ArticlePDF Available

Resolving basal lamiid phylogeny and the circumscription of Icacinaceae with a plastome-scale data set

Authors:

Abstract and Figures

Premise of the study: Major relationships within Lamiidae, an asterid clade with ∼40000 species, have largely eluded resolution despite two decades of intensive study. The phylogenetic positions of Icacinaceae and other early-diverging lamiid clades (Garryales, Metteniusaceae, and Oncothecaceae) have been particularly problematic, hindering classification and impeding our understanding of early lamiid (and euasterid) character evolution. Methods: To resolve basal lamiid phylogeny, we sequenced 50 plastid genomes using the Illumina sequencing platform and combined these with available asterid plastome sequence data for more comprehensive phylogenetic analyses. Key results: Our analyses resolved basal lamiid relationships with strong support, including the circumscription and phylogenetic position of the enigmatic Icacinaceae. This greatly improved basal lamiid phylogeny offers insight into character evolution and facilitates an updated classification for this clade, which we present here, including phylogenetic definitions for 10 new or converted clade names. We also offer recommendations for applying this classification to the Angiosperm Phylogeny Group (APG) system, including the recognition of a reduced Icacinaceae, an expanded Metteniusaceae, and two orders new to APG: Icacinales (Icacinaceae + Oncothecaceae) and Metteniusales (Metteniusaceae). Conclusions: The lamiids possibly radiated from an ancestry of tropical trees with inconspicuous flowers and large, drupaceous fruits, given that these morphological characters are distributed across a grade of lineages (Icacinaceae, Oncothecaceae, Metteniusaceae) subtending the core lamiid clade (Boraginales, Gentianales, Lamiales, Solanales, Vahlia). Furthermore, the presence of similar morphological features among members of Aquifoliales suggests these characters might be ancestral for the Gentianidae (euasterids) as a whole.
Content may be subject to copyright.
A ME RI CA N JO UR NA L OF B OTA NY 102 ( 11 ): 1 20 , 2015 ; http://www.amjbot.org/ © 2015 Botanical Society of America 1
AMERICAN JOURNAL OF BOTANY
RESEARCH ARTICLE
Lamiidae are a major clade of asterid angiosperms, including
~40 000 species, or ~15% of angiosperm species richness ( Refulio-
Rodriguez and Olmstead, 2014 ). Earlier studies have referred to this
clade informally as asterids I ( Chase et al., 1993 ), euasterids I ( APG,
1998 ; Soltis et al., 1999a ; APG II, 2003 ), or lamiids ( Bremer et al.,
2002 ; Judd and Olmstead, 2004 ; APG III, 2009 ). Although Cantino
et al. (2007) applied the name Garryidae to this clade, it has more
commonly been called Lamiidae ( R e f u l i o - R o d r i g u e z a n d O l m stead,
2014 ), and this treatment will be followed in the Companion Vol-
ume of the PhyloCode (R. G. Olmstead, University of Washington,
personal communication; note that all clade names are in italics
following Cantino et al., 2007 ).
Lamiids are generally characterized by superior ovaries and co-
rollas with late sympetaly ( Erbar and Leins, 1996 ; Judd et al., 2008 ),
but considerable variation in morphology occurs across the clade,
and nonmolecular synapomorphies are unclear ( Stevens, 2001
onward ; Judd and Olmstead, 2004 ). Phylogenetic studies over the past
20 years (e.g., Olmstead et al., 1992 , 1993 , 2000 ; Chase et al., 1993 ;
Soltis et al., 1999a , 2000 , 2011 ; Savolainen, 2000a , b ; Albach et al.,
2001 ; Bremer et al., 2002 ; Refulio-Rodriguez and Olmstead, 2014 )
have clarified the composition of Lamiidae . H o w e v e r , r e l a t i o n -
ships among the major lineages have largely eluded resolution.
Most lamiid diversity falls into a clade informally known as the
core lamiids” ( Refulio-Rodriguez and Olmstead, 2014 ; the formal
1 Manuscript received 23 June 2015; revision accepted 16 September 2015.
2 Department of Biology, University of Florida, Gainesville, Florida 32611-8525 USA;
3 Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611-7800
USA; and
4 Herbario CICY, Centro de Investigación Cientí cas de Yucatán A. C., Mérida, Yucatán
97200 Mexico
5 Author for correspondence (e-mail: gwstull@gmail.com)
doi:10.3732/ajb.1500298
Resolving basal lamiid phylogeny and the
circumscription of Icacinaceae with a plastome-scale
data set
1
Gregory W. Stull
2,3,5 , Rodrigo Duno de Stefano
4 , Douglas E. Soltis
2,3 , and Pamela S. Soltis
3
PREMISE OF THE STUDY: Major relationships within Lamiidae , an asterid clade with ~40 000 species, have largely eluded resolution despite two decades of
intensive study. The phylogenetic positions of Icacinaceae and other early-diverging lamiid clades (Garryales, Metteniusaceae, and Oncothecaceae) have
been particularly problematic, hindering classi cation and impeding our understanding of early lamiid (and euasterid) character evolution.
METHODS: To resolve basal lamiid phylogeny, we sequenced 50 plastid genomes using the Illumina sequencing platform and combined these with avail-
able asterid plastome sequence data for more comprehensive phylogenetic analyses.
KEY RESULTS: Our analyses resolved basal lamiid relationships with strong support, including the circumscription and phylogenetic position of the enig-
matic Icacinaceae. This greatly improved basal lamiid phylogeny o ers insight into character evolution and facilitates an updated classi cation for this
clade, which we present here, including phylogenetic de nitions for 10 new or converted clade names. We also o er recommendations for applying this
classi cation to the Angiosperm Phylogeny Group (APG) system, including the recognition of a reduced Icacinaceae, an expanded Metteniusaceae, and
two orders new to APG: Icacinales (Icacinaceae + Oncothecaceae) and Metteniusales (Metteniusaceae).
CONCLUSIONS: The lamiids possibly radiated from an ancestry of tropical trees with inconspicuous owers and large, drupaceous fruits, given that these
morphological characters are distributed across a grade of lineages (Icacinaceae, Oncothecaceae, Metteniusaceae) subtending the core lamiid clade (Bor-
aginales, Gentianales, Lamiales, Solanales, Vahlia ). Furthermore, the presence of similar morphological features among members of Aquifoliales suggests
these characters might be ancestral for the Gentianidae (euasterids) as a whole.
K E Y W O R D S Garryales; Icacinaceae; Lamiidae ; Metteniusaceae; Oncothecaceae; phylogenetic nomenclature; phylogenomics; plastid genome
http://www.amjbot.org/cgi/doi/10.3732/ajb.1500298The latest version is at
AJB Advance Article published on October 29, 2015, as 10.3732/ajb.1500298.
Copyright 2015 by the Botanical Society of America
2 A M E R I C A N J O U R N A L O F B O T A N Y
name Lamianae will be applied to this clade in the upcoming
Companion Volume to the PhyloCode, R. G. Olmstead, Univer-
sity of Washington, personal communication), which includes
four species-rich groups—Boraginales, Gentianales, Lamiales, and
Solanales—as well as the small, phylogenetically isolated genus
Vahli a T h u n b . R e l a t i o n s h i p s a m o n g t h e s e f i v e g r o u p s h a v e v a r -
ied across studies and rarely received strong bootstrap support
( Olmstead et al., 1992 , 1993 , 2000 ; Soltis et al., 1999a , 2000 , 2011 ;
Savolainen, 2000a , b ; Albach et al., 2001 ; Bremer et al., 2002 ),
although a recent study by Refulio-Rodriguez and Olmstead (2014)
found moderate support for (Gentianales, ((Solanales + Vahliaceae),
(Boraginales + Lamiales))).
Subtending the core lamiids are multiple phylogenetically iso-
lated lineages of uncertain placement, which we informally call the
“basal lamiids” because they possibly comprise a grade at the base
of the lamiid tree. ese include Garryales (Eucommiaceae and
Garryaceae), Icacinaceae, and the monogeneric families Metteniusa-
ceae and Oncothecaceae. Relationships among the basal lamiids are
poorly known largely because previous studies (e.g., Kårehed, 2001 ;
González et al., 2007 ; Lens et al., 2008 ; Soltis et al., 2011 ; Byng et al.,
2014 ; Refulio-Rodriguez and Olmstead, 2014 ) have included an in-
su cient sampling of characters and/or taxa to investigate this
phylogenetic problem comprehensively.
e Icacinaceae, with ~34 genera and 200 species ( Kårehed,
2001 ; Byng et al., 2014 ), constitute the most diverse basal lamiid
family. ey are of particular importance for understanding basal
lamiid phylogeny because the family, as currently recognized
( Kårehed, 2001 ), is likely not monophyletic, with some members
considered probably more closely related to other basal lamiid
groups ( Lens et al., 2008 ; Byng et al., 2014 ). e traditional circum-
scription of the family (referred to henceforth as Icacinaceae s.l.)
has included ~54 genera and 400 species, united largely by the pres-
ence of superior, unilocular ovaries with two pendant ovules, only
one of which matures ( Engler, 1893 ; Howard, 1940 ; Sleumer, 1942 ,
1969 , 1971 ; Kårehed, 2001 ). e family was previously considered a
rosid group and was placed with Celastraceae and Aquifoliaceae
( Miers, 1852 , 1864 ), although earlier authors ( de Candolle, 1824 ;
Bentham, 1841 , 1862 ) had associated members of Icacinaceae s.l.
with Olacaceae of Santalales (a superasterid; Soltis et al., 2011 ).
e most widely adopted infrafamilial classi cation of Icacina-
ceae s.l. was that of Engler (1893) and Sleumer (1942) , who divided
the family into four tribes—Icacineae (including >30 genera), Io-
deae ( Hosiea Hemsley & E. H. Wilson, Iodes Blume, Mappianthus
Hand.-Mazz., Natsiatopsis Kurz, Natsiatum Buch.-Ham. ex Arn.,
and Polyporandra Becc.), Sarcostigmateae ( Sarcostigma Wight &
Arn.), and Phytocreneae ( Chlamydocarya Baill., Miquelia Meisn,
Phytocrene Wall., Polycephalium Engl., Pyrenacantha Wight, and
Stachyanthus Engl.)—based largely on wood anatomical charac-
ters. However, various lines of morphological evidence—e.g.,
pollen ( Dahl, 1952 ; Lobreau-Callen, 1972 , 1973 ), leaf epidermal
characters ( van Staveren and Baas, 1973 ), nodal anatomy ( Bailey
and Howard, 1941a ), and wood anatomy ( Bailey and Howard,
1941b d )—suggested that the aforementioned tribes, and espe-
cially Icacineae, might not be monophyletic. Bailey and Howard
(1941b) instead organized the family into three informal groups
based on vessel characters of the primary and secondary xylem and
nodal anatomy (i.e., the presence of uni- vs. trilacunar nodes).
Group I included ~13 genera from the Icacineae characterized by
trilacunar nodes and vessels of both the primary and secondary xy-
lem with scalariform performations. Group II included ~10 genera
from the Icacineae characterized by trilacunar nodes and vessels of
the secondary xylem with scalariform-porous perforations. Group
III included ~23 genera, representing all four tribes, characterized
by unilacunar nodes and vessels of the secondary xylem with sim-
ple perforations ( Bailey and Howard, 1941a , b ).
