bs_bs_banner
Botanical Journal of the Linnean Society, 2013, 172, 106–126. With 3 figures
Towards a new classification of the giant paraphyletic
genus Cyperus (Cyperaceae): phylogenetic relationships
and generic delimitation in C4 Cyperus
ISABEL LARRIDON1*, KENNETH BAUTERS1, MARC REYNDERS1, WIM HUYGH1,
A. MUTHAMA MUASYA2, DAVID A. SIMPSON3 and PAUL GOETGHEBEUR1
1
Research Group Spermatophytes, Department of Biology, Ghent University, K. L. Ledeganckstraat
35, 9000 Gent, Belgium
2
Botany Department, University of Cape Town, Rondebosch 7700, South Africa
3
Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AB, UK
Received 2 April 2012; revised 14 December 2012; accepted for publication 14 December 2012
Maximum likelihood and Bayesian inference analyses of nuclear ribosomal DNA (ETS1f) and plastid DNA
(rpl32-trnL, trnH-psbA) sequence data are presented for ‘C4 Cyperus’ (Cyperaceae). The term ‘C4 Cyperus’
encompasses all species of Cyperus s.l. that use C4 photosynthesis linked with chlorocyperoid vegetative anatomy.
Sampling comprises 107 specimens of 104 different taxa, including many of the subdivisions of C4 Cyperus s.s. and
all C4 segregate genera (Alinula, Ascolepis, Kyllinga, Lipocarpha, Pycreus, Queenslandiella, Remirea, Sphaerocyperus and Volkiella). According to our results, C4 Cyperus is a well-supported monophyletic clade nested in C3
Cyperus. Despite the lack of resolution along the backbone of the C4 Cyperus clade and for some internal branches,
several well-supported clades can be distinguished. The first clade in C4 Cyperus is formed by Cyperus cuspidatus
and C. waterloti. Other recognizable and well-supported clades correspond to segregate genera, i.e. Ascolepis,
Lipocarpha including Volkiella, and Kyllinga. Species of C4 Cyperus s.s. form a core grade in which the C4 segregate
genera are embedded. Pycreus, the largest segregate genus composed of c. 120 species, is not monophyletic as it
includes several C4 species of Cyperus s.s. This study establishes a phylogenetic framework for revising the
classification and character evolution in Cyperus s.l. © 2013 The Linnean Society of London, Botanical Journal
of the Linnean Society, 2013, 172, 106–126.
ADDITIONAL KEYWORDS: Cypereae – Cyperoideae – molecular phylogeny – paraphyly – species radiation
– systematics.
INTRODUCTION
Cyperaceae (the sedge family) has an almost cosmopolitan distribution and plays a dominant role in
wetland vegetation. The many reductions and convergences in the inflorescences of Cyperaceae have
impeded evolutionary reconstruction (homology questions, e.g. Bruhl, 1991; Vrijdaghs et al., 2009, 2010;
Muasya et al., 2009b) and classification (e.g. Clarke,
1908; Kükenthal, 1935–36; Kern, 1974; Haines & Lye,
1983; Bruhl, 1995; Goetghebeur, 1998). Based on
recent molecular phylogenetic studies, Cyperaceae
*Corresponding author. E-mail: isabel.larridon@ugent.be
106
consists of two main clades, corresponding to subfamilies Cyperoideae and Mapanioideae (Simpson
et al., 2003, 2007; Muasya et al., 2009a). In Cyperoideae, two clades stand out because of their extraordinary species diversity: (1) the clade corresponding
to the predominantly temperate tribe Cariceae (c.
1950 spp.); and (2) the clade corresponding to the
mainly tropical tribe Cypereae (c. 1120 spp.).
Together, they cover nearly three-fifths of the species
diversity in Cyperaceae (Govaerts et al., 2012).
Recent molecular phylogenetic studies of Cyperaceae (Simpson et al., 2003, 2007; Muasya et al.,
2009a) have shown Cypereae sensu Goetghebeur
(1998) to be monophyletic, but the generic delimita-
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126
C4 CYPERUS PHYLOGENY (CYPERACEAE)
107
Table 1. The genera in Cypereae currently accepted by Govaerts et al. (2012), plus the recently published genus
Dracoscirpoides (Muasya et al., 2012) and the recent phylogenetic novelty Erioscirpus (Yano et al., 2012). The segregate
genera using the C4 photosynthetic pathway are underlined. The taxa indicated by an asterisk were recently included in
Cyperus (Larridon et al., 2011b)
Cypereae
Ficinia clade
?
Cyperus clade
Dracoscirpoides Muasya (3 spp.)
Erioscirpus Palla (2 spp.)
Hellmuthia Steud. (1 sp.)
Ficinia Schrad. (75 spp.)
Isolepis R.Br. (76 spp.)
Scirpoides Ség. (4 spp.)
Androtrichum (Brongn.) Brongn.
Alinula J.Raynal (4 spp.)
Ascolepis Nees ex Steud., (22 spp.)
Courtoisina Soják (2 spp.)*
Kyllinga Rottb. (74 spp.)
Kyllingiella R.W.Haines & Lye (4 spp.)*
Lipocarpha R.Br. (36 spp.)
Oxycaryum Nees (1 sp.)*
Pycreus P.Beauv. (114 spp.)
Queenslandiella Domin (1 sp.)
Remirea Aubl. (1 sp.)
Sphaerocyperus Lye (1 sp.)
Volkiella Merxm. & Czech (1 sp.)
tions in Cypereae remain controversial (Muasya
et al., 2009b). In the past, members of Cypereae were
circumscribed as having spikelets with distichous
glumes and reduced, perianthless flowers (e.g.
Kükenthal, 1935–36). However, neither the distichy
of the glumes nor the absence of a perianth can be
regarded as phylogenetically informative characters
(e.g. Vrijdaghs et al., 2006; Muasya et al., 2009a, b, in
press). Currently, members of Cypereae are circumscribed by the presence of a Cyperus-type embryo or
the similar Ficinia-type embryo (Van der Veken, 1965;
Goetghebeur, 1998; Muasya et al., 2009a, b). The
presence of various combinations of characters (e.g.
reduced flowers, reduced and/or contracted inflorescences) and convergent morphologies has led to the
misinterpretation of the relationships of many lineages of Cypereae. A number of taxa (belonging
especially to Erioscirpus Palla, Ficinia Schrad, Hellmuthia Steud., Isolepis R.Br., Kyllingiella R.W.Haines
& Lye, Oxycaryum Nees, Scirpoides Séq.) have been
allocated to various tribes in Cyperaceae, including
Scirpeae, Rhynchosporeae, Hypolytreae and Schoeneae (e.g. Kunth, 1837; Nees von Esenbeck, 1842;
Steudel, 1854–55; Clarke, 1908). However, extensive
anatomical (Kranz anatomy), embryographical and
molecular phylogenetic studies (e.g. Van der Veken,
1965; Goetghebeur, 1986, 1998; Bruhl, 1995; Muasya
et al., 2001a, 2009a, b; Muasya, Simpson & Chase,
2002; Simpson et al., 2003, 2007; Larridon et al.,
2011a, b; Yano et al., 2012) have revealed that these
genera are closely related to Cyperus L. Consequently,
the reinterpretation of the morphological characters
of these genera in the context of Cypereae is required.
On the basis of molecular phylogenetic studies
(e.g. Simpson et al., 2007; Muasya et al., 2009a),
two clades are recognized in Cypereae: (1) the
Ficinia clade; and (2) the Cyperus clade. The first,
smaller clade (c. 160 spp.) consists of several genera
with a mainly southern African distribution, a ficinoid habit (hemicryptophytes, culm scapose, inflorescence capitate and appearing pseudolateral
with main involucral bract being stem-like) and
mostly spiral glumes. The basalmost branches
include species with perianth parts (Dracoscirpoides
Muasya, Erioscirpus, Hellmuthia; Vrijdaghs et al.,
2006; Muasya et al., 2012; Yano et al., 2012). Prior
to the embryographical study of Van der Veken
(1965), most of these genera had been classified in
or near Scirpus L.
The second, larger, pantropical clade (c. 950 spp.),
with mostly distichous glumes, comprises a paraphyletic Cyperus s.s. as the core genus (c. 700 spp.), in
which at least 12 segregate genera are nested
(Goetghebeur, 1998; Govaerts et al., 2012; see
Table 1). The branch leading to Androtrichum
(Brongn.) Brongn. (two species) appears to be at the
base of the Cyperus clade (Muasya et al., 2002, in
press), but this needs further confirmation. Although
molecular phylogenetic studies have revealed that all
of these genera are nested in Cyperus (e.g. Muasya
et al., 2002; Larridon et al., 2011a), there has been
considerable discussion about whether to include
these taxa in Cyperus. Contemporary treatments
either recognize the segregate genera as separate
from Cyperus (e.g. Bruhl, 1995; Goetghebeur, 1998;
Govaerts et al., 2007, 2012) or merge them into
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126
108
I. LARRIDON ET AL.
Cyperus at an infrageneric rank (e.g. Kükenthal,
1935–36; Haines & Lye, 1983; Lye, 1997).
The Cyperus clade includes a grade of branches
characterized by C3 photosynthesis (C3 Cyperus, c.
190 spp.), which were well resolved in a combined
analysis of ETS1f, trnH-psbA and rpl32-trnL
(Larridon et al., 2011a). In C3 Cyperus, most sections
of the classification according to Kükenthal (1935–36)
were confirmed. Larridon et al. (2011b) included the
C3 segregates Courtoisina Soják, Oxycaryum and
Kyllingiella in Cyperus, supported by molecular data,
combined with morphology, embryography, ontogeny
and anatomy.
Nested in C3 Cyperus is a highly diverse clade (C4
Cyperus, c. 760 spp.) with the C4 photosynthetic
pathway as a synapomorphy (e.g. Muasya, Simpson &
Chase, 2001b; Muasya et al., 2002, 2009a, in press;
Besnard et al., 2009; Larridon et al., 2011a). The nine
C4 segregate genera represent c. 30% of diversity in
the C4 Cyperus clade. Figure 1 shows some of the
morphological diversity of C4 Cyperus lineages. They
are generally considered to be well-delimited entities
(e.g. Goetghebeur, 1998) and are circumscribed by a
combination of morphological characters, including
inflorescence and spikelet morphology, unit of dispersal and nutlet orientation (e.g. Muasya et al., 2009b;
Vrijdaghs et al., 2011; Reynders et al., 2012; Figure 2).
However, the mutual relationships of the taxa in C4
Cyperus still need to be determined.
PARAPHYLY
AND MODERN CLASSIFICATION
STRATEGIES
With the advancement of molecular phylogenetic
research, species relationships and evolutionary patterns in giant genera provide new and valuable opportunities to study evolutionary processes. Often, these
giant genera appear to contain derived lineages that
have, up to now, been considered as separate genera
(e.g. Acacia Mill., Miller & Bayer, 2001; Carex L.,
Starr & Ford, 2009; Croton L., Berry et al., 2005;
Euphorbia L., Steinmann & Porter, 2002; Salvia L.,
Walker et al., 2004). The development of new classifications, encompassing the concept of monophyly for
these large paraphyletic entities and their segregate
genera, has been highly challenging. Three main
strategies can be implemented: (1) splitting; (2)
accepting paraphyletic taxa; and (3) lumping. Splitting paraphyletic taxa into a large number of small
genera has been proposed for a number of large
genera (e.g. Acacia; Maslin, Miller & Seigler, 2003).
The decision on where to split needs to be based on a
well-resolved phylogenetic hypothesis, and there are
challenges to identifying diagnostic characters for the
segregate entities and controversies about name
application (Acacia; e.g. Moore et al., 2010, 2011;
Smith & Figueiredo, 2011; Thiele et al., 2011). A
second, less popular, strategy is a classification in
which various segregate genera are upheld which are
themselves monophyletic, but remain part of a paraphyletically circumscribed giant genus. The use of
paraphyletic genera has been defended by some
authors (e.g. Brummitt, 1996; Brummitt & Sosef,
1998), but has been strongly opposed by others (e.g.
