutionary status of any suggested grouping together of species.
Considering, for instance, Knuth’s geographical regions, the average scores are
as follows: Palaeoarctic 1.5, Eurasian 0.9, Mediterranean 0.5, Macaronesian 0.3.
The corresponding value for the South and Central American species,
considered as a whole, is 1.0. By and large, these values support Yeo’s view
(1972) that “the genus is best developed in the central and mountainous
regions of large continental land masses, especially of Asia-the fringe groups,
not only morphologically, cytologically and phytochemically, but geographically and ecologically, being found on the southern and western borders of Asia
and Europe”. I t is interesting to note, therefore, that the species extending
west of 2 0 ” E have an average score of 0.78, whilst those within the range
20”-60” E average 1.0 and those east of 80” again average only 0.8.
The species included in each of these averages fall within a considerable
number of Knuth’s sections and are, therefore, very diverse in respect of many
of the characters involved in Knuth’s division of the genus. It is necessary
therefore, next to consider the distribution of particular flavonoids within the
different sections.
DISTRIBUTION OF THE LEUCOANTHOCYANIDINS (LA)
I t is important to recognize that many of those species which possess
persistent rootstocks are known t o have a high concentration of tannin in those
organs (Hegnauer, 1966). In all such species as we have examined, a
considerable amount of that tannin consists of LA. The absence of these from
the leaves does not, therefore, imply an absence of the ability of the plant to
synthesize them (as is the case, for instance, in most of the herbaceous
Sympetalae), but a suppression of (or failure to develop) that ability in the
aerial parts of the plant. This is, however, constantly observed in the
herbaceous members of mainly woody families, such as the Rosaceae and
Leguminosae, and seems likely to be a concomitant of the reduction of such
plants from the arboreal to the herbaceous habit. In Geranium LA is present in
quantity in the leaves of some perennial species only, but it seems to be present
25
Western limit
Geographical range
Eastern limit
M
polyanthes Edgw.
& Ho0k.f.
dahuricum DC.
farreri Stapf.
pylzowianum Maxim.
sanguineum L.
soboliferum Komarov
albanum M. Bieb.
asphodeloides Burmf. Tyrol
pyrenaicum Burm.f.
Morocco
collinum Stephan ex.
Willd.
Caucasus
meeboldii Briq. (syn.
grandiflorum Edgw.)endressii J . Gay
palustre L.
Pyrenees
yunnanense Franch.
-
1 5 . Sanguinea
19. Pyrenaica
2 3 . Palustria
Spain
Manchuria
-
-
Dahuria
-
-
Russia
-
S.W. China
-
Sinkiang
N.W. Himalaya
W. Pyrenees
-
-
Pontus
Caucasus
-
Caucasus
N. Korea
-
-
Japan
E. Armenia
-
-
China
China
-
C. Himalaya
-
Madeira
-
14. Polyan tha
N. Persia
Japan
-
S. Persia
W.Himalaya
-
-
Macaronesia
E.N. America
purpureum Vill.
robertianum L.
rubescens Yeo
3 . Robertiana
Macaronesia
Eritrea
lucidum L.
m.lophum Boiss.
0
TEMPERATE EURASIAN
bohemicum L.
Morocco
Asia Minor
(lanuginosum Lam., syn. of bohemicum and indistinguishable therefrom . . . . . . .
columbinum L.
Portugal
Siberia
+
Persia
dissectum L.
Mediterranean
divaricatum Ehrh.
Mediterranean
Outer Moneolia molle L.
Morocco
W.Himalaya
pusillum Burm.f.
Spain
W. Himalaya
rotundifolium L.
Mediterranean W. Himalaya
tewanum A. Heller
? introduced (cf. dissectum)
Species
2. Lucida
1 . Colum bina
Section
D
1
++
+++
1
2
1
1
+
(+)
0
0
(+)
+
1
0
1
+++
(+)
++
+
1
2
1
2
++
++
++
0
0
0
0
-1
2
1
0
1
1
-1
1
2
(+)
Score
++
+
+
+
(+)
(+)
+
(+)
++
++
++
++
++
++
K
26,28
28
28
28
28
22-24, 26, 28
28
28
56,84?