Multiple phylogenetic studies have shown Icacinaceae s.l. to be
highly polyphyletic ( Soltis et al., 1999a , 2000 ; Savolainen et al.,
2000b ; Kårehed, 2001 ), with members falling near the base of either
the lamiids or the campanulids (=euasterids II). Kårehed (2001)
conducted the rst family-wide phylogenetic investigation of Icaci-
naceae, based primarily on ndhF sequences—although a sparse
sampling of several other loci ( rbcL , atpB , and 18S rDNA) was also
included—and ~70 morphological characters across 45 of the ~54
traditional genera. As a result, Kårehed (2001) transferred ~18 gen-
era to the campanulid families Cardiopteridaceae (Aquifoliales),
Pennantiaceae (Apiales), and Stemonuraceae (Aquifoliales). e
remaining 34 genera (only 16 of which were sampled for molecular
characters) were provisionally retained in Icacinaceae by Kårehed
(2001) , although it was evident that these genera might not consti-
tute a monophyletic group. e 34 genera appeared to comprise
four clades—which Kårehed (2001) informally called the Apodytes,
Cassinopsis , Emmotum , and Icacina groups—but the relationships
among these groups and the other basal lamiid lineages were
unclear.
More recent studies of Icacinaceae have included greater sam-
pling of morphological/anatomical characters ( Lens et al., 2008 ) or
additional genera not included in previous studies ( Angulo et al.,
2013 ; Byng et al., 2014 ). However, these studies were still unable to
clarify the circumscription of the family and relationships among
basal lamiids. Nevertheless, Byng et al. (2014) con rmed the place-
ment of Dendrobangia Rusby among the basal lamiids—as opposed
to in Cardiopteridaceae (Aquifoliales), where it had been placed
previously ( Kårehed, 2001 )—and resolved some relationships
within the Icacina group.
Resolving lamiid relationships, particularly toward the base of
the tree, is critical for establishing an improved classi cation sys-
tem for this clade. It is also essential for interpreting patterns of
character evolution across not only the lamiids but also the whole
of the core asterids (
Stevens, 2001 onward ; Endress and Rapini,
2014 ), i.e., the clade comprising the lamiids + campanulids (~80 000
species). e core asterids have been referred to informally as
euasterids (e.g., APG I, 1998 ) and formally as the Gentianidae
( Cantino et al., 2007 ); we will use this latter name throughout the
paper. In many respects, the basal lamiids di er morphologically
from the core lamiid clade. For example, the core lamiids are vari-
able in habitat and habit and characterized by showy, sympetalous
owers with epipetalous stamens and distinctly two-carpellate/
loculate gynoecia; the fruits are variable but usually contain multi-
ple relatively small seeds ( Stevens, 2001 onward ; Judd et al., 2008 ).
In contrast, the basal lamiids are strictly woody (trees, shrubs, or
lianas) and generally occur in tropical rainforest ( Sleumer, 1971 ;
Carpenter and Dickison, 1976 ; González et al., 2007 ; Hua and
Howard, 2008 ). e owers are small, with petal apices o en in-
exed in bud, varying degrees of perianth connation, and unilocu-
lar gynoecia ( Sleumer, 1942 ; Howard, 1942b , d ; González and
Rudall, 2010 ). e fruits are large and eshy, generally drupaceous,
usually containing one large seed ( Sleumer, 1942 ; Howard, 1942b ,
d ; González and Rudall, 2010 ). If the basal lamiids do indeed form
a grade leading to the core clade, this topology would parsimoni-
ously suggest that the aforementioned characters are ancestral for
N O V E M B E R 2015 , VOLUME 102 STULL ET AL. RESOLVING BASAL LAMIID PHYLOGENY 3
the lamiids. Furthermore, many of these characters are also shared
by members of Aquifoliales ( Howard, 1942c , d , 1943a c ; Stevens,
2001 onward ), which are sister to the rest of the campanulids ( Soltis
et al., 2011 ), suggesting that these morphological features might
represent ancestral states for Gentianidae as a whole (see also Endress
and Rapini, 2014 ).
To resolve basal lamiid phylogeny, we sequenced 50 plastid ge-
nomes across the core asterids, focusing on the basal lamiid genera,
and combined these with publically available asterid plastome data
for comprehensive phylogenetic analyses. e resulting data matrix
comprised 112 accessions, including all families and 36 of the 38
currently recognized genera of basal lamiids. On the basis of our
results, we present a phylogenetic classi cation for Icacinaceae and
the basal lamiids, providing formal de nitions for 10 clade names
following the PhyloCode version 4c ( Cantino and de Queiroz,
2010 ; http://www.ohio.edu/phylocode/toc.htm l). is treatment
includes the conversion of six names already recognized under the
International Code of Nomenclature for Algae, Fungi, and Plants
(ICN; McNeill et al., 2012 ) (e.g., Icacinaceae Miers) and four new
clade names. We also o er suggestions for the application of these
clade names under a rank-based system (namely, the Angiosperm
Phylogeny Group). Finally, we discuss the general implications of
our results for understanding patterns of character evolution across
Gentianidae .
MATERIALS AND METHODS
Taxon sampling We included 112 accessions (=109 species)
across Asteridae with a sampling emphasis on the basal lamiid lin-
eages (Appendix S1, see Supplemental Data with online version of
this article). Plastomes of 50 species were newly sequenced for this
study (with the majority being basal lamiids; one campanulid spe-
cies, Discophora guianensis Miers, was also sequenced). Voucher
information for the newly sequenced taxa is presented in Table 1 .
Data for the other species included were obtained from GenBank
or the 1KP Project ( http://onekp.com/ ).
e basal lamiids comprise 38 genera: Aucuba , Eucommia , Gar-
rya (Garryales), Metteniusa (Metteniusaceae), Oncotheca (Onco-
thecaceae), and the 33 genera of Icacinaceae sensu Kårehed (2001 :
see table 4). is generic tally for Icacinaceae accounts for the newly
described genus Sleumeria Utteridge, Nagam. & Teo ( Utteridge
et al., 2005 ), the synonymization of three genera ( Chlamydocarya
Baill. and Polycephalium Engl. = Pyrenacantha Wight; Polyporan-
dra Becc. = Iodes Blume; Byng et al., 2014 ), and the position of Den-
drobangia in/near the Apodytes group ( Byng et al., 2014 ). We
sampled 47 basal lamiid species, representing all currently recog-
nized families and 36/38 genera (with Sleumeria and Natsiatopsis
Kurz being the only two missing genera). In general, we sampled
only one species per genus, but in the cases of Iodes and Pyrenacan-
tha , multiple species were sampled to provide an initial assessment
of the monophyly of these diverse and widespread taxa.
W e s a m p l e d 5 1 r e p r e s e n t a t i v e s f r o m t h e c o r e l a m i i d s ( R e f u l i o -
Rodriguez and Olmstead, 2014 ), including multiple representatives
from each of the four recognized orders (Boraginales: 9 spp., Gentia-
nales: 16 spp., Lamiales: 13 spp., Solanales: 12 spp.), as well as a spe-
cies from the phylogenetically isolated genus Vahlia . For outgroups,
we included 10 representatives of the Campanulidae , a s w e l l a s Cor-
nus a n d Rhododendron , which represent the successive sister groups
(Cornales and Ericales) to the core asterids ( Soltis et al., 2011 ).
DNA isolation and sequencing We used a modi ed CTAB proto-
col ( Doyle and Doyle, 1987 ) to obtain genomic DNA from either
herbarium-sampled or silica-dried leaf tissue ( Table 1 ). To build
genomic libraries for next-generation sequencing, we followed the
procedure of Stull et al. (2013) , using insert sizes in the range of
200–400 bp. Following library construction, the samples were di-
vided among three separate sequencing runs. e rst two involved
no plastid enrichment. One of these included 12 samples (11 for
this project) multiplexed on one lane of the Illumina GAIIx (2 ×
100 bp; Interdisciplinary Center for Biotechnology Research, Uni-
versity of Florida). e other included 13 samples (8 for this proj-
ect) multiplexed on one lane of the Illumina MiSeq (2 × 150 bp;
Biotechnology Center, University of Wisconsin-Madison). e
third sequencing run involved enrichment of the plastid genome
using the probe set and method of Stull et al. (2013) before multi-
plex sequencing on one lane of the Illumina HiSeq (1 × 100 bp;
Biotechnology Center, University of Wisconsin-Madison). For this
run, 95 samples were multiplexed in total, but only 31 of these were
included for this study. Table 1 presents the number of reads ob-
tained from each sample, as well as other pertinent sequencing in-
formation. e raw reads generated from these sequencing runs
were submitted to the Sequence Read Archive (SRP063611).
Plastome assembly and alignment A er sequencing, the reads
were barcode-sorted and trimmed using the FASTX-Toolkit
( http://hannonlab.cshl.edu/fastx_toolkit/download.html ). e reads
were then quality ltered using the FASTX-Toolkit or Sickle ( Joshi
and Fass, 2011 ; https://github.com/najoshi/sickle ). We used two
di erent approaches to assemble the reads for subsequent phyloge-
netic analyses. In the rst, we conducted de novo assemblies using
Velvet 1.2 ( Zerbino and Birney, 2008 ), followed by reference-
guided assembly of the contigs using Geneious 6.0.4 ( www.
geneious.com ) to obtain complete to nearly complete plastomes. A
complete plastid genome of Aucuba japonica (M. J. Moore, Oberlin
College, unpublished data; individual genes, however, were ana-
lyzed and published by Moore et al. [2010] ) was used as the initial
reference for this approach. e resulting plastomes were then up-
loaded to DOGMA ( http://dogma.ccbb.utexas.edu/ ; Wyman et al.,
2004 ) to extract the protein-coding regions for phylogenetic analy-
sis. We also used these extracted regions as references for the
second assembly approach, employing the program Assembly by
Reduced Complexity ( http://ibest.github.io/ARC/ ; Hunter et al.,
2015 ), a hybrid mapping/de novo assembly method for targeted
loci. e gene sequences assembled under both approaches were
then sorted together by gene to create individual les for alignment
and subsequent phylogenetic analyses.
e nal data set included 73 protein-coding genes (Appendix
S1). We excluded the other six protein-coding plastid regions of the
plastome ( petG , psbZ , rps7 , rps12 , ycf1 , and ycf3 ) due to poor as-
sembly from our Illumina data and/or their absence from the 1KP
data set.
Multiple sequence alignment was performed on each of the 73
genes individually using MAFFT v.7.220 ( Katoh and Standley,
2013 ), followed by manual inspection in Geneious. Using Ge-
neious, we translated the alignments and made adjustments as
needed to ensure that each of the coding regions was in the correct
reading frame.
A er concatenation of the individual loci, the combined data set
had an aligned length of 59 113 bp, with 23.4% missing data across
all loci (Appendix S1). e aligned lengths of the individual loci are
4 A M E R I C A N J O U R N A L O F B O T A N Y
listed in online Appendix S2. irteen accessions had >50% miss-
ing data, and most of these accessions were core lamiids from the
1KP project; only four were basal lamiids. Nothapodytes montana
and Lavigera macrocarpa had 53% and 80% missing data, respec-
tively, due to poor assembly of the plastome from the Illumina
reads; Dendrobangia and Poraqueiba Aubl. each had 94.7% missing
data because we were unable to sequence these taxa for this study
and instead included them based on ve plastid loci from GenBank
( matK , psbA , rbcL , rpoB , and rpoC1 ). Appendix S1 shows the distri-
bution of missing data via a taxon-by-gene table. e data matrix
analyzed for this paper is available on TreeBASE ( http://purl.org/
phylo/treebase/phylows/study/TB2:S18118 ) and Dryad (doi:10.5061/
dryad.v7g2k). e individual gene sequences assembled and analyzed
for this study were submitted to GenBank (see online Appendix S3
TABLE 1. Species sequenced for this study, including voucher and sequencing information. In the “Voucher” column, the herbarium locations for each voucher
are noted in parentheses, using the herbarium codes from the Index Herbariorum ( http://sweetgum.nybg.org/ih/ ). The samples noted with an asterisk in the
“Sequencer: read info” column were plastid-enriched prior to sequencing.
