Plant Syst. Evol. 246: 163–175 (2004)
DOI 10.1007/s00606-004-0154-y
Molecular phylogenetics of Dipsacaceae reveals parallel trends
in seed dispersal syndromes
P. Caputo, S. Cozzolino, and A. Moretti
Dipartimento di Biologia vegetale, Università degli studi di Napoli Federico II, Napoli, Italy
Received January 22, 2002; accepted February 22, 2004
Published online: July 13, 2004
Ó Springer-Verlag 2004
Abstract. Phylogenetic relationships among 17
taxa of Dipsacaceae were inferred from nucleotide sequence variation in both the internal
transcribed spacer (ITS) regions of nuclear ribo(UAA)
somal DNA and the chloroplast trnL
intron
sequences. The combined phylogenetic analysis,
carried out by using two taxa from Valerianaceae
as an outgroup yielded a single most parsimonious tree, in which Dipsacaceae are divided into
two major clades: one including Lomelosia and
Pycnocomon, both in a sister group relationship
with a clade containing Pterocephalus, Scabiosa
and Sixalix; the other including Pseudoscabiosa,
Succisa and Succisella is sister group to Knautia,
Pterocephalidium, Dipsacus and Cephalaria. The
results obtained here greatly differ from previous
ones based on classical morphology, but are
congruent with recent findings on epicalyx differentiation and with pollen characters. In particular, our results would confirm on molecular
grounds the recently restricted circumscription
for Scabioseae proposed by other authors. Our
phylogenetic hypothesis indicates that adaptations
to seed dispersal have been a very strong driving
force in Dipsacaceae evolution, with similar
selective pressures causing the onset of similar
epicalyx shapes and dispersal modes in a parallel
fashion in various taxa. For this reason, the gross
morphology of the involucel is deceptive in
inferring relationships.
Key words: Dipsacaceae, Scabioseae, phylogeny,
seed dispersal, ITS, trnL.
Dipsacaceae Juss. (Dipsacales Lindley) is a
dicotyledonous family including 12–13 genera
and 250–350 species, depending on circumscription, distributed in Eurasia and Africa,
with the great majority of the taxa mainly
centred around the Mediterranean basin. The
family constitutes a monophyletic group (Ehrendorfer 1964a; Verláque 1977a, 1984a,b;
Caputo and Cozzolino 1994), whose characteristics are represented by an epicalyx, which
encases the fruit and whose shape, symmetry
and ornamentations are taxonomically relevant, and by an involucrate head. The family is
a derived member of the order Dipsacales,
where it is sister group to Valerianaceae
(Backlund and Bremer 1997).
Delimitation of taxa within the family has
always been subject to controversy; consequently, circumscription of genera and tribes
has repeatedly changed over time, because of
the overall morphological similarity among the
taxa in the family and of their diversity in
structural detail. In particular, the classical
concepts of Scabiosa L. s.l. and Pterocephalus
(Vaill.) Adans. s.l. included species which are
164
presently attributed to eight separate genera,
most of which with entirely independent phylogenetic histories.
In fact, genus Scabiosa was traditionally
divided into five sections. After the studies by
Verláque (1984a, 1985a, 1986a, b) and Devesa
(1984a, b), which demonstrated independent
evolutionary histories for its sections, Greuter
and Raus (1985) and Greuter et al. (1986)
designated Lomelosia Rafin. for the species
traditionally belonging to sect. Trochocephalus
Mertens et Koch, Scabiosa s.str. for the species
belonging to sect. Sclerostemma Mertens et
Koch, Sixalix Rafin. for those formerly
belonging to sect. Cyrtostemma Mertens et
Koch, Pseudoscabiosa Devesa for several
archaic species formerly isolated in sect. Asterothrix Font Quer; in the same period the
name Pycnocomon Hoffmanns. et Link was
resumed in order to refer to the atypical species
Scabiosa rutifolia Vahl, formerly placed in
Scabiosa sect. Pycnocomon.
Similarly, the genus Pterocephalus (Vaill.)
Adans., has included in the past various
atypical species which have been recently
segregated in Pycnocomon [Pycnocomon
intermedium (Lag.) Greuter et Burdet ¼
Pterocephalus intermedius (Lag.) Coutinho],
Pterocephalidium G. López [Pterocephalidium
diandrum (Lag.) G. López ¼ Pseudoscabiosa
diandra
Devesa ¼ Pterocephalus
diandrus
(Lag.) Lag.] and Pterocephalodes V. Mayer et
Ehrend. (name adopted for three South-Eastern Asian taxa). As in the case of some of the
taxa formerly lumped in a loose concept of
Scabiosa, the taxa segregated from Pterocephalus are not close to the former genus from a
phylogenetic point of view.
Correspondingly, the hypotheses of tribal
relationships within the family have been
greatly modified during time. The main differences among the various phylogenetic hypotheses produced in the recent past (Ehrendorfer
1964a,b, 1965; Verláque 1977a,b, 1984a,b,
1985a,b, 1986a,b; Caputo and Cozzolino
1994, 1995), consisted in the positions of the
archaic genera Succisa Necker, Succisella Beck
P. Caputo et al.: Molecular phylogeny of Dipsacaceae
and Knautia (L.) Coult. as compared to the
rest of the family and in the relative positions
of the above mentioned segregates of Scabiosa
s.l. However, all the authors listed above
concurred towards the idea that tribe Scabioseae, as traditionally circumscribed (i.e. Lomelosia, Pseudoscabiosa, Pterocephalidium,
Pterocephalus, Pycnocomon, Scabiosa, Sixalix,
Succisa, and Succisella) was monophyletic.
The recent papers by Mayer and Ehrendorfer (1999, 2000) showed that a monophyletic circumscription of Scabioseae should
include less taxa than previously suggested.
The latter authors also indicated that the
homology of parts of the epicalyx, with special
reference to a differentiation of its distal region
(the corona, which is a membranous expansion
in various taxa), has been often misinterpreted,
as a consequence of widespread modifications
in response to adaptative pressures to fruit
dispersal which have fostered rampant homoplasy in both the corona and the calyx.