28
32.64
20
26
26
26. 34?
26
28
48)
18
22
Chromosome number (2n)
. . . . . . . . . . . . ......................
Flavonoids
Q
Cy
Table 1. Old World and North American species of Geranium (fresh material except where stated)
7. Su bacaulia
ca tarac tarum Cosson
dalmaticum Beck
macrorrhizum L.
6. Unguiculata
argenteum L.
cinereurn Cav.
d o ‘Bevan’s var.’
phaeum L.
reflexum L.
sinense K. Knuth
atlanticum Boiss.
gymnocaulon DC.
ibericum Cav.
platypetalum Fischer
& Meyer
psilostemon Ledeb.
renardii Trautv.
aconitifolium L’Her.
(syn. rivulare Vill.)
maculatum L.
oreganum Howell (syn.
incisum Nutt.)
richardsonii Fischer
& Trautv.
sylvaticum L.
viscosissimum Fischer
& Meyer
pratense L.
nodosum L.
versicolor L.
wallichianum D. Don
wilfordii Maxim.
13.Reflexa
111. Recurvata
11. Eusylvatica
12. Sylvatica
I. Mediterranea
24. Striata
-
Japan
Himalaya
-
-
C. China
-
Western USA
-
Kamchatka
Pyrenees
-
Belgium
-
Alps and Appenines S. Alps
MEDITERRANEAN
Spain
Dalmatia
Greece
PALAEOARCTIC AND MEDITERRANEAN
Pyrenees
W. Russia
Italy
Greece
Central China
-
-
-
-
(+)
1
1
1
1
++
++
++
0
-1
1
2
1
2
1
+
(+)
++
++
+
++
++
+
0
1
Siberia
+
++
-
Western USA
0
++
Western USA
0-1
1
++
1
2-3
3
++
++
1
1
2
3
2
-1
-1
++
++
++
(+)
(+)
+
++
+
++
-
-
-
-
+
Swiss Alps
Eastern USA
Armenia
Armenia
W. Caucasus
Algeria
Armenia
Armenia
PALAEOARCTIC
Greece
Caucasus
-
Pyrenees
Italy
28
28
46
36
14.28
28
28
28
28
28
28
28,42
28,56
56
28
28
28
28
-
AUSTRALASIA
Chatham I.
traversii Hook.
18.Australiensia
* Cambridge University Herbarium material.
30. Neurophyllodes arboreum A. Gray
cuneatum Hook.
++
-
HAWAII*
S. AFRICA
-
(+)
++
-
++
-
-
(+)
-
+
+
(+)
-
+++
+
-
(+)
(+A
+
-
K
+
+
Flavonoids
Q
Cy
-
-
+
-
Natal
-
-
D
-
incanum Burm.f.
all Macaronesia
MACARONESIA
21.Incana
M
canariense Reuter
madarense Ye0
palmatum Cav.
Geographical range
Eastern limit
9. Anemonifolia
Western limit
Species
Section
Table 1-(Continued)
+
-1
1
1
3
1
0-1
0
Score
28
128
68
68
Chromosome number ( 2 n )
Mendoza, Chile
Tracey 105, Colombia
Cuatrocasas 2273, Colombia
Pringle 10021, Hidalgo, Mexico
Scott Gentry 2756, Mexico
Mexia 2676, Mexico
Balls & Gourlay B5203, Mexico
Balls 4638, Guatemala
Grubb er al., 236, Colombia
Grubb e t al., 6 2 3 , Ecuador
Lehmann 4 8 1 1 , Colombia
Bolivia
Chile
Peru
Argentina
Chile, Argentina, Patagonia
S.E. Australia
Chile, Argentina
Peru, Bolivia, Chile, Argentina,
New Zealand
Venezuela
Venezuela, Colombia
Mexico
Mexico
Mexico
Mexico
Guatemala
Tropical Andes
Peru, Ecuador
Peru, Ecuador, Colombia
sessilifrorum Steud.