Nelson, Murphy & Ladiges, 2003). The third and most
popular strategy when dealing with paraphyletic
giant genera is the lumping of all the segregates into
a broader circumscribed genus (e.g. in Euphorbia;
Steinmann & Porter, 2002). A negative consequence of
lumping is that it can become difficult to describe
clearly the giant genus as a whole.
OBJECTIVES
In the present study, molecular phylogenetic data of
the Cyperus clade were analysed: (1) to determine the
mutual relationships of the taxa (i.e. genera, sections,
species) included in C4 Cyperus; (2) to test whether
the segregate genera and infrageneric taxa in C4
Cyperus (Kükenthal, 1935–36; Govaerts et al., 2012)
are monophyletic; and (3) to examine the most
suitable classification strategy for C4 Cyperus.
Papers documenting the necessary nomenclatural/
taxonomical changes based on the results presented
in this article and more detailed studies of several of
the larger C4 segregates will be published elsewhere.
This study is part of a larger research project aimed
at recircumscribing Cyperus as a monophyletic unit
and at creating a new infrageneric classification of
the genus supported by both molecular and morphological data.
MATERIAL AND METHODS
One hundred and seven samples from 104 different
taxa were used for this study. Sixty-seven sequences
from 23 species were used from a previous study
(Larridon et al., 2011a). The other 213 sequences from
81 different taxa were newly generated for this study.
The samples with species names, voucher information, origin and GenBank accession numbers for the
sequences are given in Table 2. Taxa within Cyperus
were selected to represent a broad morphological and
geographical range and to include a wide range of the
traditionally recognized sections, subgenera and segregate genera. As this study assesses relationships
above the rank of species, multiple species samples
and infraspecific taxa were generally not used. The
outgroup taxa were selected on the basis of the
results of previous molecular phylogenetic analyses of
Cypereae by Muasya et al. (2002, 2009a) and
Larridon et al. (2011a). Taxonomic information for
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126
C4 CYPERUS PHYLOGENY (CYPERACEAE)
Figure 1. See caption on next page.
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126
109
110
I. LARRIDON ET AL.
Figure 1. Morphological diversity in C4 Cyperus. A, Cyperus cyperoides (L.) Kuntze with strongly contracted spikes of
spikelets in an anthelate inflorescence. B, Pycreus polystachyos (Rottb.) P.Beauv. with spikes of spikelets in an anthelate
inflorescence. C, Cyperus laevigatus L. with a reduced inflorescence consisting of only a few sessile spikelets in a
pseudolateral inflorescence. D, Lipocarpha chinensis (Osbeck) J.Kern with three sessile pseudospikelets. E, Cyperus
capitatus with a capitate inflorescence. F, Kyllinga polyphylla Willd. ex Kunth with a capitate inflorescence of reduced,
deciduous spikelets. G, Cyperus ustulatus A.Rich. with contracted spikes of spikelets in an anthelate inflorescence. H,
Cyperus waterloti Cherm. with an inflorescence of digitately clustered spikelets. Photographs A–G taken by M. Reynders
in the Ghent University Botanical Garden, H taken by W. Huygh at Cirque Rouge near Mahajanga, Madagascar.
Figure 2. Three-dimensional reconstruction of the spikelet evolution in the Cyperus clade. The illustrations were drawn
in Rhinoceros 3D® (Mc Neel, Seattle, WA, USA) by M. Reynders. The basic Cyperus spikelet with distichous glumes
developed several times independently into lineages with spiral glumes. In addition, deciduous spikelets originated
several times and, from there, different reduction lineages can be identified resulting in single-flowered spikelets. In the
extreme situation, the bracts subtending the spikelets behave like glumes bearing the strongly reduced spikelets. Difficult
interpretation of the latter resulted in the classification of these taxa among various Cyperaceae tribes before their affinity
with Cyperus had been resolved.
most taxa mentioned (such as author, place and date
of publication, synonyms, distribution) follows
Govaerts et al. (2007, 2012). The molecular phylogenetic hypothesis obtained was compared with the
classification of Kükenthal (1935–36). Detailed information on the nomenclature of generic and subdivisional names of the Cyperus clade (including the
synonymy of the names used by Kükenthal) is given
in Huygh et al. (2010), Larridon et al. (2011c) and
Reynders et al. (2011).
Samples were either of wild origin, mostly collected during recent field expeditions (silica dried),
or sampled from plants cultivated at the Ghent University Botanical Garden. Additional dried leaf
samples were selected from herbarium specimens
(GENT, BR). The DNA extraction protocol, markers
(ETS1f, rpl32-trnL and trnH-psbA) and material and
methods for polymerase chain reaction (PCR) amplification and sequencing and obtaining alignments
used in this study follow Larridon et al. (2011a).
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126
C4 CYPERUS PHYLOGENY (CYPERACEAE)
111
Table 2. List of the samples used in the molecular study with species names, voucher information (*leaf sample courtesy
of the collector A.M. Muasya), origin and GenBank accession numbers for the sequences
Taxon
Voucher (herbarium)
Origin
ETS1f
trnH-psbA
rpl32-trnL
Alinula paradoxa (Cherm.)
Goetgh. & Vorster
Ascolepis brasiliensis
(Kunth) Benth. ex
C.B.Clarke
Ascolepis eriocauloides
(Steud.) Nees ex Steud.
Ascolepis hemisphaerica
Peter ex Goethg.
Ascolepis protea Welw.
Reid 1027 (GENT)
South Africa
HQ705964
–
HQ705894
Larridon et al. 2010-0304
(GENT)
Madagascar
HE993954
HE993894
HE993685
De Wilde s.n. (BR)
Congo
HE993955
HE993895
–
Reekmans 6729 (GENT)
Burundi
HE993956
–
–
Malaisse & Kisimba 695
(GENT)
Malaisse & Goetghebeur
846 (GENT)
Hess 52/1581 (GENT)
Congo
HE993957
HE993896
HE993686
Congo
HE993958
HE993897
–
Angola
HE993959
HE993898
HE993687
Goetghebeur 11516 (GENT)
Muasya & Ramdhani 2722
(BOL)
Laegaard et al. 17024
(GENT)
Goetghebeur 10744 (GENT)
Reynders & Sabulao 15
(GENT)
Goetghebeur 11988 (GENT)
Rostad s.n. GENT
Jongkind & Nieuwhuis
2847 (GENT)
Muasya et al. 2529 (EA)
Muasya & Muthama 1251
(EA)
Goetghebeur 5601 (GENT)
Muasya & Knox 954 (EA)
Goetghebeur 11303 (GENT)
Carter 4355 (GENT)
Goetghebeur 4329 (GENT)
Muasya & Muthama 1269
(EA)
Dhondt 9 (GENT)
BG Ghent
South Africa
HQ705948
HE993960
HQ705818
HE993899
HQ705878
HE993688
Senegal
HE993961
HE993900
HE993689
BG Ghent
Philippines
HE993962
HE993963
HE993901
HE993902
HE993690
HE993691
BG Ghent
USA
Ghana
HE993964
HE993965
HQ705954
HE993903
HE993904
HQ705823
HE993692
–
HQ705884
Kenya
Kenya
HE993966
HE993967
HE993905
–
HE993693
HE993694
Cuba
Tanzania
BG Nantes, BG Ghent
Florida
South Africa
Kenya
HQ705959
HE993968
HQ705960
HE993969
HE993970
HQ705927
HQ705827
–
HQ705828
HE993906
HE993907
HQ705803
HQ705889
–
HQ705890
HE993695
HE993696
HQ705803
Madagascar
HE993971
–
HE993697
Burkina Faso
Philippines
HE993972
HE993973
HE993908
–
HE993698
HE993699
Kenya
HQ705961
HQ705829
HQ705891
Morocco, BG Ghent
Kenya
HE993975
HE993974
HE993910
HE993909
–
HE993700
Morocco, BG Ghent
Netherlands
Ecuador
HE993976
HE993977
HQ705910
HE993911
HE993912
–
HE993701
HE993702
HQ705846
Kenya
HQ705949
HQ705819
HQ705879
Somalia
HE993978
HE993913
HE993703
Hawaii
HE993979
HE993914
HE993704
Ascolepis pusilla Ridl.
Cyperus alopecuroides
Rottb.
Cyperus alternifolius L.
Cyperus aterrimus Hochst.
ex Steud.
Cyperus bulbosus Vahl
Cyperus capitatus Vand.
Cyperus compressus L.
Cyperus congestus Vahl
Cyperus croceus Vahl
Cyperus cuspidatus Kunth
Cyperus dives Delile
Cyperus dubius Rottb.
Cyperus
Cyperus
Cyperus
Cyperus
Cyperus
Cyperus
elegans L.
endlichii Kük.
esculentus L.
filiculmis Vahl
fulgens C.B.Clarke
haspan L.
Cyperus
fallax
Cyperus
Cyperus
impubes Steud. var.
(Cherm.) Kük.
iria L.
javanicus Houtt.
Cyperus kerstenii Boeck.
Cyperus laevigatus L. 053
Cyperus laevigatus L. 138
Cyperus laevigatus L. 142
Cyperus longus L.
Cyperus luzulae (L.) Retz.
Cyperus marginatus Thunb.
Cyperus meeboldii Kük.
Cyperus meyenianus Kunth
Desmet 77/13 (GENT)
Reynders & Sabulao 60
(GENT)
Muasya 984 (EA, K;
Muasya et al., 2002)
Goetghebeur 10201 (GENT)
Larridon et al. 2009-0033
(GENT)
Goetghebeur 10202 (GENT)
Farjon 217 (GENT)
Van den Eynden 213
(GENT)
Larridon et al. 2009-0076
(GENT)
Kilian & Lobin 6848
(GENT)
Fosberg 47227 (GENT)
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126
112
I. LARRIDON ET AL.
Table 2. Continued
Taxon
Voucher (herbarium)
Origin
ETS1f
trnH-psbA
rpl32-trnL
Cyperus papyrus L.
Cyperus pectinatus Vahl
Goetghebeur 5866 (GENT)
Larridon et al. 2010-0265
(GENT)
Porembski 624 (GENT)
Samain 2005-001 (GENT)
Shaw 890 (K*)
Unknown s.n. (GENT)
Laegaard 15909 (GENT)
Goetghebeur 5965 (GENT)
Goetghebeur 4908 (GENT)
Muasya & Muthama 1247
(EA)
BG 20051035G (GENT)
BG Ghent
Madagascar
HQ705962
HQ705936
HQ705830
HQ705810
HQ705892
HQ705869
Ivory Coast
Kenya
Hong Kong (China)
Ecuador
Zimbabwe
BG Ghent
Cameroon
Kenya
HE993980
HE993981
HQ705963
HE993982
HE993983
HE993985
HE993984
HQ705953
HE993915
HE993916
HQ705831
HE993917
HE993918
HE993920
HE993919
HQ705822
HE993705
HE993706
HQ705893
HE993707
HE993708
HE993710
HE993709
HQ705883
BG Poznan, BG
Ghent
Madagascar
HE993986
HE993921
HE993711
HQ705955
HQ705824
HQ705885
Madagascar
HQ705956
HQ705825
HQ705886
South Africa
Kenya
South Africa
Philippines, BG
Ghent
BG Ghent
Kenya
HQ705902
HQ705901
HE993987
HE993988
HQ705784
HQ705783
–
HE993922
HQ705839
HQ705838
HE993712
HE993713
HE993989
HE993990
–
HE993923
HE993714
HE993715
Cyperus
Cyperus
Cyperus
Cyperus
Cyperus
Cyperus
Cyperus
Cyperus
pustulatus Vahl
rigidifolius Steud.
rotundus L.
rubiginosus Hook.f.
rupestris Kunth
sp.
sphacelatus Rottb.
spiralis Larridon
Cyperus strigosus L.