Therefore, Mayer and Ehrendorfer (1999)
suggested that a monophyletic circumscription
of Scabioseae should include only Lomelosia,
Pterocephalus s.str., Pycnocomon, Scabiosa
s.str. (Scabiosa sect. Scabiosa in their study),
and Sixalix (Scabiosa sect. Cyrtostemma in
their study). This more restricted circumscription of Scabioseae would exclude Pseudoscabiosa, Pterocephalidium, Succisa, Succisella, as
well as Pterocephalodes.
This paper aims at a molecular verification
of the pattern of descent among dipsacaceous
genera, in the light of the aforementioned
uncertainties, also in order to test to which
extent epicalyx and calyx modifications (which
are functional towards seed dispersal) developed homoplasiously. To this purpose, Internal Transcribed Spacer (ITS) regions of nuclear
(UAA)
inribosomal DNA and chloroplast trnL
trons were sequenced for representative taxa
within the family. These sequences were chosen
as they are regarded to have a mutation rate
which makes them suitable for studies of
relationships below the family level (Baldwin
et al. 1995, Gielly and Taberlet 1996).
P. Caputo et al.: Molecular phylogeny of Dipsacaceae
Material and methods
The taxa employed in this study are reported in
Table 1. The selection includes representatives
from all recognized genera of Dipsacaceae with
the exception of Pterocephalodes, Scabiosiopsis
Rech. f., and Tremastelma Rafin. (the latter two
clearly being, however, derived members of genus
Lomelosia). All specimens were either field collected
by the authors or planted from seeds and cultivated
at the Botanical Garden of Naples, Italy. Leaves
were collected at flowering time. Voucher specimens of the examined plants are deposited at NAP.
Total DNA was extracted following either the
procedure described in Caputo et al. (1991) or that
of Doyle and Doyle (1990).
ITS 1 and 2 were amplified by using the
primers described in Aceto et al. (1999). The
(UAA)
chloroplast trnL
intron was amplified using
the two primers reported by Taberlet et al. (1991).
PCR conditions were as described in Aceto et al.
(1999). PCR amplification products were purified
by using Microcon 100 microconcentrators (Amicon, Danvers, MA, U.S.A.) and double-strand
sequenced in both directions by using a modification of the Sanger dideoxy method (Sanger et al.
1977) as implemented in a double strand DNA
cycle sequencing system with fluorescent dyes.
Sequence reactions were then loaded into a 373A
Applied Biosystems Automated DNA sequencer
(Applied Biosystems, Foster City, CA, U.S.).
Sequences were then reduced to the appropriate length by aligning them with various sequences
available in the literature. Six fictitious unknowns
(N’s) were added at the 3’ terminus of ITS1 in all
taxa to prevent terminal misalignments.
Alignments were carried out by using Clustal
W ver. 1.81 (Thompson et al. 1994) with default
settings, except for the parameter TRANSWEIGHT (which controls the transition/transversion ratio), which was set to one and MAXDIV
(which controls the delay of the alignment for the
most divergent sequences), which was set to 80%.
Aligned sequences were then visually inspected
to correct gap distributions devoid of biological
meaning, aiming to reduce the number of gaps. The
complete alignment used for all further analyses is
available upon request to the senior author.
Cladistic analyses were carried out on the ITS
and trnL intron data separately, as well as on a
combined matrix. Three different sets of analyses
were conducted in relation to indel treatment: with
165
indels included in the analyses (scoring gaps as
missing data, dataset A), with equivocal indels (i.e.
indels susceptible of different reconstructions)
excluded (dataset B), and with unequivocal indels
given unit weight (nested indels were scored as
different states of a multistate character, dataset C).
In order to verify to which extent ambiguous
gap positions may influence topology, the elision
approach, described by Wheeler et al. (1995), was
used. This technique consists in ‘‘eliding’’ various
individual alignments into a single combined
alignment on which a phylogenetic analysis is
carried out.
To this aim, six alignments were carried out for
ITS data and for trnL intron data separately. These
alignments were carried out by using Clustal W ver.
1.81 with the same parameters as above, but with
variable gap opening and extension costs at
wide intervals in each alignment (PWGAPOPEN=
GAPOPEN from 10 to 20 and PWGAPEXT=
GAPEXT from 4 to 8). The six alignments obtained
plus the original alignment were combined, for each
dataset, in a single matrix. These elided ITS and
trnL intron matrices were analyzed both separately
and in combination, in this case always scoring gaps
as missing data.
All the manipulations of the matrices, as well
as the cladistic analyses, were carried out by using
using the cladistic software environment Winclada
(Nixon 1999), running Nona (Goloboff 1999) as a
daughter process, with the following parameters:
hold 100000; hold/100; mult*100; max. The resulting cladograms were investigated with Winclada,
which was also used to evaluate congruence
between the ITS and trnL intron matrices according to the ILD test of Farris et al. (1994), to
calculate bootstrap percentages (out of 1000 replicas) and branch support (up to trees 10 steps
longer), as well as to plot morphological characters
onto the tree shown in Fig. 1.
Comparison of sequence substitution rates
between clades was carried out by using the method
of Robinson et al. (1998), as implemented in the
RRTree software (Robinson-Rechavi and Huchon
2000). The following tests were carried out separately for the ITS and trnL intron matrix: the two
major clades resulting from the previous analysis,
the four major clades, all the genera, four groups of
taxa homogeneous in terms of seed dispersal
strategies. Significance threshold was calculated as
0.05/numbers of groups in each test.
166
P. Caputo et al.: Molecular phylogeny of Dipsacaceae
Table 1. Species, length (bp) and Genbank accession nos. of the sequences used in this study. In the
columns labelled ‘‘Genbank accession no.’’, the three values correspond to ITS 1, ITS2 and trnL intron,
respectively
Species
ITS1
length
(bp)
ITS2
length
(bp)
trnL
intron
length (bp)
Genbank
accession
nos.