Clade/family Taxon Voucher Tissue source Sequencer: read info No. reads obtained
Basal lamiids
Garryaceae Garrya avescens Heany 2158 (FLAS) Silica GAIIx: 2 × 100 5 721 128
Icacinaceae Alsodeiopsis poggei Stone et al., 3237 (MO) Silica GAIIx: 2 × 100 5 744 996
Casimirella guaranitica Zardini 43662 (MO) Silica HiSeq: 1 × 100* 690 688
Cassinopsis madagascariensis Lowry 5162 (MO) Herbarium MiSeq: 2 × 150 2 357 614
Desmostachys planchoniana Rabevohitra et al., 4419 (MO) Silica GAIIx: 2 × 100 7 454 176
Hosiea japonica Sugawara s.n. (MO: 4020073) Herbarium MiSeq: 2 × 150 1 967 318
Icacina mannii Leeuwenberg 2708 (UC) Herbarium GAIIx: 2 × 100 5 977 218
Iodes cirrhosa Nihn 11463 (L) Herbarium HiSeq: 1 × 100* 2 775 225
Iodes klaineana Wieringa 6280 (WAG) Silica HiSeq: 1 × 100* 2 441 786
Iodes liberica Jongkind 9410 (WAG) Herbarium HiSeq: 1 × 100* 2 705 201
Iodes perrieri Jongkind 3693 (MO) Herbarium MiSeq: 2 × 150 2 075 838
Iodes ( Polyporandra ) scandens Takeuchi 9320 (MO) Herbarium MiSeq: 2 × 150 1 822 700
Iodes seretii Wieringa 4427 (WAG) Herbarium HiSeq: 1 × 100* 2 321 195
Lavigeria macrocarpa Wieringa 5840 (WAG) Silica HiSeq: 1 × 100* 1 745 017
Leretia cordata Stull 125 (LPB) Silica HiSeq: 1 × 100* 2 647 287
Mappia mexicana Gonzalez-Medrano 7265 (MEXU) Herbarium MiSeq: 2 × 150 2 025 392
Mappianthus iodoides McClure 8569 (UC) Herbarium GAIIx: 2 × 100 4 907 828
Merrilliodendron megacarpum Moran 4718 (UC) Herbarium GAIIx: 2 × 100 6 456 008
Miquelia caudata Beaman 7504 (L) Herbarium HiSeq: 1 × 100* 3 621 133
Natsiatum herpeticum Chand 8312 (L) Herbarium HiSeq: 1 × 100* 1 152 495
Nothapodytes montana Beusekom 48 (L) Herbarium HiSeq: 1 × 100* 935 827
Phytocrene borneensis Ambri W885 (L) Herbarium HiSeq: 1 × 100* 2 035 139
Phytocrene racemosa Hotta 12687 (L) Herbarium HiSeq: 1 × 100* 2 287 487
Pleurisanthes ava Ho man 2806 (L) Herbarium HiSeq: 1 × 100* 1 349 029
Pyrenacantha acuminata Wieringa 5017 ( WAG) Silica HiSeq: 1 × 100* 2 710 015
Pyrenacantha gabonica Breteler 15281 (WAG) Herbarium HiSeq: 1 × 100* 1 454 094
Pyrenacantha ( Polycephalium ) lobata Wieringa 4409 (WAG) Herbarium HiSeq: 1 × 100* 2 420 522
Pyrenacantha malvifolia Wilde 7281 (MO) Herbarium HiSeq: 1 × 100* 4 208 917
Pyrenacantha rakotazafyi Barthelat 1764 (MO) Herbarium MiSeq: 2 × 150 2 052 890
Pyrenacantha ( Chlamydocarya )
thomsoniana
Wieringa 6295 (WAG) Silica HiSeq: 1 × 100* 7 977 710
Rhyticaryum macrocarpum Katik 46856 (L) Herbarium HiSeq: 1 × 100* 1 649 132
Sarcostigma paniculata Beaman 7056 (L) Herbarium HiSeq: 1 × 100* 984 900
Stachyanthus zenkeri Cheek 5009 (MO) Herbarium HiSeq: 1 × 100* 2 133 225
Metteniusaceae Apodytes dimidiata Rabevohitra et al., 4533 (MO) Silica GAIIx: 2 × 100 8 640 592
Calatola mollis Ambrosio 346 (MO) Herbarium HiSeq: 1 × 100* 1 113 992
Emmotum nitens Thomas et al., 12893 (CICY) Herbarium GAIIx: 2 × 100 3 981 300
Metteniusa tessmanniana Lewis et al., 3447 (MO) Herbarium HiSeq: 1 × 100* 1 054 884
Oecopetalum mexicanum Lascurain 360 (CICY) Herbarium GAIIx: 2 × 100 5 324 216
Ottoschulzia rhodoxylon Trego s.n. (CICY) Silica GAIIx: 2 × 100 4 116 382
Pittosporposis kerrii Stull 132 (FLAS) Silica MiSeq: 2 × 150 4 903 968
Platea parvi ora Averyanov et al. VH4429 (MO) Silica MiSeq: 2 × 150 1 734 998
Rhaphiostylis ferruginea Merello et al., 1645 (MO) Silica GAIIx: 2 × 100 5 809 890
Oncothecaceae Oncotheca balansae Carlquist 15610 (MO) Herbarium HiSeq: 1 × 100* 1 495 155
Core lamiids
Boraginaceae Borago o cinalis Davis 1516 (FLAS) Herbarium HiSeq: 1 × 100* 2 626 335
Boraginaceae Cordia sebastina Stull 128 (FLAS) Silica HiSeq: 1 × 100* 1 338 956
Hydroleaceae Hydrolea coymbosa Brockington 379 (FLAS) Herbarium HiSeq: 1 × 100* 2 660 144
Sphenocleaceae Sphenoclea zeylanica Ionta 352 (FLAS) Herbarium HiSeq: 1 × 100* 1 058 401
Tetrachondraceae Polypremum procumbens Davis 406 (FLAS) Herbarium HiSeq: 1 × 100* 1 283 557
Vahliaceae Vahlia capensis s.n. Unknown HiSeq: 1 × 100* 1 254 388
Campanulids
Stemonuraceae Discophora guianensis Kajekai 240 (CICY) Herbarium HiSeq: 1 × 100* 9 649 463
N O V E M B E R 2015 , VOLUME 102 STULL ET AL. RESOLVING BASAL LAMIID PHYLOGENY 5
for accession numbers). References for the previously generated
plastome data used in this study are presented in Appendix S4.
Molecular sampling rationale We limited our analyses to the
protein-coding regions of the plastome for several reasons. It has
been demonstrated that numerous, slowly evolving characters rep-
resent the best data for resolving ancient rapid radiations because
slowly evolving characters are o en less prone to homoplasy/signal
saturation over long periods of evolutionary time (e.g., Wortley
et al., 2005 ; Jian et al., 2008 ). However, we note that some such nucle-
otide positions may be highly constrained by selection and there-
fore are themselves prone to homoplasy (e.g., Olmstead et al., 1998 ;
P. S. Soltis and D. E. Soltis, 1998 ; Soltis et al., 1999b ). Given that the
basal lamiids (and perhaps also core lamiids) seem to be the prod-
uct of an ancient rapid radiation ( Bremer et al., 2004 ), we reasoned
that the protein-coding regions of the plastome—which are slowly
evolving, yet collectively comprise a wealth of character data—
would provide an excellent source of information for resolving
these problematic relationships. Furthermore, numerous studies
have already demonstrated the utility of the plastome coding re-
gions for resolving ancient rapid radiations within the angiosperms
(e.g., Moore et al., 2010 : eudicots; Jian et al., 2008 : Saxifragales;
Wang et al., 2009 : rosids; Xi et al., 2012 : Malpighiales). Also, limit-
ing our analyses to the protein-coding regions of the plastome
maximized compatibility with already available data sets of
plastome coding sequences (e.g., Moore et al., 2010 ; Ruhfel et al.,
2014 ).
e plastome e ectively represents a single gene tree ( Doyle,
1992 ) and therefore might not accurately track the pattern of lamiid
species diversi cation. However, the attributes mentioned above
make the plastome well suited for this particular phylogenetic
problem, and the results should serve as a robust hypothesis to be
examined against future studies employing numerous nuclear loci.
Furthermore, we note that plastome-based studies of broad-scale
angiosperm phylogeny (e.g., Jansen et al., 2007 ; Moore et al., 2007 ;
Moore et al., 2010 ; Ruhfel et al., 2014 ) have generally been corrobo-
rated by studies employing nuclear or mitochondrial data (e.g., Qiu
et al., 2010 ; Soltis et al., 2011 ; Xi et al., 2014 ; Wickett et al., 2014 ),
suggesting that the plastome e ectively tracks major angiosperm
relationships in most cases, with important exceptions (e.g., Sun
et al., 2015 ).
Phylogenetic analysis We analyzed the data under both maxi-
mum likelihood (ML) and Bayesian frameworks using the pro-
grams RAxML v 8.1.12 ( Stamatakis, 2014 ) and MrBayes v 3.2.1
( Huelsenbeck and Ronquist, 2001 ; Ronquist et al., 2012 ), respec-
tively. Because the plastid genome is uniparentally inherited and
does not undergo recombination, its constituent genes should thus
track the same evolutionary history ( D. E. Soltis and P. S. Soltis,
1998 ). is means that plastid genes can be safely concatenated for
phylogenetic analyses without concern about strongly con icting
phylogenetic signals ( Olmstead and Sweere, 1994 ). We therefore
concatenated the 73 plastid genes for all analyses.
e ML and Bayesian analyses included four model partitioning
strategies, using the GTR+Γ model for each partition: (1) no parti-
tioning, (2) partitioning by codon position (three partitions), (3)
partitioning by each gene (73 partitions), and (4) partitioning by
each codon position within each gene (219 partitions). e RAxML
analyses included 1000 bootstrap replicates in addition to a search
for the best-scoring ML tree. e Bayesian analyses included 15
million generations with four chains sampling the posterior every
1000 generations. To evaluate the convergence of the analyses and
determine the burn-in, we visually inspected the parameter outputs
using the program Tracer v 1.5 ( Rambaut and Drummond, 2009 ).
We removed the burn-in (usually around 10%) before sampling the
trees from the posterior distribution.
R E S U L T S
Of the 59 113 DNA characters analyzed, 31 051 were constant
and 28 062 were variable. We recovered nearly identical relation-
ships across all analyses (both ML and Bayesian), with di erences
in topology restricted to areas of poor support—there were no
strongly supported con icting relationships among the major lin-
eages. Of the four partitioning schemes in the ML analyses, the
gene-codon scheme (219 partitions) had the highest likelihood
score (lnL = 598 491.98) and is depicted in Figs. 1 and 2 and
discussed in the text. The –lnL scores of the other ML analyses
were 613 007.34 (no partition), 609 229.67 (codon partition), and
607 903.56 (gene partition). e best –lnL score of the gene-codon
partitioned Bayesian analysis was 596 805.40; the other partitioning
schemes did not reach stationarity. e posterior probabilities of
the gene-codon partitioned Bayesian analysis are mapped onto the
best ML tree in Figs. 1 and 2 and discussed in the text. All trees re-
sulting from these analyses (except those already shown in the text)
are available in the online supplemental les (online Appendices
S5–S11).
e overall topology recovered is as follows ( Figs. 1 and 2 ).