Cyperus waterloti Cherm.
Cyperus waterloti Cherm.
Ficinia gracilis Schrad.
Isolepis fluitans (L.) R.Br.
Kyllinga alata Nees
Kyllinga brevifolia Rottb.
Kyllinga bulbosa P.Beauv.
Kyllinga chlorotropis Steud.
Kyllinga nemoralis
(J.R.Forst. & G.Forst.)
Dandy ex Hutch. &
Dalziel
Kyllinga odorata Vahl
Kyllinga polyphylla Willd.
ex Kunth
Kyllinga pulchella Kunth
Lipocarpha albiceps Ridl.
Lipocarpha chinensis
(Osbeck) J.Kern
Lipocarpha comosa
J.Raynal
Lipocarpha filiformis (Vahl)
Kunth
Lipocarpha kernii
(Raymond) Goetgh.
Lipocarpha micrantha
(Vahl) G.C.Tucker
Lipocarpha nana (A.Rich.)
Cherm.
Lipocarpha rehmannii
(Ridl.) Goetgh.
Lipcarpha salzmaniana
Steud.
Pycreus africanus
(S.S.Hooper) Reynders
Pycreus alleizettei Cherm.
Pycreus bipartitus (Torr.)
C.B.Clarke
Larridon et al. 2010-0010
(GENT)
Larridon et al. 2010-0043
(GENT)
Muasya 2713 (BOL)
Muasya & Knox 3195 (EA)
Acocks 22902 (BR)
Reynders and Sabulao 68
(GENT)
Goetghebeur 11989 (GENT)
Muasya & Gerhke 2606
(EA)
Goetghebeur 11518
(GENT)
Philippines, BG
Ghent
HQ705965
HQ705832
HQ705895
Strong 3485 (GENT)
Beeckman Z35 (GENT)
USA
Congo
HE993991
HE993992
HE993924
HE993925
HE993716
HE993717
Muasya & Knox 991 (EA)
Hess 52/195 (GENT)
Reynders & Sabulao 26A
(GENT)
Mincier 1027 (GENT)
Kenya
Angola
Philippines
–
HE994025
HE994029
HE993926
HE993944
HE993948
HE993718
HE993748
HE993752
Zambia
HE994028
HE993947
HE993751
Vanden Berghen 7913a
(GENT)
Laegaard 21195 (GENT)
Senegal
HE994030
HE993949
HE993753
Burkina Faso
HE994026
HE993945
HE993749
Luceño 186 (GENT)
Brazil
HE994032
HE993951
–
Larridon et al. 2010-0041A
(GENT)
Larridon et al. 2010-0320
(GENT)
Luceño 28 (GENT)
Madagascar
HE994031
HE993950
HE993754
Madagascar
HE994027
HE993946
HE993750
Brazil
HE994033
HE993952
–
Leeuwenberg 8527 (GENT)
Congo
HE993994
HE993927
–
Larridon et al. 2010-0299
(GENT)
Goetghebeur 11990 (GENT)
Madagascar
HE993993
–
HE993719
BG Ghent
HE993995
HE993928
HE993720
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126
C4 CYPERUS PHYLOGENY (CYPERACEAE)
113
Table 2. Continued
Taxon
Voucher (herbarium)
Origin
ETS1f
trnH-psbA
rpl32-trnL
Pycreus capillifolius
(A.Rich.) C.B.Clarke
Pycreus cataractarum
C.B.Clarke
Pycreus elegantulus (Steud.)
C.B.Clarke
Pycreus fibrillosus (Kük.)
Cherm.
Pycreus flavescens (L.)
P.Beauv. ex Rchb.
Pycreus flavescens (L.)
P.Beauv. ex Rchb. subsp.
microglumis Lye
Pycreus flavidus (Retz.)
T.Koyama (Py021)
Pycreus gracillimus Chiov.
Pycreus intactus (Vahl)
J.Raynal
Cyperus ‘Pycreus’
juncelliformis Peter &
Kük.
Pycreus longistolon (Peter &
Kük.) Napper
Pycreus macranthus
(Boeck.) C.B.Clarke
Pycreus macrostachyos
(Lam.) J.Raynal
Muasya & Knox 999 (EA)
Kenya
HE993996
–
HE993721
De Wilde 1452 (GENT)
Cameroon
HE993997
–
HE993722
Unknown 348 (GENT)
Kenya
HE993998
HE993929
HE993723
Schmitz 7479 (GENT)
Congo
HE994005
–
HE993729
Goetghebeur 10224 (GENT)
BG Ghent
HE993999
HE993930
HE993724
Malaisse & Goetghebeur
390 (GENT)
Congo
HE994000
HE993931
–
Reynders & Sabulao 45
(GENT)
Lewalle 2112 (GENT)
Reid 609 (GENT)
Philippines
HE994001
HE993932
HE993726
Burundi
South Africa
HE994002
HE994003
HE993933
–
–
HE993727
Malaisse & Goetghebeur
409 (GENT)
Congo
HE994004
–
HE993728
Muasya & Knox 1027 (EA)
Kenya
HE994006
HE993934
HE993730
Edwards 1038 (GENT)
South Africa
HE994007
–
HE993731
Muasya with Kirika,
Obunyali & Musili 2471
(EA)
Goetghebeur 4826 (GENT)
Kenya
HE994008
HE993935
HE993732
Argentina
HE994009
–
HE993733
Richards 8409 (GENT)
Robinson 3478 (GENT)
Congo
Zambia
HE994010
HE994011
HE993936
–
–
HE993734
Robinson 2310 (GENT)
Muasya & Knox 1018 (EA)
Unknown 368 (GENT)
Zambia
Kenya
Kenya
HE994012
HE994013
HE994014
–
HE993937
–
HE993735
HE993736
HE993737
Muasya & Knox 940 (EA)
Tanzania
HE994015
HE993938
HE993738
Milne-Redhead & Taylor
9184 (GENT)
Muasya & Muthama 1263
(EA)
Goetghebeur 11519 (GENT)
Tanzania
HE994016
–
HE993739
Kenya
HE994017
HE993939
HE993740
South Africa, BG
Ghent
BG Ghent
HQ705966
HQ705833
HQ705896
–
–
HE993741
Kenya
HE994018
–
HE993742
Congo
HE994020
HE993940
HE993744
Madagascar
HE994019
–
HE993743
Kenya
–
HE993941
HE993725
Pycreus megapotamicus
(A.Dietr.) Nees
Pycreus melanacme Nelmes
Pycreus melas (Ridl.)
C.B.Clarke
Pycreus micromelas Lye
Pycreus mundtii Nees
Pycreus nigricans (Steud.)
C.B.Clarke
Pycreus nuerensis (Boeck.)
S.S.Hooper
Pycreus pauper (Hochst. ex
A.Rich.) C.B.Clarke
Pycreus pelophilus (Ridl.)
C.B.Clarke
Pycreus polystachyos
(Rottb.) P.Beauv.
Pycreus polystachyos
(Rottb.) P.Beauv. subsp.
holocericeus (Link)
T.Koyama
Pycreus pumilus (L.) Nees
Pycreus reductus Cherm.
017
Pycreus reductus Cherm.
046
Pycreus rehmannianus
C.B.Clarke
Reynders and Sabulao 64
(GENT)
Muasya & Muthama 1264
(EA)
Dhondt 11 (GENT)
Larridon et al. 2010-0161
(GENT)
Muasya & Knox 1022 (EA)
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126
114
I. LARRIDON ET AL.
Table 2. Continued
Taxon
Voucher (herbarium)
Origin
ETS1f
trnH-psbA
rpl32-trnL
Pycreus rhizomatosus
C.B.Clarke
Pycreus sanguinolentus
(Vahl) Nees
Pycreus smithianus (Ridl.)
C.B.Clarke
Pycreus xantholepis Nelmes
Queenslandiella hyalina
(Vahl) Ballard
Remirea maritima Aubl.
Gereau & Dumetz 3259
(GENT)
Kwika & Mundi 21
(GENT)
Reekmans 7531 (GENT)
Madagascar
HE994021
HE993942
–
Kenya
HE994022
–
HE993745
Burundi
HE994023
HE993943
HE993746
Reekmans 9809 (GENT)
Muasya 2490 (EA)
Burundi
Kenya
HE994024
HQ705967
–
HQ705834
HE993747
HQ705897
Faden et al. 96/48 (K*;
Muasya et al., 2002)
Goetghebeur 11520 (GENT)
Tanzania
HQ705968
HQ705835
HQ705898
BG Porto, BG Ghent
HQ705900
HQ705782
HQ705837
Tanzania
HQ705969
HQ705836
HQ705899
Namibia
HE994034
HE993953
HE993755
Scirpoides holoschoenus (L.)
Soják
Sphaerocyperus erinaceus
(Ridl.) Lye
Volkiella disticha Merxm. &
Czech
Faden et al. 96/358 (K*;
Muasya et al., 2002)
Müller & Giess 493
(GENT)
Alignments are available from the first author on
request.
Phylogenetic hypotheses were produced using
maximum likelihood (ML) and Bayesian inference
(BI) analyses. All analyses were first performed on
the single-marker datasets (ETS1f, rpl32-trnL, trnHpsbA). As no conflicting clades with a significant confidence value were revealed, a combined dataset was
constructed and analysed. The latter was subdivided
into three partitions, corresponding to the single
markers. The program RAxML v7.2.8 (Stamatakis,
2006) was used to execute the Rapid Bootstrapping
algorithm for 500 replicates combined with an ML
search, using the GTRCAT model (Stamatakis,
Hoover & Rougemont, 2008). Model parameters were
optimized for each partition when analysing the combined dataset.
Bayesian phylogenetic (BI) analyses were carried
out in MrBayes v3.1.2 (Ronquist & Huelsenbeck,
2003). For the analysis, MrModeltest v2.3 (Nylander,
2004) was used to determine the model that best
fitted the data, applying the Akaike Information Criterion. For the combined dataset, a model was determined for each partition. This method is referred to
as the BI method. Four independent, parallel runs of
one cold and three heated chains were run for 30
million generations each. Trees and parameter estimates were saved every 1000 generations. The analyses were run on a high-performance computer at
Ghent University (Stevin Supercomputer Infrastructure, ICT Department). Convergence, associated likelihood values, effective sample size (ESS) values and
burn-in values of the different runs were verified with
Tracer v1.5 (Rambaut & Drummond, 2007). Calcula-
tion of the consensus tree and the posterior probability (PP) of clades was based on the trees sampled
after the chains converged. Trees were drawn using
FigTree v1.3.1 and Adobe Photoshop CS3.
RESULTS
SEQUENCE
ALIGNMENTS
After alignment and application of Gblocks v0.91b
(Castresana, 2000), the ETS1f alignment included
105 sequences of 953 bases, the rpl32-trnL alignment
94 sequences of 1334 bases and the trnH-psbA alignment 81 sequences of 1364 bases. The concatenated
dataset included 108 sequences and the Gblocks
program retained 57%, or 2101 characters, of the
original alignment. Most excluded regions came from
the ETS1f region.
PHYLOGENETIC
ANALYSIS
The three single-locus ML analyses revealed nearly
identical topologies and bootstrap values. As expected, the clades supported by single-locus analyses
received greater support in the multi-locus ML
analysis. In the various analyses, only minor conflicts concerning the position of some C4 Cyperus
spp. in the backbone of the C4 Cyperus clade were
detected. Most nodes in the backbone of this clade
had little or no support.
The three single-locus BI analyses did not differ
significantly in tree topologies. The multi-locus BI
topologies did not differ from the multi-locus ML tree,
except for some of the C4 Cyperus spp. in the main
polytomy, as mentioned above for the ML analyses.