lindenianum Turcz.
multiceps Turcz.
bellum Rose
niveum S . Wats.
potentillaefolium DC.
schiedianum Schlechtd.
andicola R. Knuth
agavacense Willd. ex Kunth
?diffusum Kunth
sodiroanum R. Knuth
5 . Andina
1 1 . Gracilia
2 2 . Incanoidea
2 9 . Diffusa
-
+
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
+
Sellow, Brazil
Pedersen 63 1 3 , Argentina
Badcock 541, Bolivia
Hohenacker 259, Valdivia
Worth 9117, Lima, Peru
Koslawsky 7 1 , Argentina
Mexia 7991, Chile
E. L. Green, California
Weidemann 60. Chile
Brazil, Uruguay, Paraguay
albicans St. Hil.
albicuns S t. Hil.
fiebrigianum R. Knuth
intermedium Colla
limae R. Knuth
magellanicum H0ok.f.
patagonicum Ho0k.f.
retrorsum L’n6r.
submolle R . Knuth
4. Chilensin
-
D
M
Provenance
Distribution
Species
Section
++
+
++
(+)
+++
-
(+)
-
-
(+)
+
-
+
++
++
+
++
+
+
?
++
(+)
(+)
-
-
-
-
-
-
1
1
-1
1
1
1-2
1
1
2
1
1
1
0
1
1
-1
1
1
Score
y K
___~
2
1
(+)
-
C
+++
++
++
++
+
++
++
++
+
(+)
Q
Table 2. Central and South American species of Geranium (Kew Herbarium material)
3 54
E. C. BATE-SMITH
in amounts too small to be visible on chromatograms in many species. It is
difficult to be certain of this, however, because of the anthocyanin pigment in
the leaves of so many geraniums, sometimes in patches, often on the petiole
and extending up the midrib. In the tables, only those species giving
anthocyanidin spots definitely derived from LA are recorded as positive for
LA.
The presence of LA is associated with the characters of perennial habit and
more or less woody rootstock; but since the species not having these characters
are restricted in distribution to temperate areas, the correlation with range is
still a valid one. The exceptionally high flavonoid scores for some of the species
in sections Sylvatica, Striata and Incana are due to this contribution of LA t o
the score.
THE TRIHYDROXY FLAVONOIDS
The absence from the leaves of a plant of the trihydroxyflavonoids myricetin
(M) and leucodelphinidin (LD) is currently considered to be associated with
evolutionary advancement in vascular plants, not necessarily associated with
the herbaceous or woody habit of the plant, but as a feature of the family to
which it belongs (Bate-Smith, 1962). In this respect, therefore, the Geraniaceae
rate as a rather primitive family, the individual species showing a gradation
from primitive to advanced insofar as these constituents are present or absent.
Of the two constituents, M is the more indicative, because LD may fail to be
produced, along with LCy, as a consequence of the total loss of LA.
Geographically, M extends westward into Spain and Portugal in G.
columbinum and G. sanguineurn, both extending eastwards into Russia; in G.
endressii, endemic in the Pyrenees; and in G. nodosum, which occurs from the
Pyrenees to Greece. G. viscosissimum is limited to western U.S.A. G.
dahuricum in Eastern Asia and G. incanum in South Africa are especially rich
in M.
The South American species which contain M are interesting because one of
them, G. albicans, gave divergent results for the two specimens examined.
These were rechecked by the Kew Herbarium and confirmed as correctly
determined. The one collected in Brazil had M, the other, collected in
Argentina, had none. A similar situation has been encountered in other genera
(Ulmus (Bate-Smith & Richens, unpubl.) and Eucalyptus (Hillis, 1966)), and it
suggests that, in the present environments of these plants, the possession of
trihydroxyflavonoids is no longer needed for survival (with the implication
that, in the environments from which they emerged, their presence was
necessary). This is an important consideration in any discussion of the origin of
the Geraniaceae and other families with similar characteristics of range and
chemistry.