Cephalaria leucantha (L.) Roem. & Schult.
249
248
513
Cephalaria syriaca (L.) Roem. & Schult.
235
213
512
Dipsacus sylvestris Huds.
223
213
513
Knautia arvensis (L.) Coult.
290
224
526
Lomelosia argentea (L.) Greuter et Burdet
222
228
516
Lomelosia caucasica (MB.) Greuter et Burdet
222
227
519
Pseudoscabiosa limonifolia (Vahl) Devesa
238
230
510
Pterocephalidium diandrum (Lag.) G. López
240
229
523
Pterocephalus perennis Coult.
223
227
547
Pycnocomon rutifolium (Vahl)
Hoffmanns. & Link
227
233
537
Scabiosa africana L.
222
226
537
Scabiosa japonica Miq.
225
227
537
Scabiosa uniseta Savi
223
225
537
Sixalix atropurpurea (L.) Greuter et
Burdet subsp. maritima (L.)
Greuter et Burdet
Sixalix farinosa (Cosson) Greuter et Burdet
224
226
541
223
229
541
AJ426523
AJ426524
AJ427376
AJ426525
AJ426526
AJ427377
AJ426527
AJ426528
AJ427378
AJ426529
AJ426530
AJ427379
AJ426531
AJ426532
AJ427380
AJ426533
AJ426534
AJ427381
AJ426535
AJ426536
AJ427383
AJ426537
AJ426538
AJ427382
AJ426539
AJ426540
AJ427384
AJ426541
AJ426542
AJ427385
AJ426543
AJ426544
AJ427386
AJ426545
AJ426546
AJ427387
AJ426547
AJ426548
AJ427388
AJ426549
AJ426550
AJ427389
AJ426551
P. Caputo et al.: Molecular phylogeny of Dipsacaceae
167
Table 1 (continued)
Species
ITS1
length
(bp)
ITS2
length
(bp)
Succisa pratensis Moench
243
226
512
Succisella inflexa (Kluk) G. Beck
239
220
513
Patrinia intermedia L.
220
224
514
Valeriana officinalis L.
226
237
497
Results
The lengths of the ITS regions and of the trnL
introns for all taxa in study, as well as their
Genbank accession numbers, are reported in
Table 1. ITS1 length ranged from 222 to 290
bp; ITS2 length ranged from 213 to 247 bp;
trnL intron length ranged from 497 to 541 bp.
The combined matrix including all indels
(consensus length 1154 bp, dataset A) produced one most parsimonious cladogram
(length ¼ 775, CI ¼ 0.69, RI ¼ 0.60; by excluding uninformative characters, length ¼ 551,
CI ¼ 0.57, RI ¼ 0.60).
The combined matrix obtained excluding
equivocal indels (consensus length 1042 bp,
dataset B) produced 2 equally parsimonious
cladograms (length ¼ 609, CI ¼ 0.69, RI ¼
0.62; by excluding uninformative characters,
length ¼ 442, CI ¼ 0.57, RI ¼ 0.62).
The combined matrix obtained excluding
equivocal indels and scoring unequivocal indels as multistate characters (consensus length
1042 bp, dataset C) produced 2 equally parsimonious cladograms (length ¼ 656, CI ¼ 0.70,
RI ¼ 0.62; by excluding uninformative characters, length ¼ 470, CI ¼ 0.59, RI ¼ 0.62).
59 (2)
7
(>10)
33
Genbank
accession
nos.
trnL
intron
length
(bp)
AJ426552
AJ427390
AJ426553
AJ426554
AJ427391
AJ426555
AJ426556
AJ427392
AJ426557
AJ426558
AJ427393
AJ426559
AJ426560
AJ427394
Valeriana officinalis
Patrinia intermedia
Pseudoscabiosa limonifolia
95 (10)
22
Succisella inflexa
84 (4)
12
29
7
Succisa pratensis
8
(1)
Knautia arvensis
49
(1)
Pterocephalidium diandrum
5
23
5
Dipsacus sylvestris
88 (6)
14
55 (1)
7
14 Cephalaria leucantha
6
C. syriaca
12
84 (5)
9
37
95(5)
6
92 (6)
8
82 (3)
5
21
Pycnocomon rutifolium
Lomelosia argentea
8
L.
caucasica
8
Pterocephalus perennis
Sixalix atropurpurea
7
Sixalix farinosa
8
Scabiosa japonica
61 (2)
14
Scabiosa africana
95 (7)
5
3
8
Scabiosa uniseta
100 (>10)
22
(3)
77
5
5
Fig. 1. Single maximum parsimony cladogram obtained for the combined data set including all indels
(dataset A). Length ¼ 775, CI ¼ 0.69, RI ¼ 0.60 (by
excluding uninformative characters, length ¼ 551,
CI ¼ 0.57, RI ¼ 0.60). Numbers below branches
represent synapomorphies; numbers above branches
indicate bootstrap percentages above 50% (out of
1000 replicas, rounded to the unit); numbers in
parentheses above branches indicate branch support
(up to 10 steps longer). Support data for the outgroup
are not shown
168
P. Caputo et al.: Molecular phylogeny of Dipsacaceae
Table 2. Consensus length (bp), number of most parsimonious trees, with length, CI’s and RI’s for the
data sets used in this paper. The second row in the datasets contains the values after removal of uninformative characters. Dataset A = alignment after visual inspection, indels interpreted as missing values;
dataset B = all equivocal indels excluded, unequivocal indels interpreted as missing values; dataset
C = same as B, unequivocal indels given unit weight
DATA SET A
CL n.
L
(bp) MP
trees
DATASET B
Cl
RI
CL
(bp)
DATASET C
n.
L
MP
trees
CI
RI
CL n.