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126
C4 CYPERUS PHYLOGENY (CYPERACEAE)
Evaluation of the multi-locus BI analysis output
showed that the four runs converged on similar log
likelihood (–23 908) and parameter values. The
burn-in value for all runs was determined at three
million generations. ESS for the likelihood value of
the combined runs consisted of 1397.38 uncorrelated
samples.
Figure 3 shows the 50% majority consensus multilocus BI tree with the associated PP values and the
bootstrap values of the multi-locus ML tree. Only
bootstrap values above 75% and PPs above 0.85 are
shown.
DISCUSSION
WITH C3 CYPERUS
AFFINITIES
In Cypereae, the Cyperus clade is sister to the Ficinia
clade, here used as outgroup represented by species of
Scirpoides, Isolepis and Ficinia (Fig. 3). The Cyperus
clade is strongly supported as monophyletic, but
includes several lineages which are currently recognized at the generic level. As in Larridon et al.
(2011a), C3 Cyperus spp. form a grade at the base of
Cyperus (Fig. 3; Table 3). The clade sister to the C4
Cyperus clade is formed by Cyperus section Leucocephali Cherm. ex Kük. sensu Larridon et al. (2011b)
(Fig. 3). Although the species of this section use C3
photosynthesis (e.g. Bruhl & Wilson, 2007; Larridon
et al., 2011a), they occur in open grassland habitats
which are generally dominated by species using C4
photosynthesis. This suggests that the species of
Cyperus section Leucocephali have characters (e.g.
geophytic hemicryptophtes, resprouting immediately
at the start of the wet season and dying back on onset
of the dry season, photosynthesis at high temperatures and irradiation) which make them fitter to
survive in these habitats than most other C3 Cyperus
spp.
C4 CYPERUS
RADIATION
Our molecular phylogenetic hypothesis shows very
short branch lengths for most of the C4 Cyperus clade
when compared with the C3 Cyperus grade and the
deepest nodes of the C4 Cyperus clade, suggesting a
rapid diversification of the clade. Endress (2011: 370)
wrote: ‘Many structural innovations originated in
several clades [of angiosperms] and in special cases
could become key innovations, which likely were
hotspots of diversification’. The evolution of C4 photosynthesis in Cypereae can be considered as a key
innovation, being the cause of a burst of speciation as
a result of: (1) increased fitness in drier habitats
(Besnard et al., 2009); (2) optimized nitrogen uptake;
and (3) improved resistance to higher irradiance, fire
and chemical stress caused by salt and heavy metals
115
(Li, Wedin & Tieszen, 1999; Stock, Chuba & Verboom,
2004). Based on our results and on literature and
herbarium data on the distribution of species, we
hypothesize that the evolution of the C4 photosynthetic pathway in Cypereae occurred in East Africa.
This region, particularly present-day Tanzania, is the
centre of diversity for C4 Cyperus spp. In addition, all
segregate lineages and most sections are represented
in the East African flora. Outside Africa, the Cyperus
clade is either represented by widespread species or
by taxa which evolved locally as a result of smaller
radiations originating from dispersal events.
AFFINITIES
IN
C4 CYPERUS
The basal nodes
Several early branches of the C4 Cyperus clade are
strongly supported (Fig. 3). The first subclade, also
retrieved in previous studies (e.g. Muasya et al., 2002,
in press; Larridon et al., 2011a), is represented by
Cyperus cuspidatus Kunth (and its Malagasy relative
C. waterlotii Cherm.). Kükenthal (1935–36) placed
the species of this clade in Cyperus section Amabiles
C.B.Clarke. Although homogeneous, this section is
only held together by characters which probably represent the plesiomorphic condition in C4 Cyperus,
such as spikelets arranged in digitate clusters (as in
many C3 Cyperus spp. vs. generally spikes of spikelets
in C4 Cyperus) and multi-nerved glumes with an
excurrent mucro. Species of Cyperus sections Amabiles, Aristati Nees and Rupestres C.B.Clarke show
similar characters. After the C. cuspidatus clade, the
next branches of our molecular phylogenetic hypothesis include species of the segregates Alinula
J.Raynal, Ascolepis Nees, Lipocarpha R.Br., Queenslandiella Domin and Volkiella Merxm. & Czech, and
of Cyperus section Rupestres (i.e. C. rupestris Kunth
and C. meeboldii Kük.). The relationship between the
two species of Cyperus section Rupestres is strongly
supported in our analysis. Taxonomically, this section
is well circumscribed by several synapomorphies,
such as swollen stem bases and a tendency to reduced
flowers, each with a single stigma branch and a
single stamen. The exact position of its corresponding
clade remains to be confirmed, but its position among
the early branches of the C4 Cyperus clade seems
acceptable.
Queenslandiella
The monotypic Queenslandiella is currently recognized as a separate genus, based on its laterally
flattened, dimerous gynoecia and its deciduous spikelets. Queenslandiella has multi-nerved glumes with
an excurrent mucro, suggesting that it is an early
branching lineage of C4 Cyperus (Fig. 3). When dried,
it has a strong curry odour, a character it shares with
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126
116
I. LARRIDON ET AL.
Figure 3. Phylogenetic hypothesis for the Cyperus clade: 50% majority consensus multi-locus Bayesian inference (BI)
tree with the associated posterior probability (PP) values and the bootstrap values of the multi-locus maximum likelihood
(ML) tree. Only bootstrap values > 75% and posterior probabilities > 85% are shown.
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126
C4 CYPERUS PHYLOGENY (CYPERACEAE)
117
Alinula
According to the current circumscription, Alinula
includes four species (Goetghebeur, 1998; Govaerts
et al., 2012). Only one species, Alinula paradoxa
(Cherm.) Goetgh. & Vorster, is included in this study
(Fig. 3). From a morphological point of view, this
species differs significantly from the other three. In our
opinion, the current circumscription of Alinula does
not represent a natural group. Haines & Lye (1983),
who treated Alinula as a subgenus in Cyperus,
included A. paradoxa in Cyperus subgenus Fimbricyperus Lye separate from the other Alinula spp. In our
molecular phylogenetic hypothesis, A. paradoxa clusters among the early branches of the C4 Cyperus clade.
More research is needed to reveal its exact relationships. Alinula lipocarphioides (Kük.) J.Raynal has
been shown to be closer to Lipocarpha (Muasya et al.,
2009a, in press).
University, Gent, unpubl. data). Lipocarpha appears
to be paraphyletic, including Ascolepis and Volkiella
(Fig. 3). The first diverging branch is formed by
Lipocarpha kernii (Raymond) Goetgh. and L. rehmannii (Ridl.) Goetgh. (Fig. 3), formerly placed in a
separate genus Rikliella J.Raynal. Although these
species strongly resemble Lipocarpha, prophyll and
glumes have not been observed around the flower.
Therefore, Goetghebeur & Van den Borre (1989)
interpreted Rikliella as a highly evolved lineage of
Lipocarpha. However, on the basis of our phylogenetic trees, it is unclear whether the partial inflorescences should be interpreted as pseudospikelets
or as true spikelets with spiral glumes (which occur
in at least three other lineages of the Cyperus clade;
Muasya et al., in press). Sister to this clade is a
clade comprising Ascolepis and Lipocarpha s.s.
(Fig. 3). Ascolepis spikelets are characterized by a
single large glume subtending a flower and the loss
of the spikelet prophyll. In Lipocarpha s.s., the first
branching clade is formed by L. micrantha (Vahl)
G.C.Tucker (Fig. 3), which is characterized by a
reduction of the glume. This clade is followed by the
rest of Lipocarpha s.s., which also includes the
monotypic Volkiella (Fig. 3). Volkiella possesses both
a spikelet prophyll and a glume, and is included in
a subclade with L. albiceps Ridl. and L. comosa J.
Raynal (Fig. 3). These two Lipocarpha spp. are characterized by a well-developed, firm and often darkcoloured prophyll which falls off the rachis
separately from the flower and its glume. In other
Lipocarpha spp., the prophyll is hyaline and falls off
together with the nutlet and glume. Volkiella shares
the more rigid prophyll with the two abovementioned species. Volkiella disticha Merxm. &
Czech is, in many aspects, a special, highly derived
species differing from Lipocarpha by the distichous
arrangement of the spikelets on the rachis. A more
elaborate study of Lipocarpha, integrating molecular
phylogeny and morphology, will be presented in
another paper (K. Bauters et al., Ghent University,
Gent, unpubl. data).
Ascolepis–Lipocarpha clade
A well-supported clade in our molecular phylogenetic
hypothesis includes the genera Ascolepis, Lipocarpha
and Volkiella (Fig. 3), which are all characterized by
strongly reduced deciduous spikelets grouped into
pseudospikelets (spikes of spikelets). Our results
confirm that Ascolepis and Lipocarpha are closely
related, as already observed by Muasya et al. (2002).
Their relatively early branching position in C4
Cyperus is corroborated by the presence of a small,
weakly differentiated Cyperus-type embryo, which is
also common in C3 Cyperus and in the early
branches of the Ficinia clade (M. Reynders, Ghent
The hard polytomy
The vast majority of C4 Cyperus spp. are included in
an unresolved polytomy (Fig. 3), which can also be
found in all previous molecular phylogenetic studies
(e.g. Muasya et al., 2002, 2009a, b). As it has not been
possible to resolve this polytomy, even when using
fast mutating plastid and nuclear markers, additional
markers need to be tested, as well as other techniques
based on next-generation sequencing (e.g. Harrison &
Kidner, 2011). However, in our molecular phylogenetic study, several subclades and the relationships
between some taxa are strongly supported (Fig. 3).
These taxa are discussed below.
Table 3. C3 Cyperus species included in the phylogeny
and the sections they represent
Species
Section
Cyperus haspan
Cyperus section Haspani
(Kunth) C.B. Clarke
Cyperus section Luzuloidei
(Kunth) C.B. Clarke
Cyperus section Anosporum
(Nees) Pax
Cyperus section Alternifolii
(Kunth) C.B. Clarke
Cyperus section Leucocephali
Cherm. ex Kük.
Cyperus luzulae
Cyperus pectinatus
Cyperus alternifolius
and C. marginatus
Cyperus spiralis
C. squarrosus L., another species showing many of
the presumed plesiomorphic characters of the clade.
Cyperus squarrosus falls among the basal nodes in an
internal transcribed spacer (ITS) analysis of Cyperus
(C.S. Reid, Louisiana Department of Wildlife and
Fisheries, Baton Rouge, unpubl. data).
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126
118
I. LARRIDON ET AL.
Table 4. Comparison between the noncore Pycreus species and the core Pycreus clade (with the exception of Cyperus
laevigatus)
Character
Noncore species
Core Pycreus clade
Glumes
Mucro
Anthela
Multi-nerved
Usually present, excurrent
Well-developed with long and narrow spikelets,
often with second-order branches
Isodiametric
Mostly opportunistic and lowland concentrated
Widespread and common on roadsides and rice
fields
Midrib with only three nerves
Not present or rarely shortly excurrent
Often condensed or reduced, especially in
therophytic species
Isodiametric to strongly elongate
Often very specialized
Narrow distribution, occurring in
high-altitude bogs, salt marshes,
floating on open water, etc.
Nutlet epidermal cells
Ecology
Distribution and habitat
C4 Cyperus s.s.
One subclade of C4 Cyperus s.s. which is strongly
supported in our molecular phylogenetic hypothesis
(Fig. 3) contains species belonging to Cyperus sections
Papyrus (Willd.) Thouars (C. papyrus L., C. dives
Delile, C. alopecuroides Rottb.) and Rotundi
C.B.Clarke (C. rotundus L., C. longus L., C. endlichii
Kük., C. rigidifolius Steud.). These species are all
characterized by a narrowly to broadly winged
rachilla with deciduous or persistent wings. Several
other sections which are not represented in the
current analysis, i.e. Cyperus sections Brevifoliati
C.B.Clarke, Exaltati (Kunth) C.B.Clarke and Fastigiati Kük., share these characters. Cyperus compressus
L. (Cyperus section Compressi Nees) also clusters in
this clade (Fig. 3).