T H E FLAVONOLS
The idea of using the degree of hydroxylation of the B ring of the flavonoid
molecule as an index of evolutionary advance was first put forward by Kubitzki
(1968), who applied the concept especially to the case of Dillenia. He
considered the sequence myricetin +quercetin + kaempferol to be one of
CHEMOTAXONOMY OF GERANIffM
355
continuously diminishing hydroxylation capacity, but we ourselves regard this
to be true only in the case of quercetin +. kaempferol; introduction of the
third, vicinal hydroxyl group is a step of an altogether different kind from that
of the orthohydroxylation of a monohydroxy phenol, probably lost in a single
step by a single-gene mutation. The idea as regards quercetin -+ kaempferol
does, however, seem to be borne out by Kubitzki’s own results, and by
numerous other instances, one of which is the present instance of Geranium.
In view of the ease with which an orthohydroxyl group can be added by
enzyme action to one preexisting in a benzene ring, it might be expected that
the relative amounts of monohydroxy and orthodihydroxy phenolic compounds in plant tissues would be readily susceptible to variation under varying
physiological conditions but this does not seem to be the case. Each species
carries its own characteristic proportion of quercetin to kaempferol, the results
for each species being generally reproducible from one individual to another
(but the same is not true of myricetin). Also, closely similar species (e.g. those
in section Robertiana) agree with one another in the proportions of their mono
to dihydroxy constituents. Actually, in Germium there are very few species in
which quercetin is equal to or less than kaempferol, and it is almost true t o say
that the genus is characteristically one in which quercetin is the predominant
flavonol.
It is necessary, however, to take into account another constituent present in
a number of species, not at present unambiguously identified but agreeing in its
behaviour with a glycoflavone, probably a glycoapigenin. If so, this should be
added to the score for kaempferol, since there is reason to believe (Bate-Smith,
1965) that it is in some plants a biosynthetic equivalent of this flavonol. It is
most conspicuously present in G‘. reflexurn but it is also present in the nearly
related G. phaeum and G. aristatum, and a similar, if not the same, substance is
present in G. rnolle and G. rotundifolium. Its distribution thus appears to
follow rather closely that of the “phaeum-reflexurn” factor (see below).
VARIATION IN THE ELLAGITANNIN CONTENT
The ellagitannin (i.e. hexahydroxydiphenyl glucose (HHDPG) ester) content
of the leaves of 27 species of Geranium has been the subject of a recent
communication (Bate-Smith, 1972). The amount varies between 1 and 20% of
the dry weight, the larger amounts occurring in species, such as those in section
Sylvatica, which have the highest flavonoid scores, and smaller amounts not
only in sections with low flavonoid scores, such as Columbina, Lucida and
Robertiuna, but also in sections Reflexa, Palustria and Stricta. In many of the
species with low ellagitannin contents, in addition t o HHDPG, which reacts
with nitrous acid to give a blue product with absorption at 600 nm, there is
present a constituent which gives a red product absorbing at 530 nm. It is very
probable that this is an 0-glycoside of HHDPG, because ellagic acid is the only
product to which it could give rise which can be seen on chromatograms of acid
hydrolysates. This probability is strengthened by the fact that it is not always
present in G. phaeum. It is present in the specimen of var. phaeum growing in
the Cambridge University Botanic Garden, but not in var. lividum growing both
there and at Kew; nor is it present in a wild form growing in the vicinity of
Cambridge. I t is, however, present in two specimens of G. reflexum, one
356
E. C. BATE-SMITH
growing at Cambridge and one at Kew, and in the Kew specimen of G.
uristatum. The amount of 600 mm absorption is always lower in those forms
which have the 530 mm absorption, but it is impossible to compare the overall
content of the precursors because the extinction coefficient of the 53Onm
product will not be known until its precursor has been isolated. By and large, it
seems likely that there is a fairly constant amount of the common precursor in
the three species and the forms of G. phaeum. At the most, however, this is
only about a third of that present in the majority of Geranium species.