L
(bp) MP
trees
CI
RI
ITS
562 21
157
671 0.66 0.55
503 0.55 0.55
472 3
126
512 0.65
393 0.55
0.57
0.57
472 3
131
547 0.67 0.58
417 0.57 0.58
TrnL
592
30
2
103 0.90 0.87
47 0.78 0.87
570 2
29
95 0.89
47 0.78
0.87
0.87
571 2
34
107 0.90 0.88
51 0.80 0.88
1154
187
1
775 0.69 0.60 1042 2
551 0.57 0.60 156
609 0.69
442 0.57
0.62 1042 2
0.62 165
656 0.70 0.62
470 0.59 0.62
Combined
All the results of the ITS, trnL intron, and
combined cladistic analyses are reported in
Table 2.
In all three datasets, the test for incongruence (Farris et al. 1994), run for 20 replicas,
showed that the ITS and trnL intron matrices
were not significantly incongruent. The combined analyses for the three datasets provided
cladograms entirely congruent with each other,
and the single most parsimonious cladogram
obtained for dataset A (Fig. 1) is one of the
two equally parsimonious cladograms obtained for dataset B and dataset C.
The elision approach generated a 3919
character matrix (of which 1182 informative)
for ITS data, and a 4144 character matrix (of
which 246 informative) for the trnL intron
data. The combined elided dataset (8063 characters, of which 1428 informative) yielded a
single cladogram whose topology is very similar to those obtained from the combined
datasets A, B, C.
The single most parsimonious cladogram
obtained for dataset A (Fig. 1) shows that
Dipsacaceae are divided into two major clades.
The first clade includes Pseudoscabiosa, Succisa
and Succisella, in a sister group relationship
with Knautia, Pterocephalidium, Dipsacus and
Cephalaria; in this latter clade, Knautia
and Pterocephalidium behave as sister groups,
and Dipsacus is sister to Cephalaria. The other
major clade includes Lomelosia in a sister
group relationship with Pycnocomon; this clade
is in turn sister to a clade containing Pterocephalus, sister group to Scabiosa and Sixalix.
Bootstrap support out of 1000 replicas (in
Fig. 1 only the percentages > 50% are shown)
is high for the majority of the clades; the only
notable exceptions are the clade including
Knautia and Pterocephalidium and the one
immediately below (<50%). Branch support
has a distribution which is, not surprisingly,
similar to bootstrap values, and the weakest
areas of the cladogram are the same ones
characterized by low bootstrap percentages
(Fig. 1).
Comparations of sequence substitution
rates (Robinson et al. 1998, Robinson-Rechavi
and Huchon 2000) in the ITS and trnL intron
datasets showed that no one of the tested
lineage evolved significantly faster than any
other.
The trees from the different analyses of the
combined datasets (Table 2) are very similar in
their basic structure. In fact, the extra tree
obtained for datasets B and C has the relative
positions of the Pseudoscabiosa clade (clades
will be indicated by using the name of their
topmost taxon as shown in Fig. 1) and of the
Knautia clade reversed (data not shown); more-
P. Caputo et al.: Molecular phylogeny of Dipsacaceae
over, the elided cladogram from the combined
dataset has a topology which differs from that
shown in Fig. 1 only for the position of Pterocephalidium, which is in this case sister group to
the Pseudoscabiosa clade. From this, we may
infer that the positions of the gaps, or the
different ways in which they are scored, are not
crucial for these datasets. For this reason, we
choose the topology corresponding to dataset A
and shown in Fig. 1 as a working hypothesis.
The trees obtained for the separate ITS and
trnL intron analyses (Table 2), albeit statistically congruent, are different. Notably, the ITS
datasets (excluding the ITS dataset A, for
which the consensus tree is greatly unresolved),
show the Pycnocomon clade as sister group to
Scabiosa, in a more nested position than in the
cladogram of Fig. 1, as well as inversions of
the relative positions of the Pseudoscabiosa
and Knautia clades (data not shown).
The trnL datasets alternately show the
Pycnocomon clade either in the position of
Fig. 1 or as sister group to the other major
clade in the analysis. In all the trnL analyses,
extensive collapses occur among the Pseudoscabiosa, Knautia, and Dipsacus clades as a
consequence of lack of resolution in the data
(data not shown).
The elided ITS and trnL intron datasets
obviously show similar discrepancies. In addition, the two cladograms from the elided trnL
intron dataset show Knautia as the most basal
taxon in the family and Pseudoscabiosa sister
group to the clade including Scabioseae sensu
Mayer and Ehrendorfer (1999).
Discussion
The results shown here address various controversial issues in Dipsacaceae relationships,
in particular for what attains to the circumscription of tribes and to the monophyly of
genera.
Our proposed pattern of descent (Fig. 1)
greatly differs from previous ones based on
classical morphology, and, in particular, is
different from the hypotheses formulated by
Ehrendorfer (1964a,b, 1965), Verláque (1977b,
169
1984a, 1985a) and Caputo and Cozzolino
(1994). The hypothesis presented here, however, is entirely congruent (to the extent of the
taxa present) with recent findings on epicalyx
differentiation (Mayer and Ehrendorfer 1999).
In particular, our results confirm on molecular
grounds the restricted circumscription for
Scabioseae recently proposed by these just
mentioned authors. In fact, the clade including
Lomelosia, Pterocephalus, Pycnocomon, Scabiosa, and Sixalix (i.e. Scabioseae sensu Mayer
and Ehrendorfer) is one of the most supported
(Fig. 1, 92% bootstrap value, 6 BS value).
Similarly, the sister group relationship between
Pycnocomon and Lomelosia, which has been
postulated by Mayer and Ehrendorfer (1999),
but entirely excluded by previous authors, is
well supported (84% bootstrap, 5 BS).
Other well supported clades are those
including Sixalix and Scabiosa (77% bootstrap, 3 BS) and the two just mentioned genera
plus Pterocephalus (82% bootstrap, 3BS).
Outside Scabioseae, the Pseudoscabiosa clade
(95% bootstrap, 10 BS) and the Dipsacus clade
(88% bootstrap, 6 BS) may also be mentioned
in this regard.