Kyllinga
Kyllinga Rottb. forms a strongly supported monophyletic clade (Fig. 3). There is weak support for the
Kyllinga clade as sister to a clade including C. iria L.,
C. croceus Vahl and C. fulgens C.B.Clarke. Kyllinga is
delimited by the combination of a head-like inflorescence, deciduous spikelets and laterally flattened gynoecia. Three subclades can be recognized in the current
molecular phylogenetic hypothesis (Fig. 3). A detailed
molecular phylogenetic study of Kyllinga, including
amplified fragment length polymorphism (AFLP) data,
is being prepared (W. Huygh et al., Ghent University,
Gent unpubl. data).
Remirea and Sphaerocyperus
The monotypic genera Remirea Aubl. and Sphaerocyperus Lye remain unresolved in C4 Cyperus (Fig. 3).
Both taxa are characterized by a series of empty scales
below the flower-bearing glume. For this reason, affinities with Schoeneae or Rhynchosporeae have been
suggested (Fenzl, 1836: 144; Bentham, 1883: 1038;
Ridley, 1884: 165; Pax, 1888: 116; Baillon, 1894: 377;
Clarke, 1901–02: 267; Kükenthal, 1944: 200–209). In
addition, Remirea has corky rachilla internodes.
Pycreus
Pycreus P.Beauv. is here retrieved as a paraphyletic
entity including several Cyperus spp. (Fig. 3). In
Pycreus, relationships are poorly resolved, although
good resolution is obtained for some smaller clades of
related species. Furthermore, one large clade is well
supported and contains the majority of the sections
and species in addition to C. laevigatus L. (Fig. 3).
This clade is referred to as the ‘core Pycreus clade’.
The Pycreus species which are not included in the
core Pycreus clade all belong to four of Kükenthal’s
(1935–36) sections, namely Cyperus section Albomarginati Kük., Cyperus section Lancei Kük., nom.
superfl., Cyperus section Polystachyi (C.B.Clarke)
Kük., nom. illeg., Cyperus section Pumili Kük. and
Cyperus section Rhizomatosi Kük. Their mutual relationships remain unresolved, but their position
outside the core Pycreus clade can be justified as the
species in these sections possess plesiomorphic characters in contrast with the species in the core Pycreus
clade (Table 4).
Among the early branching lineages, two smaller
clades are well supported (Fig. 3). Pycreus longistolon
(Peter & Kük.) Napper and P. macrostachyos (Lam.)
J.Raynal are strongly supported together. Kükenthal
(1935–36) classified P. longistolon in Cyperus section
Lancei, nom. superfl., a section which appears to be
artificial as the species only share rather large and
dark glumes. Pycreus macrostachyos was included in
Cyperus section Albomarginati [as C. albomarginatus
(Mart. & Schrad. ex Nees) Steud.]. The inclusion of
P. longistolon in Cyperus section Albomarginati seems
to be appropriate in view of the overall habit of the
plants (except for the stolons), the large dimensions of
th e spikelets, glumes and nutlets, and the wide,
hyaline glume margins. However, the last character is
less conspicuous than in P. macrostachyos.
Another well-resolved subclade corresponds to
Cyperus section Polystachyi, nom. illeg., and is characterized by typically elongated nutlets and a winged
rachilla. Pycreus pelophilus C.B.Clarke is an excep-
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126
C4 CYPERUS PHYLOGENY (CYPERACEAE)
tion in having broad nutlets. Nevertheless, it was
placed in this section by Kükenthal (1935–36) and
this relationship is confirmed here (Fig. 3).
The strongly supported inclusion of C. aterrimus
(Fig. 3) in the early branching lineages of Pycreus is
noteworthy as this species has triangular nutlets, a
different inflorescence and overall larger dimensions
of the glumes and nutlets compared with Pycreus.
Cyperus aterrimus Hochst. ex Steud. is strongly
supported as sister to P. nuerensis (Boeckeler)
S.S.Hooper, which it resembles in its growth form,
dark-coloured inflorescence and Afromontane distribution. Cyperus kerstenii Boeckeler and C. congestus
Vahl also appear to be associated with the early
branching Pycreus lineages, although without
support. We found no morphological characteristics
to support this relationship, especially as both
species have deciduous glumes, a character which
does not occur in Pycreus. The presence of species
with triangular nutlets in Pycreus suggests a reversion of the dimerization of the gynoecium. Recently,
Vrijdaghs (2006) and Reynders et al. (2012) showed
that gynoecia in Cyperoideae originate from an
annular primordium on which stigma primordia
originate. This offers more flexibility for the positioning of stigma branches with respect to the
restrictions previously assumed based on the anatomical studies by Blaser (1941a, b).
The core Pycreus clade only includes Pycreus spp.,
except for C. juncelliformis Peter & Kük. and C. laevigatus. Cyperus juncelliformis is a true Pycreus,
but its name has never been combined into Pycreus.
Therefore, its name is mentioned as ‘Pycreus’ juncelliformis in Figure 3. The association of C. laevigatus with the core Pycreus clade seems to be
strong. It was verified by including three separate
samples of C. laevigatus, and this relationship also
occurred in the analyses of the three markers separately (M. Reynders, Ghent University, Gent,
unpubl. data). Whereas Pycreus is characterized by
laterally flattened dimerous gynoecia, C. laevigatus
has dorsiventrally flattened dimerous gynoecia. This
might represent either an intermediate state
between a trimerous Cyperus ancestor and Pycreus
or a derived state from a Pycreus ancestor. Moreover, the vascularization pattern in the rachilla of
C. laevigatus differs from the pattern in rachillas of
several Pycreus spp. studied by Vrijdaghs et al.
(2011). Shared characters of C. laevigatus and
Pycreus are the rather glossy glumes and their
ecology.
ETS1f sequences of the species in the core Pycreus
clade (except C. laevigatus) show a large duplication
of 140 bp, which is a strong additional argument
that this represents a natural group. In the core
Pycreus clade, several species clusters are resolved
119
(Fig. 3). Pycreus flavidus (Retz.) T.Koyama clusters
with ‘Pycreus’ juncelliformis, corresponding to
Kükenthal’s (1935–36) Cyperus section Globosi
(C.B.Clarke) Kük. The inclusion of P. niger (Ruiz &
Pav.) Cufod. is morphologically supported by the
similar nutlets and the shape of the glumes. In contrast, the inclusion of P. flavescens (L.) P.Beauv. ex
Rchb. ssp. microglumis Lye is remarkable and needs
further investigation. Morphologically, the species
cluster of P. capillifolius (A.Rich.) C.B.Clarke and
P. reductus Cherm. shows resemblances to Cyperus
section Globosi, but this relationship remains unresolved in the current study. In addition, species of
Cyperus section Sulcati Kük., nom. illeg., are distributed between two clades, although the species of
this section all share peculiar glumes with a furrow
on both sides. Pycreus sanguinolentus (Vahl) Nees
and P. bipartitus (Torr.) C.B.Clarke are smaller representatives of this section, whereas P. mundtii Nees
and P. megapotamicus (A.Dietr.) Nees are taller
plants with long culms with spaced leaves that form
floating mats on open water. The clustering of
P. melanacme Nelmes with this section needs
further investigation, as this is, in many ways, a
rather distinct therophytic species.
Pycreus africanus (S.S.Hooper) Reynders, P. smithianus (Ridl.) C.B.Clarke, P. cataractarum C.B.Clarke,
P. fibrillosus (Kük.) Cherm. and P. gracillimus Chiov.
form a well-resolved clade. Pycreus africanus belongs
to Pycreus section Tuberculati Cherm. (Reynders &
Goetghebeur, 2010). Pycreus smithianus and P. cataractarum share many characters, such as a contracted inflorescence, straight rachilla, bright white
glumes and a Guineo-Congolean distribution, with a
preference for habitats by running water. Kükenthal
(1935–36) included both species in Cyperus section
Propinqui (C.B.Clarke) Kük. Pycreus fibrillosus and
P. gracillimus both have a plant base covered with
fibrous remains of old leaf sheaths, an inflorescence
reduced to only a few spikelets, a flexuous rachilla
and a Zambesian distribution in Afromontane habitats. These species were placed in Cyperus section
Propinqui and Cyperus section Latespicati Kük.,
respectively, by Kükenthal (1935–36) based on their
pale vs. dark glumes. As this character seems to
depend on altitude (many species of Cyperus s.l.
growing above 2000 m have dark-coloured glumes), it
is not considered as reliable for sectional delimitation.
Therefore, these two sections are likely to be
polyphyletic.
A final strongly supported clade contains species
belonging to Cyperus section Latespicati (P. alleizettei
Cherm.) and Cyperus section Flavescentes Kük.
(P. flavescens, P. rehmanianus C.B.Clarke) sensu
Kükenthal (1935–36). Pycreus xantholepis Nelmes, a
tall therophyte, shares its yellow glume colour and
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126
120
I. LARRIDON ET AL.
nutlet shape with P. alleizettei and P. flavescens. The
inclusion of P. melas (Ridl.) C.B.Clarke [Cyperus
section Globosi] needs further investigation, as this
species is morphologically distinct.
RE-EVALUATION
OF THE GENERIC STATUS OF THE
SEGREGATE LINEAGES
In this section of the paper, we re-evaluate the generic
status of the segregate lineages based on the currently available knowledge about these taxa. This is a
combination of morphological, anatomical, ontogenetic and embryographical data, and the results of
previous and current molecular phylogenetic studies.
Alinula
Goetghebeur & Vorster (1988) included four species in
this genus. A species from eastern Africa was originally described as Ficinia lipocarphioides Kük. based
on the presence of a hypogynous disc around the base
of the fruit. However, after studying its inflorescence
morphology and chlorocyperoid anatomy, Raynal
(1973) hypothesized that the species was intermediate between Ascolepis and Mariscus Vahl, and eventually placed it in a new genus Alinula (Raynal,
1977). Three more species were added to Alinula,
after a complex taxonomical trajectory (e.g.
Goetghebeur, 1977; Goetghebeur & Vorster, 1988;
Haines & Lye, 1983). In our opinion, the current
circumscription of Alinula does not represent a
natural group, although A. lipocarphioides, A. malawica (J.Raynal) Goetgh. & Vorster and A. peteri
(Kük.) Goetgh. & Vorster show clear morphological
affinities, such as the presence of pseudospikelets.
However, as pseudospikelets also occur in other, more
distantly related taxa of Cypereae (e.g. Ascolepis and
Lipocarpha), their presence is, in our opinion, insufficient for generic delimitation. Moreover, A. lipocarphioides has been shown to be nested in the
Lipocarpha clade (Muasya et al., in press).
Ascolepis
The head-like inflorescence of Ascolepis consists of
clusters of single-flowered spikelets, sometimes with
a rudimentary second glume. Typically, the spikelet
prophyll does not develop, but the only glume subtending the single flower is always well developed and
larger than the bract which subtends the spikelet. In
other species, the glume encloses the flower completely and wings are often developed, possibly for
wind dispersal. In other species, the glume is strongly
elongated and/or brightly coloured, which gives the
inflorescence heads an Asteraceae-like appearance
(e.g. as in Ascolepis protea Welw.), suggesting insect
pollination. Raynal (1973) postulated the origin of
Ascolepis from a mariscoid ancestor. However,
Goetghebeur (1980) argued that, although glume and
nutlet are shed together in Ascolepis, the rachilla
remains fixed on the rachis in contrast with Mariscus.
Mariscus was an artificial genus grouping together
members of Cypereae with deciduous spikelets. Our
results concur with Muasya et al. (2002) in resolving
Ascolepis and Lipocarpha as sister taxa. Morphological differentiation in these two taxa shows that
similar functional inflorescences originated in both
groups using different organs (e.g. As. protea vs.