A 5 3 0 nm precursor is also present in G. dissectum, G. molle, G.
rotzindifolium, G. endressii and G. nodosum. It is interesting to note that the
ranges of all of these species extend into south-west Europe, so that this does
seem to be a character in some way correlated with the westward migration of
species.
Most of the species with the 530 mm constituent also contain the
glycoflavone mentioned in the preceding section. This strengthens the
possibility that the phaeum-reflexum factor is a glycoside of HHDPG, since
glycosidation would then be a common feature of both these constituents.
CHROMOSOME NUMBER, FLAVONOID SCORE AND GEOGRAPHICAL LOCATION
It has already been observed (Bate-Smith, 1972) that those species with
chromosome numbers lower than 2n = 28 (the commonest number in the
genus) are also those with low ellagitannin content. These are also species with
low flavonoid scores, whose ranges extend into south-west Europe. Scrutiny of
the chromosome numbers in the right-hand column of Table 1 shows that only
5 of the 18 species occurring in European localities west of Greenwich (of
which the chromosome numbers are known) have the regular number of
2n = 28, the remainder, with the exception of G. cataractarum and Macaronesian species, all having fewer. In these species, therefore, westward migration
seems to be associated with decrease in chromosome number, with loss of
complexity and diversity i n .the flavonoid constituents, and with decrease in
ellagitannin content. This conclusion is strongly supported by Yeo’s (1973)
observation (based on Table 1 ) that those species described in Flora Eitropaea
with the carpel-projection type of seed-dispersal have lower flavonoid
scores (average 0.1) than those with seed-ejection (average 1.3 3 ) or Erodiumtype fruits (average 1.0). The first are morphologically, cytologically, geographically and ecologically fringe groups of the south and west borders of Asia and
Europe in semi-arid, ruderal or rocky habitats.
In the Southern Hemisphere the data are not sufficient t o make a
comparable statement. The flavonoid score of the South African species G.
incanum is maximal, indicating the least possible change from the hypothetical
primitive condition. The South American species are as diversified in their
flavonoid patterns as those of the Northern Hemisphere, but without
chromosome numbers a similar analysis of migratory trends cannot be
attempted. I t seems likely, however, that the South American species
originated from several different sources: from a common source with the
South African species; from North-west America along the mountain chain; and
from Northeast America by way of the Caribbean. The higher flavonoid scores
should be found in the first group and the lowest ones in the last.
CHEMOTAXONOMY OF GERANIUM
357
Whatever their origin, the species in the Pacific Islands and Australasia must
have had long migratory routes, and the few species included in the present
survey have, accordingly, low flavonoid scores. It is interesting that, of the
Hawaian species, G. arboreum, the most woody of all Geranium species, has
nevertheless an exceptionally low flavonoid score, whereas G. cuneaturn, with
exceptionally atypical foliar morphology, has an average score. It is unfortunate that the chromosome numbers of these are not in the record.
Some help in the further understanding of the significance of these data is
afforded by the situation found in other genera of the Geraniaceae, and a
limited survey of these genera follows.
OTHER GENERA OF T H E GERANIACEAE
These have not been covered so extensively as Geranium, and most of the
results have been obtained with herbarium specimens. For this reason the data
will be dealt with only in summary from here. The main features are recorded
in Table 3 .
Knuth includes the first four genera with Geranium in his tribe Geranieae.
Erodium has a similar range t o Geranium, but is more strongly represented in
North Africa and the Mediterranean. With the exception of the single South
African species, E. incarnatum, these are the only species that have been
available for examination. They have an even lower flavonoid score than the
geraniums in this area, and fewer than half the species have any ellagic acid.
The basic chromosome number ( 2 n = 20) suggests that, as in Geranium, the low
flavonoid score is associated with a reduction in chromosome number.