The least supported clades (bootstrap values <50%, collapsing in any one-step longer
tree) are the clade including Knautia and
Pterocephalidium and that immediately above.
The position of Knautia is the one of the most
widely varying in the present study. The branch
leading to Knautia is by far the longest in the
cladogram (49 autapomorphies, 26 of which
non homoplasious), in spite of the fact that we
included a species belonging to the most basal
subgenus Trichera Schrad. (Caputo and Cozzolino 1994). Moreover, removal of Knautia
from the combined dataset A causes an increase
of 100% (from 2 to 4) in the branch support in
the clade including Pseudoscabiosa, Succisa,
Succisella, Pterocephalidium, Dipsacus, and
Cephalaria. We suspect that the position of
Knautia in the cladogram of Fig. 1 (and, to a
lower extent, that of Pterocephalidium) may be
influenced by low taxonomic sampling in that
area of the family. Future studies including
representatives of the Eastern sect. Sphaero-
170
dipsacus Lange of genus Dipsacus, of genus
Pterocephalodes, as well as some, putatively
more archaic, Eastern European species of
Knautia (Ehrendorfer 1981) and the aberrant
species Pterocephalus centennii M. J. Cannon,
will possibly contribute to a slightly different
placement of Knautia in the cladogram. Despite
the fact that we regard the place of Knautia in
the cladogram as a possible artifact and,
therefore, we restrain from extensive comments, still, it is worth mentioning that the
position of Knautia and Pterocephalidum, as
well as their sister group relationship, is a novel
interpretation emerging from our analysis.
All four genera for which at least two
species were included appear to be monophyletic (Fig. 1). Given the small number of
representatives per genus, testing monophyly
at genus level was not a goal of this investigation; however, the species selected for this
investigation were chosen in order to maximise
intrageneric diversity and/or differences in
distribution ranges. For this reason the perennial Cephalaria leucantha, belonging to the
archaic, Western Mediterranean subg. Fimbriatocarpus Szabó, was chosen together with the
annual C. syriaca, belonging to the more
widespread subg. Cephalaria. Similarly, the
chamaephyte Sixalix farinosa, a narrow Tunisian endemic appearing as quite archaic in the
genus according to Verláque (1986a), was
selected together with the biennial S. atropurpurea, a widespread, more derived species.
The perennial Japanese endemic Scabiosa
japonica (regarded as a member of sect. Prismakena Bobrov, a group including the most
archaic, Asian members of the genus) was
selected, along with the chamaephytic South
African endemic S. africana and with the
perennial S. uniseta, an Italian representative
of the widespread S. columbaria species group.
Interestingly enough, genus Scabiosa as
circumscribed for the past, even in its narrowest delimitation (i.e. including Lomelosia, Sixalix and Scabiosa s.str.) is not monophyletic, as
Pterocephalus and Pycnocomon would be
nested in it. On the contrary, the nomenclatural
proposal by Mayer and Ehrendorfer (1999), i.e.
P. Caputo et al.: Molecular phylogeny of Dipsacaceae
to keep genus level for Lomelosia, and to use
sectional rank within genus Scabiosa for Sixalix and Scabiosa would correctly represent the
pattern of descent hypothesized here (Fig. 1).
Our phylogenetic hypothesis suggests that
adaptations to seed dispersal have been one of
the strongest driving force in Dipsacaceae
evolution, with similar selective pressures
towards a particular dispersal mode causing
the onset of similar epicalyx shapes, and
correspondingly, of similar dispersal syndromes, in a parallel fashion in various taxa
of the family (Fig. 2A).
Among the taxa used in this analysis, the
great majority is anemochorous. Lomelosia and
Scabiosa have evolved the distal part of the
epicalyx, above the epicalyx tube (the corona)
into a membranous, multinerved, expanded
rim, which helps the diaspore to be carried by
the wind (pterochorous dispersal, i.e. wind
dispersal depending on the presence of a wing).
Furthermore, various species of Lomelosia (as
well as some derived species of Sixalix) have a
calyx which protrudes from the corona and is
covered with short hairs, so exploiting the
opportunity of epizoochorous dispersal.
Pycnocomon and Sixalix are psammophylous (with the exclusion of the widespread
S. atrorpurpurea subsp. maritima) and disperse
by rolling on sand (Verláque 1986b). Both
genera show a very reduced membranous
corona, which is substituted by a more solid
expansion of the distal part of the epicalyx
tube, funnel-shaped in Sixalix and almost
straight in Pycnocomon. However, this diminutive corona is homologous to the expanded
corona of Lomelosia and Scabiosa (Mayer and
Ehrendorfer 1999). The reduction of the
corona in Pycnocomon and Sixalix occurred
homoplasiously, under any character transformation model.
Also Pseudoscabiosa limonifolia has a conspicuous membranous corona; however, as
Mayer and Ehrendorfer (1999) point out, the
distal part of the epicalyx is variable in this
genus, with P. grosii (Font Quer) Devesa
lacking a corona. By plotting presence or
absence of the corona onto the cladogram
P. Caputo et al.: Molecular phylogeny of Dipsacaceae
Valeriana officinalis
Patrinia intermedia
Pseudoscabiosa
Succisella
Succisa
Knautia
Pterocephalidium
Dipsacus
Cephalaria
171
Dispersal syndrome
Pterochorous
Pogonochorous
Autochorous
Myrmecochorous
Unspecialized
Pycnocomon
Ambiguous
Lomelosia
Pterocephalus
Sixalix
A
Scabiosa
Valeriana officinalis
Patrinia intermedia
Pseudoscabiosa
Succisella
Succisa
Knautia
Pterocephalidium
Dipsacus
Cephalaria
Membranous corona
Absent
Present
Ambiguous
Pycnocomon
Lomelosia
Pterocephalus
Sixalix
Scabiosa
Valeriana officinalis
Patrinia intermedia
Pseudoscabiosa
Succisella
Succisa
Knautia
Pterocephalidium
Dipsacus
Cephalaria
B
Plumose multiplied
calyx bristles
Absent
Present
Ambiguous
Pycnocomon
Lomelosia
Pterocephalus
Sixalix
Scabiosa
C
Fig. 2. Morphological characters and ecological adaptations in the studied taxa
plotted onto a simplified version of the cladogram in
Fig. 1 (unambiguous transformations only). A dispersal
syndromes (only those which,
based on external evidence,
are clearly plesiomorphic in
the single terminals are
shown). B membranous corona (a very small number of
species in Dipsacus and Cephalaria have a membranous
corona, and are not shown
here). C plumose multiple
calyx bristles. For simplicity’s
sake, characters which are
inapplicable in the outgroup
(e.g. the characters related to
the epicalyx) have been reconstructed as absent
172
(Fig. 2B), under all character transformation
models, the wide, membranous corona is
homoplasious in P. limonifolia, as compared
to Lomelosia, Pycnocomon, Scabiosa, and
Sixalix.