L. comosa). In Lipocarpha, the spikelet bract is
strongly developed, whereas the glume subtending
the flower is reduced. In Ascolepis, the spikelet bract
is rudimentary, whereas the glume subtending the
flower is strongly developed. Because of the morphological diversity of the inflorescence, rachilla and
glumes among the different subgroups in Ascolepis,
Goetghebeur (1986) considered the possibility that
Ascolepis is a complex of convergent lineages which
developed a similar inflorescence Bauplan. A more
thorough molecular investigation of Ascolepis is
needed to test the monophyly of this taxon.
Kyllinga
Kyllinga is characterized by the combination of laterally flattened gynoecia, deciduous spikelets with a
reduced number of flowers and capitate inflorescences. The close relationship of Kyllinga with
Cyperus has always been acknowledged, and various
authors have treated Kyllinga at the subgeneric level
in Cyperus (e.g. Kükenthal, 1935–36; Haines & Lye,
1983). However, Kyllinga has always been considered
as a homogeneous, natural entity, as illustrated by
the fact that several authors have maintained
Kyllinga as a separate genus whilst lumping Mariscus, Pycreus, Torulinium Desv. ex Ham. and Juncellus
C.B.Clarke in Cyperus (Lye, 1972, 1982; Tucker,
1983). The monophyly of Kyllinga is confirmed by our
results, where it is retrieved as a strongly supported
clade (Fig. 3). As (1) Kyllinga is nested in C4 Cyperus,
(2) capitate inflorescences with reduced, deciduous
spikelets (i.e. pseudospikelets) are encountered in
various lineages in C4 Cyperus, such as Cyperus
section Bulbocaules (C.B.Clarke) Kük., Ascolepis,
Lipocarpha and Remirea, and (3) laterally flattened
gynoecia also occur in Pycreus and Queenslandiella,
which are not immediately related, there are, in our
opinion, no sufficient arguments to warrant generic
status for Kyllinga.
Lipocarpha
Lipocarpha spp. generally have a highly specialized
inflorescence consisting of a spike of highly reduced
spikelets, with each spikelet, subtended by a bract,
containing an abaxial prophyll and an adaxial glume
subtending the flower. A few Lipocarpha spp. have
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126
C4 CYPERUS PHYLOGENY (CYPERACEAE)
lost the glume subtending the flower, although some
rudiments of it remain visible (Goetghebeur & Van
den Borre, 1989). These species were originally classified in a separate genus Hemicarpha, based on the
reduction of the glume and the presence of a pseudolateral inflorescence (Nees von Esenbeck, 1834). As
the type species of Hemicarpha Nees, H. isolepis Nees
[accepted name: L. hemisphaerica (Roth) Goetgh.],
does not show this reduction, Hemicarpha was synonymized with Lipocarpha (Goetghebeur & Van den
Borre, 1989). Lipocarpha micrantha, which belongs to
this group, is sister to all other Lipocarpha spp.
studied, including Volkiella.
Haines & Lye (1971, 1983) and Goetghebeur & Van
den Borre (1989) considered Rikliella to represent a
final reduction step of a Lipocarpha spikelet, in which
the spikelet prophyll and glume subtending the flower
are lost, resulting in a perfect pseudospikelet with
flowers in the axil of the spikelet bracts. Hemicarpha
was indicated as the transitional stage between
Lipocarpha and Rikliella. Hemicarpha and Rikliella
are no longer recognized at the generic level
(Goetghebeur & Van den Borre, 1989; Govaerts et al.,
2012). Our results place the two species of Rikliella
(L. rehmannii and L. kernii) on a separate, strongly
supported branch, and not as a specialized lineage of
Lipocarpha. This questions previous interpretations
of its inflorescence Bauplan.
As in Alinula, Ascolepis and Kyllinga, we do not
consider the presence of pseudospikelets sufficient to
warrant generic status for Lipocarpha. Furthermore,
in this study, Lipocarpha is found to be paraphyletic,
containing Ascolepis and Volkiella. A more detailed
study of Lipocarpha and Rikliella will be published
elsewhere (K. Bauters et al., Ghent University, Gent,
unpubl. data).
Pycreus
Pycreus is the largest segregate genus in C4 Cyperus.
Furthermore, it is morphologically and ecologically
diverse. The close relationship between Cyperus and
Pycreus has never been doubted, as Pycreus only
differs from Cyperus s.s. in its laterally flattened
gynoecia. These gynoecia also occur in Kyllinga and
Queenslandiella, which, in contrast with Pycreus, also
have deciduous spikelets. The generic status of these
taxa has always been controversial, and their status
strongly correlated with the taxonomic value granted
to laterally flattened gynoecia. From our results, it is
evident that taxa with laterally flatttened gynoecia
are not sister groups, and Kyllinga is strongly supported as a separate entity. Therefore, we can conclude that there have been multiple independent
origins of lateral gynoecia in Cypereae.
Our current molecular phylogenetic study includes
species representing all 13 sections of Kükenthal
121
(1935–36). Although relationships between the different sections remain poorly resolved, several patterns
require further attention. Pycreus is not monophyletic, as species that Kükenthal (1935–36)
included in Cyperus sections Albomarginati, Polystachyi, nom. illeg., Pumili and Rhizomatosi are found
in the main C4 Cyperus polytomy (Fig. 3). Many
species of these sections share several plesiomorphic
characters which also occur in C4 Cyperus, whereas
species in the core Pycreus clade show more evolved
character states (see Table 4). As in Kyllinga, we do
not consider laterally flattened gynoecia sufficient to
maintain Pycreus at the generic level, especially as it
was resolved as polyphyletic in the present study.
Queenslandiella
Queenslandiella is a third taxon nested in the C4
Cyperus polytomy, which is characterized by laterally
flattened gynoecia. It shares the open inflorescence
with Pycreus (which is the plesiomorphic condition in
C4 Cyperus). However, it has most often been considered to be related to Kyllinga, with which it shares
deciduous spikelets, and keeled and multi-nerved
glumes (Chermezon, 1919; Ballard, 1932, 1933;
Koyama, 1976). The species has always been placed
in or near Cyperus. However, even when included in
Cyperus, it was most often retained in its own section
or subgenus (Kern, 1974; Govindarajalu, 1975;
Haines & Lye, 1983).
As with the other specialized, short-lived and monotypic segregate lineages, Queenslandiella has also
accumulated many peculiar characters which isolate
it from the other C4 Cyperus taxa. These characters
include the large proportions of glumes and nutlets
compared with most other Cyperus spp., vegetative
anatomy (Govindarajalu, 1975) and embryo type (Van
der Veken, 1965). Several Cyperus spp. have been
considered to be closely related to Queenslandiella,
including C. soyauxii Boeckeler, which has similar
deciduous spikelets with similar glumes and a similar
embryo (Kükenthal, 1936; Van der Veken, 1965), but
trimerous pistils (Goetghebeur, 1986). Lye (1983)
described C. micromariscus Lye, which is only known
from its type collection in Tanzania. This plant also
has an open inflorescence with deciduous spikelets
and laterally flattened pistils comparable with
Queenslandiella, but differs in the small glumes and
nutlets and different habit. Therefore, Lye (1983)
assumed a different origin of this species and placed
it in its own Cyperus subgenus Micromariscus Lye
(Haines & Lye, 1983). The relationship of Queenslandiella to both C. soyauxii and C. micromariscus
needs further confirmation. As for the segregates
above, we do not consider the specialized characters of
Queenslandiella sufficient to warrant recognition at
the generic level.
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126
122
I. LARRIDON ET AL.
Remirea
Remirea is another monotypic entity with special
adaptations to its coastal habitat. It is characterized
by a capitate inflorescence with deciduous spikelets.
Each spikelet contains a few empty glumes at the
base and a corky rachilla which envelops the fruit.
For these reasons, it had been classified among Rhynchosporeae (Fenzl, 1836; Bentham, 1883; Pax, 1888;
Baillon, 1894; Clarke, 1901–02; Kükenthal, 1944;
Haines & Lye, 1983). However, Nees von Esenbeck
(1834) had already placed Remirea correctly in Cypereae. After Kunth (1837) gave a correct interpretation
of the spikelet, this opinion was followed by
Chermezon (1922), Kern (1958, 1974), Oteng-Yeboah
(1975), Hooper (1983) and Goetghebeur (1986, 1998).
Remirea is nested in the main C4 Cyperus polytomy,
similar to Sphaerocyperus (Fig. 3), which also has
empty glumes in the lower part of the spikelets. The
relationship between these two taxa remains unclear.
However, we do not believe empty glumes at the base
of the spikelets to be sufficient as a generic character
considering that other links with C4 Cyperus are clear.
The corky rachilla is also observed in C. odoratus L.
(formerly in the genus Torulinium), a species with
multiple flowers in which the rachilla breaks up into
individual segments. The affinity between Remirea
and C. odoratus needs further investigation.
Sphaerocyperus
The deciduous spikelets of the monotypic Sphaerocyperus have six or seven distichously arranged glumes,
only one of which bears a maturing nutlet. The sole
species has variously been placed in Actinoschoenus
Benth., Cyperus, Schoenus L. and Rhynchospora Vahl
before it was described as a separate genus Sphaerocyperus (Lye, 1972). Like Remirea, we consider the
empty glumes as insufficient to retain this taxon as a
separate genus nested in a paraphyletic Cyperus with
which it shares clear morphological affinities.
Volkiella
Volkiella is a rare monotypic taxon from southwestern Africa (mainly Namibia), and can be seen as
an extremely specialized lineage adapted to psammophytic habitats. When described, Volkiella was considered to be intermediate between Cyperus and
Lipocarpha (Merxmüller & Czech, 1953). The relationship with Lipocarpha was explained by the
similar presence of the two ‘floral scales’ (‘hypogynen
Skalen’), for which the correct interpretation is not
yet clear, but the relationship with Cyperus was
assumed on the basis of the distichous placement of
the ‘Glumae’, which are, in fact, the spikelet bracts
and thus not homologues of the glumes in Cyperus
and other sedges. This initial interpretation was followed by Van der Veken (1965) and Raynal (1973), but
was later correctly interpreted by Goetghebeur (1986,
1998). As in several other lineages, such as Ascolepis,
Lipocarpha and Alinula, Volkiella shows highly
derived pseudospikelets with a Bauplan comparable
with that of Lipocarpha, possessing a spikelet bract,
a spikelet prophyll, a proximal glume subtending the
single flower and a spikelet bract larger than the
glume. Peculiarly, in Volkiella, the spikelets are distichously arranged on the spike axis, whereas this
position is spiral in all other C4 Cyperus spp.
Although Volkiella shows an abundance of autapomorphic, derived characters which isolate it from all
other C4 Cyperus spp., it is nested in Lipocarpha
and should thus be sunk into Cyperus together with
Lipocarpha.
BASIS
FOR A MODERN CLASSIFICATION OF
CYPERUS
From the current and previous molecular phylogenetic analyses, it is evident that the classification
of Goetghebeur (1998) in Cypereae can no longer
be upheld without accepting paraphyletic genera.
Although most of the segregate genera are morphologically well circumscribed, the rapid diversification
of the Cyperus clade has resulted in several nested
paraphyletic entities (e.g. the genus Volkiella is
nested in the genus Lipocarpha, which is nested in
the group of C4 Cyperus spp. formerly known as
Mariscus, and C4 Cyperus is, in turn, nested in C3
Cyperus). Moreover, most morphological characteristics used for the delimitation of the different genera
related to Cyperus appear to have a high level of
homoplasy in the Cyperus clade (e.g. spiral glumes,
dorsiventrally flattened dimerous pistils, deciduous
spikelets, pseudospikelets; Fig. 2). Subsequently, different combinations of the same sets of these morphological characters have been used to circumscribe
most taxa.