Lamiidae are strongly supported as monophyletic. e core lamiids
form a well-supported clade (BS 100/PP 1.0), but relationships
among the major core lineages (i.e., Boraginales, Gentianales, La-
miales, Solanales, and Vahlia ) are more poorly supported given
their modest/low ML bootstrap values. However, the Bayesian pos-
terior probability values are generally strong. Boraginales were re-
covered as sister to Gentianales (BS 50/PP 0.99), with these together
being sister to a clade of Lamiales, Solanales, and Vahlia (BS 66/PP
1.0). Vahlia was recovered as sister to Lamiales but with very weak
support (BS <50/PP 0.74).
e 33 genera comprising Icacinaceae sensu Kårehed (noted
with asterisks in Fig. 1 ) form two distinct clades: one includes 21
genera and corresponds to the Icacina and Cassinopsis groups of
Kårehed (2001) ; the other clade comprises 11 genera, including 10
icacinaceous genera, primarily from the Apodytes and Emmotum
groups of Kårehed (2001) , as well as Metteniusa embedded well
within the clade, sister to Ottoschulzia Urb. The first Icacina-
ceae clade (including 21 genera) and Oncothecaceae form a well-
supported clade (BS 100/PP 1.0) sister to the rest of the lamiids. e
second clade of Icacinaceae (including Metteniusa ) is placed with
strong support (BS 90/PP 1.0) as sister to the remaining lamiids,
with Garryales highly supported as sister to the core lamiids (BS 98/
PP 1.0).
Within the rst Icacinaceae clade, Cassinopsis Sond. is sister to a
clade comprising most of the genera of the Icacina group (BS 78/PP
0.99). e Icacina group, in turn, includes four well-supported
clades ( Fig. 3 ), which are discussed in more detail below; in general,
relationships are well resolved and well supported across the entire
clade. Within the second major clade of Icacinaceae sensu Kårehed,
Platea Blume + Calatola Standl. are strongly supported (BS 100/PP
1.0) as sister to a clade of genera from the Emmotum and Apodytes
6 A M E R I C A N J O U R N A L O F B O T A N Y
(Continued)
N O V E M B E R 2015 , VOLUME 102 STULL ET AL. RESOLVING BASAL LAMIID PHYLOGENY 7
FIGURE 1 The best tree obtained from the gene-codon partitioned maximum likelihood (ML) analysis of 73 plastid genes. Accessions denoted with an
asterisk are members of Icacinaceae sensu Kårehed (2001) . Numbers above the branches are Bayesian posterior probability/ML bootstrap values from
the gene-codon partitioned analyses. An asterisk indicates a posterior probability of 1.0 or ML bootstrap value of 100%. A dash indicates that a given
branch was either (1) not obtained in the Bayesian analysis or (2) received <0.50 Bayesian or 50% ML support.
8 A M E R I C A N J O U R N A L O F B O T A N Y
FIGURE 2 The best tree, with branch lengths, obtained from the gene-codon partitioned maximum likelihood analysis of 73 plastid genes. Note the
short internal branch lengths along the lamiid backbone and within the core lamiid clade. Support for these relationships is shown in Fig. 1 .
N O V E M B E R 2015 , VOLUME 102 STULL ET AL. RESOLVING BASAL LAMIID PHYLOGENY 9
FIGURE 3 Summary of Icacinoideae relationships obtained from the maximum likelihood analyses. Branches receiving <50% bootstrap support are
collapsed. All other branches are fully supported except where noted (bootstrap values are from the gene-codon partitioned analysis). Four major
well-supported clades are indicated on the tree. The morphology of these clades is discussed in the text.
groups. However, Pittosporopsis Craib (which, until now, had never
been included in a molecular phylogenetic analysis) and Metteniusa
(Metteniusaceae) are nested in the Emmotum group, and Dendro-
bangia is nested in the Apodytes group, in all cases with strong sup-
port ( Fig. 1 ).
DISCUSSION
Major lamiid clades Our results show with strong support that
Garryales are the immediate sister of the core lamiids ( Fig. 1 ). Sev-
eral studies have suggested this relationship, albeit with bootstrap
10 A M E R I C A N J O U R N A L O F B O T A N Y
support <50% ( Bremer et al., 2002 ; Refulio-Rodriguez and Olmstead,
2014 ), while other studies have recovered other basal lamiid groups
as sister to the core lamiids—e.g., Oncothecaceae ( Soltis et al.,
2011 ) or Metteniusaceae ( González et al., 2007 )—with Garryales
sister to all other lamiids. We apply the name Garryidae R. G.
Olmstead, W. S. Judd, and P. D. Cantino [G. W. Stull, D. E. Soltis,
and P. S. Soltis] to this clade (i.e., Garryales + Lamianae ), which
represents a slight modi cation to its former circumscription (see
Phylogenetic Classi cation section for de nitions of clade names
mentioned throughout the Discussion). Originally, the name Gar-
ryidae was used for the lamiids/euasterids I as a whole, with the
name Lamiidae comprising a more exclusive clade within Garry-
idae ( Cantino et al., 2007 ). However, Refulio-Rodriguez and Olmstead
(2014) apply the name Lamiidae to the entire lamiid/euasterid I
clade (including Garryales and all other basal lamiid lineages), fol-
lowing common usage of the name and priority, and this practice
will be followed in the upcoming Companion Volume to the Phy-
loCode (R. G. Olmstead, University of Washington, personal com-
munication). us, the name Garryidae is available for this more
exclusive clade of lamiids.
Our results also show with strong support that Metteniusaceae
(as here circumscribed/de ned; see below) are sister to Garryidae
(as here de ned). is major clade had not been recovered in previ-
ous studies ( González et al., 2007 ; Byng et al., 2014 ; Refulio-Rodriguez
and Olmstead, 2014 ), which placed Metteniusa and the other basal
lamiids in various di erent con gurations in relation to the core
lamiids, generally with poor support. We establish a new name un-
der the PhyloCode for this major clade: Metteniusidae G. W. Stull,
D. E. Soltis, and P. S. Soltis. Finally, Icacinaceae (as here circum-
scribed; see below) and Oncothecaceae form a clade sister to the
rest of the lamiids (or Metteniusidae ). We adopt the name Icacinales
Tiegh. ex Reveal [G. W. Stull] speci cally for this clade—i.e., Icaci-
naceae (as here de ned) + Oncothecaceae. e relationships and
morphology of Icacinaceae and Oncothecaceae are discussed in
more detail below.
Core lamiid relationships Although numerous studies have in-
vestigated lamiid phylogeny, considerable uncertainty still surrounds
relationships among the core lamiid lineages (i.e., Boraginales,
Gentianales, Lamiales, Solanales, and Vahlia ). This represents
one of the largest gaps in our current understanding of broad-scale
angiosperm phylogeny ( Stevens, 2001 onward ; Soltis et al., 2011 ).
Practically every previous major study of lamiid or angiosperm
phylogeny has uncovered unique relationships among these
groups, but never with strong support (e.g., Olmstead et al., 1992 ,
1993 , 2000 ; Chase et al., 1993 ; Soltis et al., 1999a ; Savolainen,
2000a, b ; Soltis et al., 2000 , 2011 ; Albach et al., 2001 ; Bremer et al.,
2002 ; Moore et al., 2010 ; Qiu et al., 2010 ; Ruhfel et al., 2014 ). e
most comprehensive study of lamiid phylogeny to date ( Refulio-
Rodriguez and Olmstead, 2014 ) recovered (Gentianales, ((Solanales +
Vahliaceae), (Boraginales + Lamiales))). Although Bayesian sup-
port for this tree was relatively strong, the ML bootstrap values,
which are generally considered a more conservative measure of
support ( Suzuki et al., 2002 ; Erixon et al., 2003 ), were only moder-
ate (i.e., in the range of 50–70%). Our results di er considerably
from those of Refulio-Rodriguez and Olmstead (2014) , as well as
from other previous studies of lamiid phylogeny. We found two
major clades—((Boraginales + Gentianales), (Lamiales + Solanales +
Vahlia ))—representing another unique topology compared to
previous studies of lamiid phylogeny. However, ML support for the
core lamiid relationships presented here is not strong, despite the
large number of characters included in the analyses, indicating that
there is still uncertainty surrounding some core lamiid relation-
ships. Although the Bayesian support for these relationships is gen-
erally strong ( Fig. 1 ), posterior probability values are o en in ated
compared to ML bootstrap values (e.g., Suzuki et al., 2002 ; Cummings
et al., 2003 ; Erixon et al., 2003 ), as noted already.
Di culty in resolving core lamiid relationships might be due to
an ancient rapid radiation ( Bremer et al., 2004 ), re ecting the short
internal branch lengths connecting the core lamiid lineages in Fig.
2 . Such radiations pose numerous problems for phylogeny recon-
struction—e.g., very few unambiguous characters supporting the
“true” relationships, homoplasy, and saturation of sites (e.g., Whit eld
and Lockhart, 2007 ). Hopefully, accumulation of additional molecu-
lar characters, especially from the nuclear genome (and, less likely,
the more slowly evolving mitochondrial genome), will facilitate
resolution of core lamiid phylogeny, but we have nearly exhausted
the use of the plastid genome.
Circumscription and relationships of Icacinaceae Our results
provide a greatly improved understanding of the circumscription
and relationships of Icacinaceae. e Apodytes and Emmotum
groups, and several other genera of Icacinaceae s.l., are more closely
related to Metteniusa and therefore should be excluded from Icaci-
naceae ( Figs. 1, 2 ). The remaining 21 genera of Icacinaceae s.l.
included in our analyses (which comprise ~160 spp.) form a well-
supported clade, which we formally name under the PhyloCode
using the converted clade name Icacinaceae M i e r s [ G . W. S t u l l ] . is
clade should be treated as a family under the APG system (as shown
in Fig. 1 and Table 2 ).
Icacinaceae includes Cassinopsis as well as most of the genera of
the Icacina group. Here, we adopt the subfamily name Icacinoideae
Engl. [G. W. Stull] for the clade that essentially corresponds to the
Icacina group ( Fig. 3 ); we use this clade name henceforth. Although
there are no clear morphological synapomorphies of Icacinaceae ,
all members of Icacinoideae possess unilacunar nodes and simple
perforation plates ( Bailey and Howard, 1941a , b ). Furthermore,
members of Icacinoideae show a strong tendency to produce alter-
nate (rather than opposite or scalariform) intervessel pits, short
vessel elements and bers, and vasicentric and/or banded axial pa-
renchyma ( Lens et al., 2008 ).