Other Dipsacaceae have developed a membranous corona, whether expanded and evidently nervate or minute and without apparent
nerves (Mayer and Ehrendorfer 1999, 2000):
among them, a genus absent in our analysis,
Pterocephalodes p.p. (most conspicuous in
P. bretschneideri (Batal.) V. Mayer et Ehrend.)
and Pterocephalus p.p. (e.g. P. pyrethrifolius
Boiss. et Hohen.). In the latter genus, the
epicalyces show a great diversity in structural
detail, in spite of their general similarity
(Mayer and Ehrendorfer 2000). Such variability, especially in the presence and shape of the
corona, may be related to the fact that the
corona does not seem to have an evident
adaptative value towards dispersal and, as a
consequence, its presence and shape may not
be strictly constrained by selection. The species
selected for the present investigation, the
Balkanic P. perennis, shows a minute membrane joining the teeth present at the top of the
epicalyx tube. However, the presence of a
corona is regarded as an apomorphic feature in
Pterocephalus, and the most archaic species of
the genus lack it (Mayer and Ehrendorfer
2000, Fig. 25).
Other genera, i.e. Pterocephalidium and
Pterocephalus (as well as Pterocephalodes and
Pycnocomon intermedium, both absent from
this analysis) have multiple calyx bristles with
a feathery indumentum, aiming at pogonochorous dispersal (i.e. wind dispersal depending on the presence of a pappus). Within the
limits of the taxa present in this study, also this
character developed homoplasiously (see also
Mayer and Ehrendorfer 1999, 2000), irrespectively of the character transformation model
chosen (Fig. 2C).
The other major clade observed in the
cladogram of Fig. 1, i.e. that including Cephalaria, Dipsacus, Knautia, Pseudoscabiosa,
Pterocephalidium, Succisa, and Succisella does
not show such a high elaboration in the
P. Caputo et al.: Molecular phylogeny of Dipsacaceae
epicalyx morphology. Conversely, the clade
shows a greater variety of diaspore dispersal
syndromes, not always linked to morphological differentiations in the epicalyx or in the
calyx. Notable exceptions in this respect are
Pseudoscabiosa, Pterocephalidium and Knautia. In Pseudoscabiosa, as already said, a
membranous corona is either present [in
P. limonifolia and P. saxatilis (Cav.) Devesa],
or absent (in P. grosii). Interestingly, the lack
of corona in the latter species corresponds to
an increase in length, number and hairiness of
the calyx bristles, as compared to the other
two species, indicating a possible incipient
transition from pterochory to pogonochory
(or vice-versa).
Pterocephalidium, the only genus in the
family having two stamens instead of four, is
clearly pogonochorous, with a plumose, pappus-like calyx. However, in this case the distal
region of the epicalyx tube is elaborated into a
single, very long, flexible awn of uncertain
function (López Gonzáles 1987).
In Knautia the pedicel of the dorsiventrally
flattened epicalyx has developed into an elaiosome, and its dispersion is myrmecochorous
(Fig. 2A).
In the other genera, the epicalyx seems to
be less directly involved in dispersion (Verláque 1985a, 1986b). In fact, the majority of the
species of Dipsacus and Cephalaria rely on a
combination of rigid, often acuminate, involucral/receptacular bracts in the capitulum,
and of elastic stems, hereby allowing
short-distance projection of diaspores. In some
cases these diaspores subsequently adhere to
animal furs, indicating either an autochorous
or an epizoochorous dispersal syndrome
(Fig. 2A), or a combination of both (Verláque
1985a, 1986b). For Succisa and Succisella, no
correspondence between any morphological
feature and a dispersal syndrome is observed;
both genera are for most part confined to
humid environments and have perhaps simplified their epicalyx by loosing features which
were less valuable in the that environment.
These taxa have been interpreted by various
authors (e.g. Verláque 1986b, Caputo and
P. Caputo et al.: Molecular phylogeny of Dipsacaceae
Cozzolino 1994) as basal within Scabioseae
sensu lato; however, they are clearly external to
that tribe both according to Mayer and
Ehrendorfer (1999) and to the data presented
here, which show the two genera in a sister
relation (with very high bootstrap value and
decay index) with Pseudoscabiosa.
Despite the differences in dispersal strategies, which have apparently contributed to
cause adaptative radiation in various taxa and,
as a consequence, may have influenced the
evolution rate, comparisons of sequence substitution rates (Robinson et al. 1998, Robinson-Rechavi and Huchon 2000) showed that
no one of the tested lineages evolved significantly faster than any other; in particular, not
even a comparison among pterochorous,
pogonochorous, autochorous, and myrmecochorous groups did show significant differences. However, our choice of taxa is
unbalanced under this respect (e.g. only a
single species of Knautia, i.e. a single myrmecochorous terminal), and also annuals (which
constitute derived species in various genera
and which often have a higher evolution rate)
are underrepresented in our data set. This
unbalance may have influenced the results of
the test.