Larridon et al. (2011a, b) placed the C3 segregate
genera in C3 Cyperus based on a well-resolved phylogenetic hypothesis combined with morphological,
embryographical, ontogenetic and anatomical data.
In that study, a classification for the Cyperus clade
was suggested in which two subgenera were recognized. Although Cyperus subgenus Anosporum (Nees)
C.B.Clarke (C3 Cyperus) is currently circumscribed as
a paraphyletic entity (Larridon et al., 2011a, b), the
single origin of the C4 photosynthetic pathway, a
clear apomorphy for the C4 Cyperus clade, forms a
sufficiently strong argument for the use of an evolutionary approach restricted to the subgeneric level in
Cyperus. For the lower level classification, a cladistic
approach was followed in circumscribing only monophyletic sections and, subsequently, the segregate
genera will be included in existing or new sections in
Cyperus.
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126
C4 CYPERUS PHYLOGENY (CYPERACEAE)
This classification can be extended to include the
different taxa of the C4 Cyperus clade (Cyperus subgenus Cyperus). However, as most segregate genera
are nested in a hard polytomy with many species from
different sections of Cyperus s.s. and as the lower
level relationships in several segregate genera are
poorly resolved, it is currently premature to build a
new sectional classification for the largest part of
Cyperus subgenus Cyperus. A joint international
effort will be necessary to expand the current phylogenetic studies with more DNA markers and taxa.
This will then serve as a basis for the growing modern
classification of the giant genus Cyperus.
CONCLUSIONS
From the data presented here, we conclude that the
Cyperus clade consists of a paraphyletic C3 Cyperus
and a well-supported monophyletic C4 Cyperus clade.
Nine segregate genera are nested in C4 Cyperus, i.e.
Alinula, Ascolepis, Lipocarpha, Kyllinga, Pycreus,
Queenslandiella, Remirea, Sphaerocyperus and Volkiella, most of which are monophyletic. Because they
are nested in the Cyperus clade, and as a consequence
of the multiple origins of the characters used to circumscribe them, we suggest that all nine C4 Cyperus
segregate genera should be included in a more
broadly circumscribed Cyperus. This study establishes a phylogenetic framework for future studies of
the different C4 Cyperus sections and segregates, and
for the taxonomic inclusion of the C4 segregate genera
into Cyperus s.l.
ACKNOWLEDGEMENTS
We thank Pieter Asselman (Ghent University) for his
helpful suggestions with the laboratory work and Andy
Vierstraete (Ghent University) for performing the
sequence reactions. We thank the Department of Environment and Natural Resources (DENR Region 8) for
providing a collecting permit for Cyperaceae in the
Philippines. We are grateful for the invitation of the
East African Herbarium (National Museums of Kenya,
Nairobi) and the Kenya Wildlife Service for the permission access to collect sedges in protected areas in
Kenya and their help in organizing the expedition. The
ANGAP Madagascar National Parks authority, the
general secretariat of the AETFAT congress 2010 and
the staff of the MBG office in Antananarivo are
acknowledged for their help in securing collecting
permits (N°082/10/MEF/SG/DGF/DCB.SAP/SLRSE –
Isabel Larridon) for Cyperaceae in Madagascar and for
their help in organizing the expedition. This work was
supported by research grants of the Special Research
Fund (BO5622, BO7418, BOF, Ghent University,
Belgium) and the Department of Biology, Ghent Uni-
123
versity, Belgium. The field expeditions were financed
by travel grants of the Research Foundation – Flanders (FWO) and the Leopold III-Fund and with support
of the Department of Biology, Ghent University,
Belgium. The phylogenetic analyses were carried out
using the Stevin Supercomputer Infrastructure at the
ICT Department of Ghent University, funded by Ghent
University, the Hercules Foundation and the Flemish
Government – Department EWI.
REFERENCES
Baillon H. 1894. Cyperaceae. Histoire des plantes 12 (Cyperaceae). Paris: Hachette, 335–382.
Ballard F. 1932. The genus Mariscopsis. Kew Bulletin 1932:
457–458.
Ballard F. 1933. Queenslandiella hyalina (Vahl) Ballard.
Hooker’s Icones Plantarum ser. 5, tab. 3208.
Bentham G. 1883. Cyperaceae. In: Bentham G, Hooker J,
eds. Genera plantarum 3. London: Reeve, 1037–1073.
Berry PE, Hipp AL, Wurdack KJ, Van Ee B, Riina R.
2005. Molecular phylogenetics of the giant genus Croton
and tribe Crotoneae (Euphorbiaceae sensu stricto) using ITS
and trnL-trnF DNA sequence data. American Journal of
Botany 92: 1520–1534.
Besnard G, Muasya AM, Russier F, Roalson EH,
Salamin N, Christin P-A. 2009. Phylogenomics of C4 photosynthesis in sedges (Cyperaceae): multiple appearances
and genetic convergence. Molecular Biology and Evolution
26: 1909–1919.
Blaser HW. 1941a. Studies in the morphology of the Cyperaceae 1. Morphology of the flowers A. Scirpoid genera.
American Journal of Botany 28: 542–551.
Blaser HW. 1941b. Studies in the morphology of the Cyperaceae. 1. Morphology of flowers B. Rhynchosporoid genera.
American Journal of Botany 28: 832–838.
Bruhl JJ. 1991. Comparative development of some taxonomically critical floral/inflorescence features in Cyperaceae.
Australian Journal of Botany 39: 119–127.
Bruhl JJ. 1995. Sedge genera of the world: relationships and
a new classification of the Cyperaceae. Australian Systematic Botany 8: 125–305.
Bruhl JJ, Wilson KA. 2007. Towards a comprehensive
survey of C3 and C4 photosynthetic pathways in Cyperaceae.
In: Columbus JT, Friar EA, Porter JM, Prince LM, Simpson
MG, eds. Monocots III/Grasses IV. Aliso 23. Claremont, CA:
Rancho Santa Ana Botanic Garden, 99–148.
Brummitt RK. 1996. In defence of paraphyletic taxa. In: van
der Maesen LJG, van der Burgt XM, van Medenbach de
Rooy JM, eds. The biodiversity of African plants, Proceedings XIVth AETFAT Congress, 22–27 August 1994, Wageningen, the Netherlands. Dordrecht: Kluwer, 371–384.
Brummitt RK, Sosef MSM. 1998. Paraphyletic taxa are
inherent in Linnaean classification – a reply to Freudenstein. Taxon 47: 411–412.
Castresana J. 2000. Selection of conserved blocks from multiple alignments for their use in phylogenetic analysis.
Molecular Biology and Evolution 17: 540–552.
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126
124
I. LARRIDON ET AL.
Chermezon H. 1919, publ. 1920. Cyperus nouveaux de
Madagascar. Bulletin de la Société Botanique de France 66:
338–353.
Chermezon H. 1922. Révision des Cypéracées de Madagascar 2. Annales du Musée Colonial de Marseille 30: 1–62 [ser.
3, 10].
Clarke CB. 1901–02. Cyperaceae. In: Thiselton-Dyer WT, ed.
Flora of tropical Africa 8: London: Lovell Reeve & Co,
266–524.
Clarke CB. 1908. New genera and species of Cyperaceae.
Kew Bulletin of Miscellaneous Information, Additional
Series 8: 1–196.
Endress PK. 2011. Evolutionary diversification of the flowers
in angiosperms. American Journal of Botany 98: 370–396.
Fenzl E. 1836. Cyperaceae. In: Endlicher S, ed. Genera
plantarum 2. Wien: Beck, 109–119.
Goetghebeur P. 1977. Studies in Cyperaceae 1. Taxonomic
notes on Ascolepis and Marisculus, a new genus of the tribe
Cypereae. Bulletin du Jardin Botanique National de
Belgique 47: 435–447.
Goetghebeur P. 1980. Studies in Cyperaceae 2. Contribution
towards a revision of the mainly African genus Ascolepis
Nees ex Steudel. Adansonia ser. 2, 19: 269–305.
Goetghebeur P. 1986. Genera Cyperacearum. Een bijdrage
tot de kennis van de morfologie, systematiek en fylogenese
van de Cyperaceae-genera. DPhil Thesis, Ghent University,
Belgium.
Goetghebeur P. 1998. Cyperaceae. In: Kubitzki K, ed. The
families and genera of vascular plants 4. Flowering plants –
monocotyledons. Berlin: Springer-Verlag, 141–190.
Goetghebeur P, Van den Borre A. 1989. Studies in Cyperaceae: 8. A revision of Lipocarpha, including Hemicarpha
and Rikliella. Wageningen Agricultural University Papers
89: 1–87.
Goetghebeur P, Vorster P. 1988. Studies in Cyperaceae 7.
The genus Alinula J.Raynal: a reappraisal. Bulletin du
Jardin Botanique National de Belgique 58: 457–465.
Govaerts R, Simpson DA, Goetghebeur P, Wilson KL,
Egorova T, Bruhl J. 2007. World Checklist of Cyperaceae.
Sedges. Kew: Kew Publishing.
Govaerts R, Simpson DA, Goetghebeur P, Wilson KL,
Egorova T, Bruhl J. 2012. World Checklist of Cyperaceae.
The Board of Trustees of the Royal Botanic Gardens, Kew.
Published on the Internet; Available at: http://www.kew.org/
wcsp/monocots/ [accessed 1 March 2012].
Govindarajalu E. 1975. Studies in Cyperaceae 14. Endomorphic evidences for placing Cyperus hyalinus under the new
subgenus Queenslandiella. Reinwardtia 9: 187–195.
Haines RW, Lye KA. 1971. Studies in African Cyperaceae 4.
Lipocarpha R.Br., Hemicarpha Nees and Isolepis R.Br.
Botaniska Notiser 124: 473–482.
Haines RW, Lye KA. 1983. The sedges and rushes of East
Africa. Nairobi: East African National History Society.
Harrison N, Kidner CA. 2011. Next-generation sequencing
and systematics: what can a billion base pairs of DNA
sequence data do for you? Taxon 60: 1552–1566.
Hooper SS. 1983. Remirea or Mariscus? – New support for a
monotypic genus in Cyperaceae. Kew Bulletin 38: 479–480.
Huygh W, Larridon I, Reynders M, Muasya AM, Govaerts R, Simpson DA, Goetghebeur P. 2010. Nomenclature and typification of names of genera and subdivisions of
genera in Cypereae (Cyperaceae): 1. Names of genera in the
Cyperus clade. Taxon 59: 1883–1890.
Kern JH. 1958. Florae Malesianae precursores 21. Notes on
Malayan and some SE Asian Cyperaceae 7. Acta Botanica
Neerlandica 7: 786–800.
Kern JH. 1974. Cyperaceae. In: van Steenis CGGJ, ed. Flora
Malesiana, ser. 1. Den Haag: Junk, 107–187.
Koyama T. 1976. Nomenclatural remarks on some Cyperaceae from southeastern Asia. Journal of Japanese Botany
51: 316–317.
Kükenthal G. 1935–36. Cyperaceae – Scirpoideae – Cypereae. In: Engler A, ed. Das Pflanzenreich 4 (20) [Heft 101].
Berlin: Engelmann, 1–671.
Kükenthal G. 1944. Vorarbeiten zu einer Monographie der
Rhynchosporoideae 14. Feddes Repertorium Specierum
Novarum Regni Vegetabilis 53: 187–219.
Kunth CS. 1837. Enumeratio plantarum 2. Cyperographia synoptica. Stuttgart & Tübingen: Sumtibus J.G.
Cottae.
Larridon I, Huygh W, Reynders M, Muasya AM, Govaerts R, Simpson DA, Goetghebeur P. 2011c. Nomenclature and typification of names of genera and subdivisions
of genera in Cypereae (Cyperaceae): 2. Names of subdivisions of Cyperus. Taxon 60: 868–884.