Previous studies have o ered insights into relationships among
members of Icacinoideae ( Kårehed, 2001 ; Lens et al., 2008 ; Angulo
et al., 2013 ; Byng et al., 2014 )—for example, the sister relationship
of Mappia Jacq. + Nothapodytes Blume, the sister relationship of
Miquelia + Phytocrene , the nested position of Polyporandra within
Iodes , and the nested positions of Polycephalium and Chlamydo-
carya within Pyrenacantha . However, the major clades within Icac-
inoideae and the positions of numerous genera (e.g., Alsodeiopsis
Oliv., Desmostachys Planch., Hosiea , Merrilliodendron Kanehira,
Mappianthus , Natsiatum , Natsiatopsis , Pleurisanthes Baill., Rhyti-
caryum Becc., Stachyanthus ) have been unclear. Our results indi-
cate that Icacinoideae consists of four major clades ( Fig. 3 ). e
following discussion highlights the general geographic distribu-
tions and a few distinct morphological features of these clades;
however, formal reconstructions of numerous morphological char-
acters will be necessary to determine unambiguous synapomor-
phies of each.
e rst clade, comprising the Neotropical genus
Mappia (4
spp.) and the Asiatic genus Nothapodytes (~8 spp.), is sister to the
N O V E M B E R 2015 , VOLUME 102 STULL ET AL. RESOLVING BASAL LAMIID PHYLOGENY 11
rest of Icacinoideae and is characterized by an erect habit (trees or
shrubs) with elongate, symmetrical styles and a eshy foliaceous
disk at the base of the ovary ( Howard, 1942a ). e second clade is
pantropical and consists of ve genera (~15 spp.) of the traditional
tribe Icacineae ( Casimirella Hassl., Icacina , Merrilliodendron , Lavi-
geria Pierre, and Leretia Vell.). is clade consists of climbers with
colporate pollen with foveolate (i.e., nely pitted) to reticulate or-
namentation ( Lobreau-Callen, 1972 , 1973 ), determinate in ores-
cences ( Howard, 1942a , 1942c , 1992 ), and bisexual owers, except
for Merilliodendron , which is a monotypic genus of trees with echi-
nate colpate pollen. e third clade comprises the Paleotropical
genus Iodes (~16 spp.) and the small Asiatic genus Mappianthus (2
spp.). Consistent with Byng et al. (2014) , we found the monotypic
genus Polyporandra to be nested within Iodes, and our tree re ects
their new combination: Iodes scandens (Becc.) Utteridge & Byng
(basionym: Polyporandra scandens Becc.). is clade comprises
climbers with opposite leaves, extra-axillary tendrils, cymose in o-
rescences, and unisexual owers (plants dioecious) ( Sleumer, 1971 ;
Hua and Howard, 2008 ).
e fourth clade is the largest (with nine genera included in
our analyses, but probably 11 total with Sleumeria and Natsiatop-
sis , and ~75 species) and most morphologically heterogeneous,
including genera from all four of the traditional tribes. is clade
is also paleotropical and appears to be characterized by indeter-
minate inflorescences ( Hutchinson and Dalziel, 1958 ; Lucas,
1968 ; Sleumer, 1971 ; Villiers, 1973 ), with the exception of Hosiea ,
which has cymes ( Hua and Howard, 2008 ). It also consists almost
entirely of climbers, with the exception of Rhyticaryum (trees and
shrubs) and Desmostachys (trees and shrubs, occasionally scan-
dent) ( Hutchinson and Dalziel, 1958 ; Sleumer, 1971 ). Within this
fourth clade, the genera of the traditional Phytocreneae form a
subclade (including Sarcostigma ) characterized by pitted endo-
carps ( Sleumer, 1971 ; Villiers, 1973 ; Stull et al., 2012 ) and gener-
ally furrowed xylem ( Lens et al., 2008 ). Consistent with Byng et al.
(2014) , we found Chlamydocarya a n d Polycephalium to be nested
within Pyrenacantha . e trees we present re ect their new com-
binations: Pyrenacantha thomsoniana (Baill.) Byng & Utteridge
(basionym: Chlamydocarya thomsoniana Baill.) and Pyrenacantha
lobata (Pierre) Byng & Utteridge (basionym: Polycephalium loba-
tum (Pierre) Pierre ex Engl.).
Our analyses consistently found a sister relationship between the
two major Paleotropical clades (clades III and IV, Fig. 3 ). Although
this relationship was not strongly supported based on our molecu-
lar data, most members of these clades have porate pollen with
echinate ornamentation ( Lobreau-Callen, 1973 ). ese taxa also
generally have unisexual owers (plants dioecious), with the excep-
tion of Desmostachys and Hosiea ( Hutchinson and Dalziel, 1958 ;
Hua and Howard, 2008 ). Furthermore, they tend to have highly
specialized wood anatomy associated with their predominantly
climbing habit ( Bailey and Howard, 1941b d ; Lens et al., 2008 ).
O u r a n a l y s e s f a i l e d t o p l a c e Alsodeiopsis a n d Pleurisanthes among
the four major clades of Icacinoideae with strong support ( Fig. 3 ).
ey both exhibit unique combinations of morphological characters,
making it di cult to predict their phylogenetic positions. Alsodeiop-
sis h a s b i s e x u a l owers and determinate in orescences, like clades I
and II, but is distinct in having tetracolporate pollen ( Dahl, 1952 ).
Pleurisanthes h a s b i s e x u a l owers and indeterminate in orescences
( Howard, 1942c ) like Desmostachys , b u t i s s i m i l a r t o c l a d e I I i n h a v -
ing foveolate/reticulate colporate pollen ( Dahl, 1952 ; Lobreau-Callen,
1972 , 1973 ). It is possible that these taxa occupy isolated phyloge-
netic positions. Pleurisanthes was placed in its own family by van
Tieghem (1897) , highlighting its morphological distinctness from
other members of Icacinaceae. Additional molecular data will be
necessary to resolve the placements of these genera.
Of the traditional tribes of Engler (1893) and Sleumer (1942) ,
none is strictly monophyletic. Icacineae are massively polyphyletic,
with 12 genera retained within Icacinaceae and the ~27 others now
in di erent groups: Cardiopteridaceae, Metteniusaceae (as here de-
ned), Pennantiaceae, and Stemonuraceae). Iodeae, Phytocreneae,
and Sarcostigmateae all fall within Icacinaceae . However, members
of Iodeae—i.e., Hosiea , Iodes (incl. Polyporandra ), Mappianthus ,
Natsiatopsis , Natsiatum —form two distinct clades, and the mono-
generic tribe Sarcostigmateae is nested within Phytocreneae. Al-
though two of Bailey and Howard’s (1941b) groups are polyphyletic,
their third group (characterized by simple perforation plates) is
monophyletic, corresponding more or less to Icacinoideae .
TABLE 2. Rank-based classi cation of Icacinaceae s.l. All genera listed were formerly included in Icacinaceae s.l. ( Engler, 1893 ; Sleumer, 1942 ), although
Cardiopteris and Metteniusa have typically been excluded from the family ( Howard, 1940 ; Bailey and Howard, 1941a ). Of the ~54 genera traditionally included
in Icacinaceae s.l., only 23 are retained in the circumscription recognized here. Note that Polyporandra Becc. was recently subsumed in Iodes Blume and that
Chlamydocarya Baill. and Polycephalium Engl. were recently subsumed in Pyrenacantha Wight ( Byng et al., 2014 ). Furthermore, Sleumeria Utteridge, Nagam. &
Teo, included here, was only recently described ( Utteridge et al., 2005 ). A broader Metteniusaceae (which formerly included only Metteniusa H. Karst.) is here
recognized, including 10 generic segregates of Icacinaceae s.l. Kårehed (2001) broadened the circumscription of Cardiopteridaceae (which formerly included
only Cardiopteris Wall. ex Royle) to include four generic segregates of Icacinaceae s.l. He additionally established the family Stemonuraceae for 12 generic
segregates of Icacinaceae s.l. and recognized Pennantiaceae J. Agardh to accommodate the phylogenetically isolated genus Pennantia .
Family Constituent genera Order/major clade
Icacinaceae Miers
(23 genera/160 spp.)
Alsodeiopsis , Casimirella , Cassinopsis , Desmostachys , Hosiea , Icacina , Iodes , Lavigeria , Leretia ,
Mappia , Mappianthus , Merrilliodendron , Miquelia , Natsiatopsis , Natsiatum , Nothapodytes ,
Phytocrene , Pleurisanthes , Pyrenacantha , Rhyticaryum , Sarcostigma , Sleumeria , Stachyanthus
Icacinales /Lamiidae
Metteniusaceae H. Karst. (11/59) Apodytes , Calatola , Dendrobangia , Emmotum , Metteniusa , Oecopetalum , Ottoschulzia ,
Pittosporopsis , Platea , Poraqueiba , Rhaphiostylis
Metteniusales /Lamiidae
Cardiopteridaceae Blume (5/43) Cardiopteris , Citronella , Gonocaryum , Leptaulus , Pseudobotrys Aquifoliales /Campanulidae
Stemonuraceae Kårehed (12/95) Cantleya , Codiocarpus , Discophora , Gastrolepis , Gomphandra , Grisollea , Hartleya , Irvingbaileya ,
Lasianthera , Medusanthera , Stemonurus , Whitmorea
Aquifoliales /Campanulidae
Pennantiaceae J. Agardh (1/4) Pennantia Apiales /Campanulidae
12 A M E R I C A N J O U R N A L O F B O T A N Y
As noted, two genera of Icacinaceae s.l., Natsiatopsis and Sleu-
meria , were not included in our analyses. However, Byng et al.
(2014) found Sleumeria to be nested within the Icacina group, pro-
viding support for its inclusion in our Icacinoideae . Furthermore,
Utteridge et al. (2005) highlighted the morphological similarities of
Sleumeria to multiple Malesian genera of Icacinaceae , particularly
Phytocrene and Sarcostigma , with which it shares successive cam-
bia, for example. Natsiatopsis has yet to be included in a phyloge-
netic study of Icacinaceae, but it is morphologically very similar to
Natsiatum , which is nested well within this clade. Both Natsiatopsis
and Natsiatum are scandent shrubs/climbers, with long petioles,
densely pubescent cordate leaves with toothed margins, and uni-
sexual owers (dioecious) in racemes ( Hua and Howard, 2008 ).
Natsiatopsis also has unilacunar nodes (G. W. Stull, personal obser-
vation) like all other members of Icacinoideae . erefore, we are
con dent that Natsiatopsis belongs to this clade.
Phylogenetic position of Oncothecaceae Oncotheca , long con-
sidered phylogenetically isolated ( Carpenter and Dickison, 1976 ;
Cameron, 2003 ), includes two species endemic to New Caledonia
( Baillon, 1891 ; McPherson et al., 1981 ). e genus has generally
been recognized as the sole constituent of its own family ( Airy
Shaw, 1965 ). Based on morphology, Oncotheca has variously been
associated with Aquifoliaceae ( Baillon, 1891 , 1892 ), Ebenaceae
( Guillaumin, 1938 , 1948 ), and eaceae ( Takhtajan, 1969 , 1997 ;
Cronquist, 1981 ). Although molecular analyses have shown that
Oncotheca occupies a basal branch of lamiids (e.g., Soltis et al.,
1999a , 2000 , 2011 ; Savolainen et al., 2000a ; Bremer et al., 2002 ;
Refulio-Rodriguez and Olmstead, 2014 ), its precise placement has
been ambiguous. Multiple studies ( Bremer et al., 2002 ; Lens et al.,
2008 ; Byng et al., 2014 ) have recovered Oncotheca sister to Apo-
dytes or the Apodytes group. Soltis et al. (2011) found Oncotheca
sister to the core lamiids, while Refulio-Rodriguez and Olmstead
(2014) found a sister relationship between Metteniusa and Onco-
theca . However, in all previous cases, the position of Oncotheca was
weakly supported.
Our results provide strong support for a sister relationship be-
tween Oncothecaceae and Icacinaceae as here circumscribed, which
is a novel nding. Other studies perhaps failed to recover this rela-
tionship due to insu cient sampling of characters (e.g., Byng et al.,
2014 ; Lens et al., 2008 ), taxa (e.g., Soltis et al., 2011 ; Refulio-Rodriguez
and Olmstead, 2014 ), or both. Morphological features uniting
Oncothecaceae and Icacinaceae are unclear, and in several respects,
Oncothecaceae are more morphologically similar to Metteniusa ,
presumably due to either convergence or the retention of plesio-
morphies. For example, both have pentalacunar nodes, epipetalous
stamens, and ve-carpellate fruits ( Carpenter and Dickison, 1976 ;
González et al., 2007 ; González and Rudall, 2010 ). However, as
noted, the basal lamiids seem to be the product of an ancient rapid
radiation, with very long branches leading to the crown clades.
Given the phylogenetic isolation of Icacinaceae and Oncotheca-
ceae, it is therefore not surprising that they are morphologically
distinct, even if they do represent sister taxa.