For all what said above, also our study,
after the work by Mayer and Ehrendorfer
(1999) would indicate that the gross morphology of the epicalyx is deceptive in inferring
relationships, as the whole family is beset by
rampant homoplasies originated by selective
constraints towards several diaspore dispersal
syndromes.
The presence of a diaphragma, i.e. a
protrusion of the distal part of the inner side
of the epicalyx tube, which, by enclosing the
calyx stalk, secures a better encasing of the
achene in the epicalyx, is much more promising in assessing relationships (Mayer and
Ehrendorfer 1999, 2000). This structure, together with the corresponding diversification
of an epidiaphragma (Mayer and Ehrendorfer
1999), is present in virtually all members of
Lomelosia, Scabiosa, Sixalix, and in various
species of Pterocephalus (including P. perennis,
173
which was used for this study), but absent
from all other Dipsacaceae. However, the
diaphragma, together with the membranous
corona, may be regarded as synapomorphic
for Scabioseae sensu Mayer and Ehrendorfer
(1999). This character may be either reverted
more than once (loss in the immediate ancestors of Pterocephalus and novel development
within the genus) or occurrence in Pterocephalus is plesiomorphic. The latter hypothesis,
however, is excluded by Mayer and Ehrendorfer (2000).
Palynological and karyological evidences
(Verláque 1985a, 1986b; Caputo and Cozzolino 1994; Mayer and Ehrendorfer 1999) are
much more supportive of our phylogenetic
hypothesis. Dipsacaceae pollen (Verláque
1985a, 1986b) is either triporate (in Knautia,
Lomelosia, Pterocephalidium, Pycnocomon,
and in the aberrant annual Scabiosa parviflora
Desf.) or tricolpate (in Cephalaria, Dipsacus,
Pseudoscabiosa, Pterocephalus, Scabiosa, Sixalix, Succisa, and Succisella). Tricolpate pollen,
also present in all Valerianaceae, is unequivocally reconstructed as plesiomorphic in Dipsacaceae (data not shown); triporate pollen has
independently evolved more than once, in
Knautia/Pterocephalidium, in Lomelosia/Pycnocomon, and in S. parviflora.
Chromosome numbers in the family are
less amenable to an unequivocal reconstruction. In fact, in the majority of the large
genera, chromosome numbers show dysploid
variation. However, the haploid numbers
appearing as plesiomorphic in the genera in
which they occur are n ¼ 8 in Pterocephalidium, Scabiosa, Sixalix (Verláque 1985b,
1986a,b), n ¼ 9 in Cephalaria, Dipsacus, Pycnocomon, Pterocephalus and Lomelosia (Verláque 1977a, 1985a), n ¼ 10 in Knautia,
Pseudoscabiosa, Succisa and Succisella (Ehrendorfer 1962, 1981; Verláque 1985b, 1986a). By
plotting chromosome haploid numbers on the
cladogram (data not shown), it appears that
n ¼ 8 independently originated twice in the
family (in Pterocephalidium, as well as in
Scabiosa and Sixalix); n ¼ 9 is ambiguous in
reconstruction; regardless, it is reconstructed
174
as plesiomorphic in the family under both an
accelerated and a delayed character transformation model (data not shown). However, the
character state n=9 is synapomorphic for the
two groups in which it appears only under a
delayed transformation model. The state
n ¼ 10 is also ambiguous: it appears as
uniquely derived in both the Pseudoscabiosa
clade and Knautia only under an accelerated
transformation model.
In spite of all the homoplasies described
above, it may be noted that our present
phylogenetic hypothesis requires a smaller
number of homoplasious changes in the presence of diaphragma, pollen morphology and
chromosome numbers as compared to previous ones (e.g. Verláque 1986b, Caputo and
Cozzolino 1994). Furthermore our evolutionary reconstruction is almost entirely congruent
with the novel insights on epicalyx morphology shown by Mayer and Ehrendorfer (1999).
The few possible problems of our proposed
pattern of descent (e.g. the position of Knautia)
will be probably solved by both the inclusion
of some critical taxa (members of Pterocephalodes; basal species of Dipsacus, representatives
of the derived subgenera of Knautia) and the
extension of the molecular dataset.
References
Aceto S., Caputo P., Cozzolino S., Gaudio L.,
Moretti A. (1999) Phylogeny and evolution of
Orchis and allied genera based on ITS DNA
variation: morphological gaps and molecular
continuity. Mol. Phylogenet. Evol. 13: 67–76.
Backlund A., Bremer B. (1997) Phylogeny of the
Asteridae s. str. based on rbcL sequences, with
particular reference to the Dipsacales. Plant
Syst. Evol. 207: 225–254.
Baldwin B. G., Sanderson M. J., Porter M. J.,
Wojciechowski M. F., Campbell C. S., Donoghue M. J. (1995) The ITS region of nuclear
ribosomal DNA: a valuable source of evidence
in angiosperm phylogeny. Ann. Missouri Bot.
Gard. 82: 247–277.
Caputo P., Cozzolino S. (1994) A cladistic analysis
of Dipsacaceae (Dipsacales). Plant Syst. Evol.
189: 41–61.
P. Caputo et al.: Molecular phylogeny of Dipsacaceae
Caputo P., Cozzolino S. (1995) Cladogeny in
Dipsacaceae: dispersal and vicariance models.
Boll. Soc. Sarda Sci. Nat. 30: 233–243.
Caputo P., Stevenson D.W., Wurtzel E.T. (1991) A
phylogenetic analysis of American cycads (Cycadales) using chloroplast DNA restriction fragment polymorphisms. Brittonia 43: 135–145.
Devesa J. A. (1984a) Revision of the genus Scabiosa in Spain and Balearic Islands. Lagascalia 12:
143–212.
Devesa J. A. (1984b) Pseudoscabiosa, genero nuevo
de Dipsacaceae. Lagascalia 12: 213–221
Doyle J. J., Doyle J. L. (1990) Isolation of plant
DNA from fresh tissue. Focus 12: 13–15.