Larridon I, Reynders M, Huygh W, Bauters K, Van de
Putte K, Muasya AM, Boeckx P, Simpson DA, Vrijdaghs A, Goetghebeur P. 2011a. Affinities in C3 Cyperus
lineages (Cyperaceae) revealed using molecular phylogenetic data and carbon isotope analysis. Botanical Journal of
the Linnean Society 167: 19–46.
Larridon I, Reynders M, Huygh W, Bauters K, Vrijdaghs
A, Leroux O, Muasya AM, Goetghebeur P. 2011b. Taxonomic changes in C3 Cyperus (Cyperaceae) supported by
molecular phylogenetic data, morphology, embryography,
ontogeny and anatomy. Plant Ecology and Evolution 144:
327–356.
Li M-R, Wedin DA, Tieszen LL. 1999. C3 and C4
photosynthesis in Cyperus (Cyperaceae) in temperate
eastern North America. Canadian Journal of Botany 77:
18–209.
Lye KA. 1972. Studies in African Cyperaceae. 6. New species
and combinations in Kyllinga. Botaniska Notiser 125: 217–
219.
Lye KA. 1982. Studies in African Cyperaceae 21. New taxa
and combinations in Kyllinga Rottb. Nordic Journal of
Botany 1: 741–747.
Lye KA. 1983. Studies in African Cyperaceae 25. New taxa
and combinations in Cyperus L. Nordic Journal of Botany 3:
213–232.
Lye KA. 1997. Cyperaceae. In: Edwards S, Demissew S,
Hedberg I, eds. Flora of Ethiopia and Eritrea 6. Addis
Ababa: Addis Ababa University, 391–511.
Maslin BR, Miller JT, Seigler DS. 2003. Overview of the
generic status of Acacia (Leguminosae : Mimosoideae). Australian Systematic Botany 16: 1–18.
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126
C4 CYPERUS PHYLOGENY (CYPERACEAE)
Merxmüller H, Czech G. 1953. Eine neue Gattung der
Cyperaceae. Mitteilungen aus der Botanischen Staatssammlung München I (8): 317–323.
Miller JT, Bayer RJ. 2001. Molecular phylogenetics of
Acacia (Fabaceae: Mimosoideae) based on the chloroplast
matK coding sequence and flanking trnK intron spacer
regions. American Journal of Botany 88: 697–705.
Moore G, Smith GF, Figueiredo E, Demissew S, Lewis G,
Schrire B, Rico L, van Wyk AE. 2010. Acacia, the 2011
Nomenclature Section in Melbourne, and beyond. Taxon 59:
1188–1195.
Moore G, Smith GF, Figueiredo E, Demissew S, Lewis G,
Schrire B, Rico L, van Wyk AE, Luckow M, Kiesling R,
Sousa M. 2011. The Acacia controversy resulting from
minority rule at the Vienna Nomenclature Section: much
more than arcane arguments and complex technicalities.
Taxon 60: 852–857.
Muasya AM, Reynders M, Goetghebeur P, Simpson DA,
Vrijdaghs A. 2012. Dracoscirpoides (Cyperaceae) – a new
genus from Southern Africa, its taxonomy and floral ontogeny. South African Journal of Botany 72: 104–115.
Muasya AM, Simpson DA, Chase MW. 2002. Phylogenetic
relationships in Cyperus s.l. (Cyperaceae) inferred from
plastid DNA sequence data. Botanical Journal of the
Linnean Society 138: 145–153.
Muasya AM, Simpson DA, Chase MW, Culham A. 2001a.
A phylogeny of Isolepis (Cyperaceae) inferred using plastid
rbcL and trnL-F sequence data. Systematic Botany 26: 342–
353.
Muasya AM, Simpson DA, Chase MW. 2001b. Generic
relationships and character evolution in Cyperus s.l. Systematics and Geography of Plants 71: 539–544.
Muasya AM, Simpson DA, Verboom GA, Goetghebeur P,
Naczi RFC, Chase MW, Smets E. 2009a. Phylogeny of
Cyperaceae based on DNA sequence data: current progress
and future prospects. Botanical Review 75: 2–21.
Muasya AM, Viljoen J-A, Dludlu MN, Demissew S. In
press. Phylogenetic position of Cyperus clandestinus
(Cypereae, Cyperaceae) clarified by morphological and
molecular evidence. Nordic Journal of Botany.
Muasya AM, Vrijdaghs A, Simpson DA, Chase MW, Goetghebeur P, Smets E. 2009b. What is a genus in Cypereae:
phylogeny, character homology assessment and generic circumscription in Cypereae. Botanical Review 75: 52–66.
Nees von Esenbeck CG. 1834. Cyperaceae. In: G.A. WalkerArnott GA, ed. New genera of plants. Edinburgh New Philosophical Journal 17: 260–267.
Nees von Esenbeck CG. 1842. Florae Brasiliensis Cyperographia. In: von Martius CFP, ed. Flora Brasiliensis 2.
Munich & Leipzig: R. Oldenbourg, 1–226.
Nelson G, Murphy DJ, Ladiges PY. 2003. Brummitt on
paraphyly: a response. Taxon 52: 295–298.
Nylander JAA. 2004. MrModeltest v2. Program distributed
by the author. Uppsala University: Evolutionary Biology
Centre.
Oteng-Yeboah AA. 1975. Morphology, anatomy and taxonomy of the genus Remirea Aublet (Cyperaceae). Boissiera
24 A: 197–205.
125
Pax F. 1888. Cyperaceae. In: Engler A, Prantl K, eds. Die
natürlichen Pflanzen-familien. 1, 2 (2). Leipzig: Engelmann,
98–126.
Rambaut A, Drummond AJ. 2007. Tracer v1.4. Available
from http://beast.bio.ed.ac.uk/Tracer (accessed 1 March
2010).
Raynal J. 1973. Notes cypérologiques 19. Contribution à la
classification de la sous-famille des Cyperoideae. Adansonia
sér. 2, 13: 145–171.
Raynal J. 1977. Notes cypérologiques 31. Mélanges nomenclaturaux (Cyperoideae). Adansonia sér. 2, 17: 43–47.
Reynders M, Goetghebeur P. 2010. Reestablishment of
Pycreus section Tuberculati (Cyperaceae). Blumea 55: 226–
230.
Reynders M, Huygh W, Larridon I, Muasya AM, Govaerts R, Simpson DA, Goetghebeur P. 2011. Nomenclature and typification of names of genera and subdivisions of
genera in the Cypereae (Cyperaceae): 3. Names in segregate
genera of Cyperus. Taxon 60: 885–895.
Reynders M, Vrijdaghs A, Muasya AM, Larridon I, Goetghebeur P, Smets E. 2012. Evolution of the gynoecium in
Cyperoideae (Cyperaceae): congenital fusion of carpels
facilitates pistil modifications. Combining evidence from
floral ontogeny and anatomy. Plant Ecology and Evolution
145: 96–125.
Ridley HN. 1884. The Cyperaceae of the West Coast of Africa
in the Welwitsch herbarium. Transactions of the Linnean
Society of London. Botany 20: 329–338.
Ronquist F, Huelsenbeck JP. 2003. MRBAYES 3: bayesian
phylogenetic inference under mixed models. Bioinformatics
19: 1572–1574.
Simpson DA, Furness CA, Hodkinson TR, Muasya AM,
Chase MW. 2003. Phylogenetic relationships in Cyperaceae
subfamily Mapanioideae inferred from pollen and plastid
DNA sequence data. American Journal of Botany 90: 1071–
1086.
Simpson DA, Muasya AM, Alves M, Bruhl JJ,
Dhooge S, Chase MW, Furness CA Ghamkhar K, Goetghebeur P, Hodkinson TR, Marchant AD, Nieuborg R,
Reznicek AA, Roalson EH, Smets E, Starr JR,
Thomas WW, Wilson KL, Zhang X. 2007. Phylogeny
of Cyperaceae based on DNA sequence data – a new
rbcL analysis. In: Columbus JT, Friar EA, Porter JM,
Prince LM, Simpson MG, eds. Monocots III/Grasses IV.
Aliso 23. Claremont, CA: Rancho Santa Ana Botanic
Garden, 72–83.
Smith GF, Figueiredo E. 2011. Conserving Acacia Mill.
with a conserved type: what happened in Melbourne? Taxon
60: 1504–1506.
Stamatakis A. 2006. RAxML-VI-HPC: maximum likelihoodbased phylogenetic analyses with thousands of taxa and
mixed models. Bioinformatics 22: 2688–2690.
Stamatakis A, Hoover P, Rougemont J. 2008. A rapid
bootstrap algorithm for the RAxML Web Servers. Systematic Biology 57: 758–771.
Starr JR, Ford BA. 2009. Phylogeny and evolution in Cariceae (Cyperaceae): current knowledge and future directions. Botanical Review 75: 110–137.
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126
126
I. LARRIDON ET AL.
Steinmann VW, Porter JM. 2002. Phylogenetic relationships in Euphorbieae (Euphorbiaceae) based on ITS and
ndhF sequence data. Annals of the Missouri Botanical
Garden 89: 453–490.
von Steudel EG. 1854–55. Synopsis plantarum glumacearum 2. Cyperaceae. Stuttgart: J.B. Metzler.
Stock WD, Chuba DK, Verboom GA. 2004. Distribution of
South African C3 and C4 species of Cyperaceae in relation
to climate and phylogeny. Austral Ecology 29: 313–319.
Thiele KR, Funk VA, Iwatsuki K, Morat P, Peng CI,
Raven PH, Sarukhan J, Seberg O. 2011. The controversy
over the retypification of Acacia Mill. with an Australian
type: a pragmatic view. Taxon 60: 194–198.
Tucker GC. 1983. The taxonomy of Cyperus (Cyperaceae) in
Costa Rica and Panama. Systematic Botany Monographs 2:
85.
Van der Veken P. 1965. Contribution à l’embryographie
systématique 1 des Cyperaceae-Cyperoideae. Bulletin du
Jardin botanique de l’État à Bruxelles 35: 285–354.
Vrijdaghs A. 2006. A floral ontogenetic approach to homology
questions in non-mapanioid Cyperaceae. DPhil Thesis, K.U.
Leuven, Leuven, Belgium.
Vrijdaghs A, Goetghebeur P, Smets E, Muasya AM. 2006.
The floral scales in Hellmuthia (Cyperaceae, Cyperoideae)
and Paramapania (Cyperaceae, Mapanioideae): an ontogenetic study. Annals of Botany 98: 619–630.
Vrijdaghs A, Muasya AM, Goetghebeur P, Caris P,
Nagels A, Smets E. 2009. A floral ontogenetic approach to
questions of homology within the Cyperoideae (Cyperaceae).
Botanical Review 75: 30–51.
Vrijdaghs A, Reynders M, Larridon I, Muasya AM,
Smets E, Goetghebeur P. 2010. Spikelet structure and
development in Cyperoideae (Cyperaceae): a monopodial
general model based on ontogenetic evidence. Annals of
Botany 105: 555–571.
Vrijdaghs A, Reynders M, Muasya AM, Larridon I, Goetghebeur P, Smets E. 2011. Spikelet and floral morphology
and development in Cyperus and Pycreus (Cyperaceae).
Plant Ecology and Evolution 144: 44–63.
Walker JB, Sytsma KJ, Reutlein J, Wink M. 2004. Salvia
(Lamiaceae) is not monophyletic: implications for the systematics, radiation, and ecological specializations of Salvia
and tribe Mentheae. American Journal of Botany 91: 1115–
1125.
Yano O, Ikeda H, Watson MF, Rajbhandari KR, Jin X-F,
Hoshino T, Muasya AM, Ohba H. 2012. Phylogenetic
position of the Himalayan genus Erioscirpus (Cyperaceae)
inferred from DNA sequence data. Botanical Journal of the
Linnean Society 170: 1–11.
© 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 106–126