Circumscription and relationships of Metteniusaceae e sys-
tematic position of Metteniusa has been ambiguous since its initial
description ( Karsten, 1860 ). It has been treated as an unusual mem-
ber of Icacinaceae (e.g., Sleumer, 1942 ; Cronquist, 1981 ; orne,
2000 ), the sole constituent of its own family ( Karsten, 1860 ), a
member of Olacaceae ( Sleumer, 1934 ), a member of Opiliaceae
( Sleumer, 1936 ), or a member/near relative of Alangiaceae ( Watson
and Dallwitz, 1992 onward ). Takhtajan (1997) placed Metteniusa in
its own family and order (Metteniusaceae/Metteniusales), which he
included in the superorder Celastranae (Rosidae) along with Icaci-
nales and ve other orders. In the APG III (2009) system, Metteniusa
is recognized as the sole member of Metteniusaceae, within lamiids
but unplaced to order.
Metteniusa was recently shown to be an early-diverging lamiid
( González et al., 2007 ), although sampling of Icacinaceae s.l. was
limited, and so the precise placement of Metteniusa /Metteniusaceae
remained ambiguous. However, a relationship with Oncotheca
has been suggested ( González et al., 2007 ; González and Rudall,
2010 ), given that both genera share pentalacunar nodes, epipetal-
ous stamens, and ve-carpellate gynoecia (with this latter character
somewhat obscured in Metteniusa due to its pseudomonomery;
González and Rudall, 2010 ; Endress and Rapini, 2014 ). More re-
cently, Refulio-Rodriguez and Olmstead (2014) also recovered
Metteniusa sister to Oncotheca , while another recent study ( Byng
et al., 2014 ), with a greater sampling of Icacinaceae s.l., found
Metteniusa nested within the Emmotum group, with Oncotheca sis-
ter to the Apodytes group. However, neither of these positions of
Metteniusa was well supported. Metteniusa was not included in the
phylogenetic study of Lens et al. (2008) , and although it was in-
cluded in Kårehed’s (2001) study, which placed it within Cardiop-
teridaceae (Aquifoliales), this placement was based on morphology
alone.
Our results provide strong support that Metteniusa is nested
within the Emmotum group of Kårehed (2001) , sister to Ottoschul-
zia . We also recovered the Asiatic genus Pittosporopsis in this
group. Our study is the rst to include Pittosporopsis in a molecular
phylogenetic analysis; Kårehed (2001) tentatively placed it within
the Icacina g r o u p b a s e d o n m o r p h o l o g i c a l a n a l y s e s . A m o r p h o -
logical feature potentially supporting the relationship of both
Metteniusa and Pittosporopsis within the Emmotum group is the
presence of anther connectives protruding beyond the anther sacs
( Howard, 1942b , c ; Hua and Howard, 2008 ; González and Rudall,
2010 ; Duno de Stefano et al., 2007 ). ese genera also tend to have
eshy petals ( Kårehed, 2001 ) and fruits with persistent styles ( Hua
and Howard, 2008 ; González and Rudall, 2010 ), but additional
work will be necessary to document unequivocal synapomorphies
for this clade.
We also found strong support for the sister relationship of the
Emmotum a n d Apodytes groups (with the latter including Den-
drobangia ). Whereas Kårehed (2001) tentatively placed Calatola
and Platea i n t h e Emmotum group, we recovered these together as
sister to the
Emmotum + Apodytes groups. Calatola a n d Platea are
both dioecious trees with indeterminate in orescences ( Howard,
1942c ; Hua and Howard, 2008 ). Morphological synapomorphies
for this larger clade of Metteniusa plus 10 genera from Icacinaceae
s.l. are unclear. ese genera possess a similar pollen type (i.e.,
colporate grains with foveolate to reticulate ornamentation), but
this shared feature might represent a symplesiomorphy given that
other basal lamiids and campanulids show similar pollen types
( Lobreau-Callen, 1972 , 1973 ). Nevertheless, molecular support
for this group is maximal. Because this clade is phylogenetically
isolated from Icacinaceae (as circumscribed here), under a rank-
based system it must be recognized as not only a separate family
but also a separate order. Here, we formally establish Metteniusaceae
H. Karst. ex Schnizl. [G. W. Stull] as the converted name for this
clade, comprising Metteniusa plus 10 genera from Icacinaceae s.l.
N O V E M B E R 2015 , VOLUME 102 STULL ET AL. RESOLVING BASAL LAMIID PHYLOGENY 13
Under the APG system, this clade should be treated as a family
and the sole constituent of the order Metteniusales. We also estab-
lish new names for the three major clades within Metteniusaceae :
Apodytoideae G . W. S t u l l , Metteniusoideae G . W. S t u l l , a n d Plateoideae
G. W. Stull.
Asterid character evolution Our understanding of lamiid and
euasterid (= Gentianidae ) character evolution has been obscured
both by poor resolution of basal lamiid relationships and a limited
understanding of morphology (especially oral morphology)
across Icacinaceae s.l. ( Endress and Rapini, 2014 ). e relation-
ships recovered here provide a solid framework for future investi-
gations of character evolution across both the Lamiidae and
Gentianidae as a whole. Given that members of Icacinaceae s.l. are
scattered along the basal branches of both the lamiids and cam-
panulids, many of their morphological features possibly represent
ancestral conditions for the Gentianidae (whether symplesiomor-
phies or synapomorphies of this clade). For example, Icacinaceae
s.l. are evergreen woody plants, mostly trees (although most Icaci-
naceae as here circumscribed are climbers); their owers are
small, with fused sepals and free or basally connate petals, which
often possess an adaxial ridge and apices inflexed in bud; the
stamens are usually alternate with the petals and equal in num-
ber; each carpel contains two apical, pendant ovules; the fruits
are drupes with a single seed ( Howard, 1940 , 1942a d , 1943a c ;
Sleumer, 1971 ; Stevens, 2001 onward ; González and Rudall, 2010 ;
Endress and Rapini, 2014 ). Recent studies have revealed pentam-
erous gynoecia in Metteniusa (with one fertile locule; Gonzalez
and Rudall, 2010 ) and Emmotum (with three fertile carpels;
Endress and Rapini, 2014 ). It has long been assumed that other
Icacinaceae s.l. also have pseudomonomerous gynoecia composed
of two or three carpels (e.g., Engler, 1893 ). Oncotheca , however, is
distinctly ve-carpellate ( Dickison, 1986 ).
A more thorough investigation of morphological features
across basal lamiids (Icacinaceae, Oncothecaeae, Metteniusaceae,
Garryales) and basal campanulids (Aquifoliales) would provide a
much-improved understanding of asterid morphological evolution.
Furthermore, detailed developmental and morphological studies
might also reveal synapomorphies for the newly resolved lamiid
clades (e.g., Icacinales and Metteniusaceae ). Nevertheless, it seems
possible based on our phylogenetic results that the core lamiids,
and their characteristic morphological and ecological diversity, ra-
diated from an ancestry of tropical trees with inconspicuous ow-
ers and large, drupaceous (o en single-seeded) fruits.
PHYLOGENETIC CLASSIFICATION
Our results provide a well-resolved and strongly supported hypoth-
esis of basal lamiid relationships. is improved phylogenetic
framework o ers an excellent opportunity to revise the classi ca-
tion of basal lamiids. Here we present phylogenetic de nitions
following the PhyloCode version 4c ( Cantino and de Queiroz,
2010 ; http://www.ohio.edu/phylocode/toc.html ), including the
recognition of four new clade names, as well as the conversion of
six names already recognized under the ICN. e clades named
here are highlighted in boldface in Fig. 4 , and the de nitions for
the clades are presented below. Following the de nitions, we o er
suggestions for the application of these clade names within the
Angiosperm Phylogeny Group system, including a scheme of fami-
lies and orders building on previous studies (e.g., Kårehed, 2001 ;
Byng et al., 2014 ).
Metteniusidae G. W. Stull, D. E.
Soltis, and P. S. Soltis, new clade
name.
D e nition: e least-inclusive clade
containing Metteniusa edulis H. Karst.
1860 ( Metteniu saceae ), Garrya elliptica
Douglas ex Lindl. 1834 ( Garryales ), and
Gentiana acaulis L. 1753 ( Lamianae ).
is is a node-based de nition in which
all the speci ers are extant. Abbreviated
de nition: < Metteniusa edulis H . K a r s t .
1860 & Garrya elliptica Douglas ex
Lindl. 1834 & Gentiana acaulis L. 1753.
Etymology : Derived from Metteniusa
(name of an included genus), estab-
lished by Hermann Karsten in honor
of German botanist Georg Heinrich
Mettenius.
Reference phylogeny: is paper is
the primary reference; see Figs. 1, 2,
and 4 . See also Burge (2011) .
C o m p o s i t i o n : Metteniusaceae , Gar-
ryales , a n d Lamianae (core lamiids:
Boraginales, Gentianales, Lamiales,
Solanales, and Vahlia ).
Diagnostic apomorphies: No non-
DNA synapomorphies are currently
known.
FIGURE 4 Phylogenetic classi cation of the Lamiidae , based on the results from this paper. Phylogenetic
names newly proposed in this paper are indicated in boldface. De nitions for these new names are pre-
sented in the text. The names Lamiidae [R. G. Olmstead, W. S. Judd, and P. D. Cantino] and Lamianae [R. G.
Olmstead and W. S. Judd] will be established in the upcoming Companion Volume to the PhyloCode (R. G.
Olmstead, University of Washington, personal communication).
14 A M E R I C A N J O U R N A L O F B O T A N Y
Synonyms: None.
C o m m e n t s : is is a newly discovered clade, lacking a pre-existing
name. e composition of Metteniusaceae (discussed more below)
and the positions of Metteniusaceae a n d Garryales i n r e l a t i o n t o t h e
Lamianae were poorly supported or unresolved in previous studies
(e.g., Soltis et al., 2011 ; Byng et al., 2014 ; Refulio-Rodriguez and
Olmstead, 2014 ). Our results provide strong support that Metteniusa-
ceae ( a s h e r e c i r c u m s c r i b e d ) a n d Garryales a r e s u c c e s s i v e l y s i s t e r t o
Lamianae . H o w e v e r , i f u p o n f u r t h e r s t u d y Metteniusaceae is found
to be sister to Icacinales , t h e n a m e Metteniusidae would become a
synonym with the prior name Lamiidae . M o r p h o l o g i c a l s y n a p o m o r -
phies for Metteniusidae are currently unknown.
We chose Metteniusa edulis as an internal speci er because it is
the type of Metteniusa , w h i c h i s t h e b a s i s o f t h e n a m e Metteniusidae .
Although we did not include this species in our analyses—instead,
we included Metteniusa tessmanniana S l e u m . ( S l e u m . ) t h e m o n o -
phyly of Metteniusa is supported by numerous morphological fea-
tures ( Lozano-Contreras and de Lozano, 1988 ). We chose Garrya
elliptica as an internal speci er because it is the type of the genus.
Although we did not include G. elliptica in this study, a recent study
( Burge, 2011 ) demonstrated that Garrya is monophyletic and that
G. elliptica is closely related to G. avescens , which we included in
our analyses. e last internal speci er, Gentiana acaulis , was in-
cluded in our analyses and occupies a highly nested position in the
phylogeny of Metteniusidae .
Garryidae R. G. Olmstead, W. S. Judd, and P. D. Cantino
2007: 836 [G. W. Stull, D. E. Soltis, and P. S. Soltis], converted
clade name.
D e nition: e least-inclusive clade containing Garrya elliptica
Douglas ex Lindl. 1834 ( Garryales ) and Gentiana acaulis L. 1753
( Lamianae ). is is a node-based de nition in which all the speci-
ers are extant. Abbreviated de nition: < Garrya elliptica Douglas
ex Lindl. 1834 & Gentiana acaulis L. 1753.
Etymology: Derived from the included genus Garrya Douglas ex
Lindl.