The single South African species, the chromosome number of which is
unfortunately not in the record, has a fuller complement of flavonoids.
None of the New World species has been examined.
Monsonia has a more southerly African distribution, with one species, M.
senegalensis, extending into India. All the species have ellagitannin, but the
flavonoid scores are similar to those of Erodium. The two South African
species, however, have additional, unidentified flavonoid constituents.
The basic chromosome number (211 = 2 4 ) is slightly higher than that of
Erodium.
Sarcocaulon and (except for two species in Turkey and Iraq) Pelargonium
are confined to South Africa. Both have 2 n = 22 as the basic chromosome
number, but Sarcocaulon hurmannii, as well as some Pelargonium species, has
the tetraploid 2n = 4.4. This species, and most pelargoniums, have flavonoid
patterns like Monsonia, but some species, especially in sections Hoarea and
Pelargium, have exceptionally high flavonoid scores. Both these sections are
stongly represented in the South-west Cape Province, which is clearly to be
identified as the “epicentre” of the genus; but the data are insufficient to
support an analysis therefrom of the effects of distribution on the flavonoid
pat tern.
It can surely be no coincidence that the single South African species of
Geranium, the single South African species of Erodium and the species
occupying a central position in the distribution of Pelargonium all have the
highest flavonoid scores of their respective genera. This would seem t o indicate
an origin from a common ancestor which, because of the present range of the
1
1
10
2
1
1
1
1
6
>227
5
1
3
6
28
1
Sarcocaulon
Pelargonium
Biebersteinia
R hyncotheca
Wendtia
Balbisia
Viviania
Dirachma
5
29
Monsonia
44
22
No record
No record
No record
18 (1 record)
No record
No record
Much reduced
Primitive
Somewhat reduced
Like Monsonia
Extremely variable
Quite atypical
Advanced
Somewhat advanced
Somewhat advanced
Advanced
Like Geranium sect.
Ruberta
-1 to 1
2
1
1
-1 to 3
-1 to 1
0
0
1
0
1
20
No record
2 4 (1 record)
Flavonoid features
6 Mediterranean
1 S. African
Tropical and S. Africa
1 locality in India
S. Africa
S. Africa
Central and W. Asia
Tropical Andes
S. America
Subtropical Andes
S. America
Socotra
7
60
Basic chromosome
number of genus
Flavonoid
score
No. of species Geographical range of
examined
species examined
Erodium
Genus
No. of species
in genus
Table 3 . Other genera of Geraniaceae
1
1
1
1
0
1
1
10
5
0
3
No. of species with
Ellagitannin
present
CHEMOTAXONOMY O F GERANIUM
3 59
Geranieae in Eurasia and Africa, could only have been in a land mass to the
south of the present Asian continent.
Biebersteinia has a completely different flavonoid pattern from any other
genus of the Geraniaceae. B. multifida has none of the regular flavonoids, but a
number of unusual and unidentified flavonoid constituents. B. odora (syn. B.
enzodi) has M, LD and LCy, together with the same unusual flavonoids as B.
multifida. Takhtajan (1969) makes a separate family for this genus, which this
evidence would help t o justify; but Corner (pers. comm.) finds that the
seedcoat structure is quite consistent with its inclusion in Geraniaceae.
Dirachma, endemic in Socotra, has a typical Geranium flavonoid pattern.
The South American species, placed in five genera, have for the most part
low flavonoid scores. Since there is only one chromosome count for dl'five
genera in the record, there are insufficient data for a comparable analysis of the
cytological and chemical characters to be possible at the present time. Such as
they are, however, the data suggest a relatively recent, common origin for these
genera.
ACKNOWLEDGEMENTS
The author wishes to acknowledge with gratitude the help of the Director
and Dr P. F. Yeo of the Cambridge University Botanic Garden and the
Director, Royal Botanic Gardens, Kew for supplying and identifying botanical
material; and to thank Dr Yeo for taxonomic advice and helpful criticism.
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