Ehrendorfer F. (1964a) Cytologie, Taxonomie und
Evolution bei Samenpflanzen. In: Turril W. B.
(ed.) Vistas in Botany. 4. The MacMillan Company, New York, pp. 99–186.
Ehrendorfer F. (1964b) Über stammesgeschichtliche Differenzierungsmuster bei den Dipsacaceen.
Ber. Deutsch. Bot. Ges. 77: 83–94.
Ehrendorfer F. (1965) Evolution and karyotype
differentiation in a family of flowering plants:
Dipsacaceae. Genetics Today (Proc. XI International Congress of Genetics, The Hague, The
Netherlands, 1963) 2: 399–407.
Ehrendorfer F. (1981) Neue Beiträge zur Karyosystematik und Evolution der Gattung Knautia
(Dipsacaceae) in den Balkanländern. Bot. Jahrb.
Syst. 102: 225–238.
Farris J. S., Källersjö M., Kluge A. G., Bult C.
(1994) Testing significance of incongruence.
Cladistics 10: 315–319.
Gielly L., Taberlet P. (1996) A phylogeny of European gentians inferred from chloroplast trnL (UAA)
intron sequences. Bot. J. Linn. Soc. 120: 57–75.
Goloboff P. (1999) Nona. Instruction manual.
Published by the author, S. M. de Tucumán,
Argentina.
Greuter W., Burdet R. (1985) Dipsacaceae. In:
Greuter W., Raus T. (eds.) Med-Checklist
Notulae 11. Willdenowia 15: 71–76.
Greuter W., Burdet H. M., Long G. (eds.) (1986)
Med-Checklist. Vol. 2. Editions des Conservatoire et Jardin botaniques de la Ville de Genève,
Genève, pp. 176–198.
López Gonzáles G. (1987) Pterocephalidium, un
nuevo género ibérico de la familia Dipsacaceae.
Anales Jard. Bot. Madrid 43: 245–252.
Mayer V., Ehrendorfer F. (1999) Fruit differentiation, palynology, and systematics in the Scabi-
P. Caputo et al.: Molecular phylogeny of Dipsacaceae
osa group of genera and Pseudoscabiosa (Dipsacaceae). Plant Syst. Evol. 216: 135–166.
Mayer V., Ehrendorfer F. (2000) Fruit differentiation, palynology, and systematics in Pterocephalus Adanson and Pterocephalodes, gen. nov
(Dipsacaceae). Bot. J. Linn. Soc. 132: 47–78.
Nixon K. C. (1999) Winclada (beta) ver. 0.9.9.
Published by the author, Ithaca, NY.
Robinson M., Gouy M., Gautier C., Mouchiroud D.
(1998) Sensitivity of the relative-rate test to
taxonomic sampling. Mol. Biol. Evol. 15:1091–
1098.
Robinson-Rechavi M., Huchon D. (2000) RRTree:
Relative-Rate Tests between groups of sequences
on a phylogenetic tree. Bioinformatics 16: 296–
297.
Sanger F., Niklen S., Coulson A. R. (1977) DNA
sequencing with chain terminating inhibitors.
Proc. Natl. Acad. Sci. USA 74: 5463–5467.
Taberlet P., Gielly L., Pautou G., Bouvet J. (1991)
Universal primers for amplification of three noncoding regions of chloroplast DNA. Plant Mol.
Biol. 17: 1105–1109.
Thompson J. D., Higgins D. G., Gibson T. J.
(1994) CLUSTAL W: improving the sensitivity
of progressive multiple sequence alignment
through sequence weighting, positions-specific
gap penalties and weight matrix choice. Nucl.
Acids Res. 22: 4673–4680.
Verláque R. (1977a) Rapports entre les Valerianaceae, les Morinaceae et les Dipsacaceae. Bull.
Soc. bot. Fr. 124: 475–482.
Verláque R. (1977b) Importance du fruit dans la
determination des Dipsacaceae. Bull. Soc. bot.
Fr. 124: 515–527.
175
Verláque R. (1984a) A biosystematic and phylogenetic study of the Dipsacaceae. In: Grant R. (ed.)
Plant biosystematics. Academic Press, Toronto,
pp. 307–320.
Verláque R. (1984b) Etude biosystématique et
phylogénétique des Dipsacaceae. I. – Délimitation des Dipsacaceae à l’intérieur des Dipsacales,
rapports avec les autres familles de l’ordre. Rev.
Gen. Bot. 91: 81–121.
Verláque R. (1985a) Etude biosystématique et
phylogénétique des Dipsacaceae. II - Caractères
gènèraux des Dipsacaceae. Rev. Cytol. Biol.
Veg. Le Botaniste 8: 117–168.
Verláque R. (1985b) Etude biosystématique et
phylogénétique des Dipsacaceae. III – Tribus
des Knautieae et des Dipsaceae. Rev. Cytol.
Biol. Veg. Le Botaniste 8: 171–243.
Verláque R. (1986a) Etude biosystématique et
phylogénétique des Dipsacaceae. IV – Tribus
des Scabioseae (phylum n° 1, 2, 3). Rev. Cytol.
Biol. Veg. Le Botaniste 9: 5–72.
Verláque R. (1986b) Etude biosystématique et
phylogénétique des Dipsacaceae. V - Tribus des
Scabioseae (phylum n° 4) et conclusion. Rev.
Cytol. Biol. Veg. Le Botaniste. 9: 97–176.
Wheeler W. C., Gatesy J., DeSalle R. (1995)
Elision: a method for accommodating multiple
molecular sequence alignments with alignmentambiguous sites. Mol. Phylog. Evol. 4: 1–9.
Addresses of the authors: Paolo Caputo (corresponding author; e-mail: pacaputo@unina.it),
Salvatore Cozzolino, Aldo Moretti, Dipartimento
di Biologia vegetale, Università di Napoli Federico
II, Via Foria 223, I-80139 Napoli, Italy.