Reference phylogeny: is paper is the primary reference; see
Figs. 1, 2, and 4 . See also Bremer et al. (2002) and Refulio-Rodriguez
and Olmstead (2014) .
Composition: Garryales and Lamianae (core lamiids: Boragina-
les, Gentianales, Lamiales, Solanales, and Vahlia ).
Diagnostic apomorphies: No non-DNA synapomorphies are
currently known.
Synonyms: None.
Comments: e name Garryidae was originally applied to the
lamiid/euasterid I clade as a whole ( Cantino et al., 2007 ). However,
Refulio-Rodriguez and Olmstead (2014) instead applied the name
Lamiidae to the lamiid/euasterid I clade, and this procedure will be
followed in the Companion Volume to the PhyloCode (R. G. Olm-
stead, University of Washington, personal communication). We
therefore apply the name Garryidae to a less inclusive clade of lami-
ids, i.e., Garryales + Lamianae . Several previous studies recovered
Garryales sister to the core lamiids, albeit generally with weak sup-
port ( Bremer et al., 2002 ; Refulio-Rodriguez and Olmstead, 2014 ).
Our analyses place Garryales sister to the core lamiids with strong
ML and Bayesian support. Morphological synapomorphies for this
clade, however, are currently unknown.
Garrya elliptica , one of the internal speci ers, represents the
type of the genus Garrya , and it is closely related to the species of
Garrya ( G. avescens ) that we included in our phylogenetic analyses
( Burge, 2011 ). e other internal speci er, Gentiana acaulis , was
included in our phylogenetic analyses.
Garryales Lindl. 1835: 16 [G. W. Stull, D. E. Soltis, and P. S.
Soltis], converted clade name.
De nition: e least-inclusive clade containing Garrya elliptica
Douglas ex Lindl. 1834 (Garryaceae) and Eucommia ulmoides O l i v.
1890 (Eucommiaceae). is is a node-based de nition in which all
the speci ers are extant. Abbreviated de nition: < Garrya elliptica
Douglas ex Lindl. 1834 & Eucommia ulmoides Oliv. 1890.
Etymology: Derived from the included genus Garrya Douglas ex
Lindl.
Reference phylogeny: Soltis et al. (1999a : supplemental g. 11A)
is the primary reference phylogeny. See also Soltis et al. (2000 ,
2011 ), Bremer et al. (2002) , Savolainen et al. (2000a) , Refulio-Rodriguez
and Olmstead (2014) , and this paper.
Composition: Garryaceae, Eucommiaceae.
Diagnostic apomorphies: Production of the latex gutta percha
and dioecy.
Synonyms: None.
Comments: Numerous phylogenetic studies show that Aucuba
(Garryaceae or sometimes treated in its own family, Aucubaceae
Bercht. & J. Presl), Garrya (Garryaceae), and
Eucommia (Eucom-
miaceae) form a well-supported clade (e.g., Soltis et al., 1999a , 2000 ,
2011 ; Refulio-Rodriguez and Olmstead, 2014 ; this paper). Although
APG I (1998) recognized Garryales as including Aucubaceae, Eu-
commiaceae, Garryaceae, and Oncothecaceae, in APG II (2003)
Oncothecaceae were excluded from the order and Aucubaceae were
included in Garryaceae. is procedure was followed in APG III
(2009) . We apply the converted clade name Garryales to this same
circumscription of taxa: Eucommiaceae ( Eucommia ) + Garryaceae
( Garrya + Aucuba ) . e internal specifers selected Garrya elliptica
and Eucommia ulmoides —are the type species of their respective
genera. e production of the latex gutta percha appears to consti-
tute a synapomorphy of Garryales . Another possible synapomorphy
of this clade is dioecy.
Icacinales Tiegh. ex Reveal 1993: 175 [G. W. Stull], converted
clade name.
De nition: e least-inclusive crown clade containing Icacina
oliviformis (Poir.) J. Raynal 1975 ( Icacinaceae ) and Oncotheca ba-
lansae Baill. 1891 (Oncothecaceae). is is a node-based de nition
in which all the speci ers are extant. Abbreviated de nition: <
Icacina oliviformis (Poir.) J. Raynal 1975 & Oncotheca balansae
Baill. 1891.
Etymology: Derived from Icacina (name of an included genus),
which refers to the resemblance of the type species, Icacina olivifor-
mis (Poir.) J. Raynal (= Icacina senegalensis A. Juss.), to Chrysobala-
nus icaco L. of Chrysobalanaceae ( Jussieu, 1823 ).
Reference phylogeny: is paper is the primary reference; see
Figs. 1, 2, and 4 .
Composition: Icacinaceae and Oncothecaceae.
Diagnostic apomorphies: No non-DNA synapomorphies are
currently known.
Synonyms: None.
Comments: e sister relationship of Icacinaceae , as circum-
scribed here, and Oncothecaceae is a novel result, not found in pre-
vious studies of lamiid phylogeny (e.g., Bremer et al., 2002 ;
González et al., 2007 ; Lens et al., 2008 ; Soltis et al., 2011 ; Refulio-
Rodriguez and Olmstead, 2014 ; Byng et al., 2014 ), which have
N O V E M B E R 2015 , VOLUME 102 STULL ET AL. RESOLVING BASAL LAMIID PHYLOGENY 15
generally placed Oncotheca with various genera of Metteniusaceae ,
as circumscribed here, although never with strong support.
e use of Icacinales for the clade comprising Icacinaceae (as
circumscribed here) and Oncothecaceae is a novel application of
the name. Van Tieghem (1897) rst proposed Icacinales as a new
order, but this name was not validly published until more recently
( Reveal, 1993 ). Van Tieghem’s circumscription of Icacinales more
or less corresponded to Icacinaceae s.l., which he divided into
multiple families (Emmotaceae, Iodaceae, Icacinaceae, Leptaula-
ceae, Phytocrenaceae, Pleurisanthaceae, and Sarcostigmataceae).
Takhtajan’s (1997) circumscription of Icacinales included Icacina-
ceae s.l. and three other families (Aquifoliaceae, Phellinaceae, and
Sphenostemonaceae), which are now recognized as distantly re-
lated from Icacinaceae ( Soltis et al., 2011 ). Oncothecaceae had gen-
erally been placed in eales ( Cronquist, 1981 ; Takhtajan, 1997 ).
Icacina oliviformis , the type species of Icacina , is synonymous
with Icacina senegalensis A. Juss. 1823, which is the original name
upon which the genus Icacina was based. e epithet oliviformis
(originally treated as Hirtella olivaeformis Poir. 1813) takes priority
over “ senegalensis as it is the older name. Although Icacina olivi-
formis , one of the internal speci ers, was not included in our analy-
ses, we did include Icacina mannii , which Byng et al. (2014) found
to be sister to Icacina oliviformis with strong support. Note, how-
ever, that in Byng et al. (2014) , I. oliviformis is listed under the syn-
onym I. senegalensis . Previous studies ( Kårehed, 2001 ; Bremer
et al., 2002 ) including Icacina oliviformis (listed under the synonym
Icacina senegalensis ) also found this species to be related to other
members of Icacinaceae as here circumscribed. Oncotheca balan-
sae , which was selected as the other internal speci er for Icacinales ,
is the type of Oncotheca and was included in our phylogenetic
analyses.
Icacinaceae Miers 1851: 174 [G. W. Stull], converted clade
name.
De nition: e most-inclusive crown clade containing Icacina
oliviformis (Poir.) J. Raynal 1975, Mappia racemosa Jacq. 1797, and
Pyrenacantha malvifolia Engl. 1893 but not Oncotheca balansae
Baill. 1891 (Oncothecaceae).
is is a branch-modi ed node-based
de nition. Abbreviated de nition: > Icacina oliviformis (Poir.) J.
Raynal 1975 & Mappia racemosa Jacq. 1797 & Pyrenacantha malvi-
folia Engl. 1893 ~ Oncotheca balansae Baill. 1891.
Etymology: Derived from Icacina (name of an included genus),
which refers to the resemblance of the type species, Icacina olivifor-
mis (Poir.) J. Raynal (= Icacina senegalensis A. Juss.), to Chrysobala-
nus icaco L. of Chrysobalanaceae ( Jussieu, 1823 ).
Reference phylogeny: is paper is the primary reference; see
Figs. 1, 2, and 4 . See also Kårehed (2001) , Bremer et al. (2002) ,
Angulo et al. (2013) , Byng et al. (2014) .
Composition: Alsodeiopsis , Casimirella , Cassinopsis , Desmo-
stachys , Hosiea , Icacina , Iodes , Lavigeria , Leretia , Mappia , Map-
pianthus , Merrilliodendron , Miquelia , Natsiatopsis , Natsiatum ,
Nothapodytes , Phytocrene , Pleurisanthes , Pyrenacantha , Rhyti-
caryum , Sarcostigma , Sleumeria , and Stachyanthus.
Diagnostic apomorphies: No non-DNA synapomorphies are
currently known.
Synonyms: None.
Comments: e name Icacinaceae was rst proposed by Miers
(1851) for ~13 genera formerly treated as the Icacineae tribe of
Olacaceae. Others (e.g., Engler, 1893 ; Bailey and Howard, 1941a ;
Sleumer, 1942 ) later applied the name Icacinaceae to a much larger
assemblage of genera (~54) and species (~400). Based on molecu-
lar-morphological phylogenetic analyses, Kårehed (2001) recog-
nized a much-reduced circumscription of Icacinaceae including
~34 genera and 200 species. None of the aforementioned circum-
scriptions were monophyletic. We apply the name Icacinaceae to a
clade of 23 genera. is represents the most-inclusive monophyetic
assemblage of genera from Icacinaceae s.l. including Icacina .
Because the position of Cassinopsis sister to the rest of
Icacina-
ceae
is not fully supported, we did not choose this species as an in-
ternal speci er. Instead we adopted a branch-modi ed node-based
de nition with three other species as internal speci ers, a ording
exibility to include/exclude Cassinopsis upon further analyses. If it
becomes sister to Oncotheca , for example, Icacinaceae (as de ned
above) would still exist; its composition would simply change
slightly, in that Cassinopsis would be excluded. is situation would
render Icacinaceae and Icacinoideae synonyms, with Icacinaceae
taking priority. e internal speci ers Mappia racemosa and
Icacina oliviformis (=the type of Icacina and thus ultimately Icaci-
naceae ) represent the two clades successively sister to the rest of the
family (a er Cassinopsis ). e third internal speci er, Pyrenacan-
tha malvifolia , occupies a highly nested position in the phylogeny.
Icacinoideae Engl. 1893: 242 [G. W. Stull], converted clade
name.
De nition: e least-inclusive clade containing Icacina olivifor-
mis (Poir.) J. Raynal 1975, Mappia racemosa Jacq. 1797, and Pyren-
acantha malvifolia Engl. 1893. is is a node-based de nition in
which all of the speci ers are extant. Abbreviated de nition: <
Icacina oliviformis (Poir.) J. Raynal 1975 & Mappia racemosa Jacq.
1797 & Pyrenacantha malvifolia Engl. 1893.
Etymology: Derived from Icacina (name of an included genus),
which refers to the resemblance of the type species, Icacina olivifor-
mis (Poir.) J. Raynal (= Icacina senegalensis A. Juss.), to Chrysobala-
nus icaco L. of Chrysobalanaceae ( Jussieu, 1823 ).
Reference phylogeny: is paper is the primary reference; see
Figs. 1–4 . See also Kårehed (2001) , Lens et al. (2008) , Angulo et al.
(2013) , and Byng et al. (2014) .
Composition: All genera of Icacinaceae except Cassinopsis .
Diagnostic apomorphies: Unilacunar nodes and simple perfora-
tion plates.
Synonyms: No formal synonyms exist, although several infor-
mally named groups constitute close approximations to Icacinoi-
deae : the Icacina group of Kårehed (2001) and group III of Bailey
and Howard (1941b) .
Comments: Engler (1893) used the name Icacinoideae for one of
three subfamilies of Icacinaceae, the other subfamilies being the
monogeneric Cardiopteridoideae and Lophopyxidoideae. Engler
(1893) recognized 36 genera in Icacinoideae, which he divided
among four tribes: Icacineae, Iodeae, Phytocreneae, and Sarcostig-
mateae. Subsequently, the circumscription of Icacinoideae was ex-
panded to include >50 genera, while Cardiopteris Wall. ex Royle
(Cardiopteridoideae) and Lophopyxis Hook.f. (Lophopyxidoideae)
were recognized as dubious members of Icacinaceae ( Sleumer,
1942 ; Bailey and Howard, 1941a ). e above circumscriptions of
Icacinoideae were shown to be polyphyletic by numerous phyloge-
netic studies ( Savolainen et al., 2000a , b ; Soltis et al., 2000 ; Kårehed,
2001 ).
We apply the name Icacinoideae to a clade comprising 22 gen-
era. No formal name with a closer correspondence to this clade ex-
ists in the literature. Icacinoideae as here circumscribed includes 11
16 A M E R I C A N J O U R N A L O F B O T A N Y
genera from the traditional Icacineae tribe and all genera of the tra-
ditional Iodeae, Phytocreneae, and Sarcostigmateae tribes, plus the
newly described genus Sleumeria ( Utteridge et al., 2005 ). All the
genera comprising Icacinoideae were included in our analyses
except Sleumeria a n d Natsiatopsis . However, Byng et al. (2014)
confirmed the placement of Sleumeria in this clade based on
phylogenetic analyses of the plastid loci matK , ndhF , and rbcL (al-
though Sleumeria was only represented by ndhF in the analyses),
and multiple lines of morphological evidence (mentioned in this
paper) suggest that Natsiatopsis falls within this clade close to Nat-
siatum . Icacinoideae corresponds closely to several informal group-
ings suggested in earlier studies—i.e., the Icacina group of Kårehed
(2001) and group III of Bailey and Howard (1941b) . e internal
speci ers Mappia racemosa and Icacina oliviformis represent the
two clades successively sister to the rest of Icacinoideae . e third
internal speci er, Pyrenacantha malvifolia , occupies a highly nested
position in the phylogeny. is clade is diagnosed by unilacunar
nodes and vessels with simple perforation plates. Cassinopsis , which
is sister to Icacinoideae , is distinguished by having trilacunar nodes
and vessels with sclariform perforation plates.
Metteniusaceae H. Karst. ex Schnizl. 1860: 142 [G. W. Stull],
converted clade name.
De nition: e least-inclusive clade containing Apodytes dimid-
iata E. Mey. ex Arn. 1840, Metteniusa edulis H. Karst. 1860, and
Platea parvi ora A. O. Dahl 1952. is is a node-based de nition
in which all of the specifiers are extant. Abbreviated definition:
< Apodytes dimidiata E. Mey. ex Arn. 1840 & Metteniusa edulis
H. Karst. 1860 & Platea parvi ora A. O. Dahl 1952.
Etymology: Derived from Metteniusa (name of an included ge-
nus), established by Hermann Karsten in honor of German bota-
nist Georg Heinrich Mettenius.
Reference phylogeny: is paper is the primary reference; see
Figs. 1, 2, and 4 .
Composition: Apodytes ,
Calatola , Dendrobangia , Emmotum ,
Metteniusa , Oecopetalum , Ottoschulzia , Pittosporopsis , Platea , Po-
raqueiba , and Rhaphiostylis.
Diagnostic apomorphies: No non-DNA synapomorphies are
currently known.
Synonyms: None.
Comments: Metteniusa has generally been treated as the sole
constituent of its own family, Metteniusaceae . González et al. (2007)
showed that Metteniusa represents a basal lamiid lineage, but their
sampling was too skeletal to place the genus precisely among the
basal lamiids. Phylogenetic analyses by Byng et al. (2014) suggested
that Metteniusa is closely related to several genera of the Emmotum
group of Icacinaceae sensu Kårehed (2001) : Emmotum , Ottoschul-
zia , Oecopetalum , and Poraqueiba . Our results are consistent with
Byng et al. (2014) in that Metteniusa is nested in the Emmotum
group and further show that this clade is related to multiple addi-
tional genera of Icacinaceae s.l.: Apodytes , Calatola , Dendrobangia ,
Platea , and Rhaphiostylis . e name Metteniusaceae was selected
for this clade (comprising 11 genera) because it is the oldest family
name associated with this clade’s constituent genera. Morpho-
logical synapomorphies of this clade are currently unknown.
e internal specifers used in this de nition were all included in
our phylogenetic analyses, except Metteniusa edulis , the type of
Metteniusa . Since the clade name Metteniusaceae is based on the
genus name Metteniusa , the type of the genus must be included in
the de nition ( Cantino et al., 2007 ). e monophyly of Metteniusa is
supported by numerous morphological features ( Lozano-Contreras
and de Lozano, 1988 ), suggesting that Metteniusa edulis is likely
closely related to Metteniusa tessmanniana , which was included in
our analyses.
Plateoideae G. W. Stull, new clade name.
De nition:
e least-inclusive clade including Calatola mollis
Standl. 1923 and Platea latifolia
Blume 1826. is is a node-based
de nition in which all of the speci ers are extant. Abbreviated
de nition: < Calatola mollis Standl. 1923 & Platea latifolia Blume
1826.
Etymology: Derived from the included genus Platea Blume.
Reference phylogeny: is paper is the primary reference; see
Figs. 1, 2, and 4 . See also Kårehed (2001) and Byng et al. (2014) .
Composition: Calatola and Platea.
Diagnostic apomorphies: Possible synapomorphies for this
clade include unisexual owers and indeterminate in orescences.
Synonymy: None.
Comments: Kårehed (2001) recovered a sister relationship be-
tween Calatola and Platea based on morphological phylogenetic
analyses. Based on three plastid loci, Byng et al. (2014) also recov-
ered this relationship with moderate support. e results in this
paper corroborate these earlier analyses with strong support. Cala-
tola mollis and Platea latifolia were selected as internal speci ers
because the former was included in our phylogenetic analyses and
the latter represents the type of Platea , the basis of the name
Plateoideae .
Apodytoideae G. W. Stull, new clade name.
De nition: e least-inclusive clade including Apodytes dimidi-
ata E. Mey. ex Arn. 1840, Dendrobangia boliviana Rusby 1896, and
Rhaphiostylis ferruginea Engl. 1909. is is a node-based de nition
in which all of the speci ers are extant. Abbreviated de nition: <
Apodytes dimidiata E. Mey. ex Arn. 1840 & Dendrobangia bolivi-
ana Rusby 1896 & Rhaphiostylis ferruginea Engl. 1909.
Etymology: Derived from the included genus Apodytes E. Mey.
ex Arn.
Reference phylogeny: is paper is the primary reference; see
Figs. 1, 2, and 4 . See also Kårehed (2001) and Byng et al. (2014) .
Composition: Apodytes , Dendrobangia , and Rhaphiostylis.
Diagnostic apomorphies: No non-DNA synapomorphies are
currently known.
Synonymy: None.
Comments: Several studies ( Kårehed, 2001 ; Lens et al., 2008 )
have recovered a sister relationship between Apodytes and Rhaphio-
stylis , b u t t h e s e a n a l y s e s d i d n o t i n c l u d e t h e N e o t r o p i c a l g e n u s Den-
drobangia . Byng et al. (2014) recovered Dendrobangia as sister to
Apodytes + Rhaphiostylis with weak Bayesian support. Our analyses
recovered Apodytes sister to Dendrobangia + Rhaphiostylis with
strong ML and Bayesian support. Although our results di er from
those of Byng et al. (2014) in the placement of Dendrobangia , both
indicate that these three genera form a clade. Morphological syn-
apomorphies for this clade are not currently known. e internal
speci ers selected were included in our phylogenetic analyses. Apo-
dytes dimidiata and Dendrobangia boliviana also constitute the
type species of their respective genera.
Metteniusoideae G. W. Stull, new clade name.
De nition: e least-inclusive clade including Emmotum fagifo-
lium Desv. ex Ham. 1825 and Metteniusa edulis H. Karst. 1860.
N O V E M B E R 2015 , VOLUME 102 STULL ET AL. RESOLVING BASAL LAMIID PHYLOGENY 17
Abbreviated de nition: < Emmotum fagifolium Desv. ex Ham. 1825
& Metteniusa edulis H. Karst. 1860.
Etymology: Derived from Metteniusa (name of an included ge-
nus), established by Hermann Karsten in honor of German bota-
nist Georg Heinrich Mettenius.
Reference phylogeny: is paper is the primary reference; see
Figs. 1, 2, and 4 . See also Duno de Stefano and Fernández-Concha
(2011) and Byng et al. (2014) .
Composition: Emmotum, Metteniusa, Oecopetalum, Ottoschul-
zia, Pittosporopsis, and Poraqueiba.
Diagnostic apomorphies: Possible synapomorphies for this
clade include stamen connectives extending beyond the anther
sacs, eshy petals, and fruits with persistent styles.
Synonymy: None.
Comments: In his combined molecular-morphological analy-
ses, Kårehed (2001) recovered relationships among Emmotum ,
Oecopetalum , Ottoschulzia , and Poraqueiba , which he informally
called the Emmotum group. Kårehed’s (2001) analyses, however,
did not include Pittosporopsis or Metteniusa . A recent paper by
Byng et al. (2014) found moderate support for a clade including the
Emmotum group plus Metteniusa , but Pittosporopsis was not in-
cluded in their analyses. Our analyses corroborate this general re-
sult and further show, with strong support, that Pittosporopsis
belongs in this clade.
e internal speci er Emmotum fagifolium represents the type
of the genus Emmotum . Although we did not include this species in
our phylogenetic analyses—instead, we included Emmotum nitens
(Benth.) Miers—a morphology-based phylogeny of the genus
( Duno de Stefano and Fernández-Concha, 2011 ) found numerous
morphological synapomorphies supporting its monophyly. e
other internal speci er, Metteniusa edulis , represents the type of
Metteniusa , the monophyly of which is supported by numerous
morphological features ( Lozano-Contreras and de Lozano, 1988 ).
Recommendations for APG W e s y n t h e s i z e d o u r r e s u l t s w i t h p r e v i -
ous studies (e.g., Kårehed, 2001 ; Lens et al., 2008 ; Byng et al., 2014 ) to
provide a familial and ordinal classi cation of genera formerly in-
cluded in Icacinaceae s.l. ( Table 2 ). We recommend that the next edi-
tion of APG adopt this classi cation. Compared with the most recent
APG system ( APG III, 2009 ), this classi cation includes a reduced
circumscription of Icacinaceae (23 genera), an expanded circum-
scription of Metteniusaceae (11 genera), and the recognition of two
orders new to APG: Icacinales Tiegh. ex Reveal (including Icaci-
naceae and Oncothecaceae) and Metteniusales Takht. (including
Metteniusaceae). Garryales Lindl. should be restricted to the families
Eucommiaceae Engl. and Garryaceae Lindl. ese changes are based
largely on the results from this paper, and in all cases they are strongly
supported by both ML bootstrap and Bayesian posterior probability
values ( Fig. 1 ). Although recognizing Metteniusales to include a
single family is taxonomically redundant, it is necessary under a rank-
based system given the isolated phylogenetic position of Metteniusa-
ceae; were Metteniusaceae included in any other order, it would
render that order nonmonophyletic.
ACKNOWLEDGEMENTS
G.W.S. thanks S. R. Manchester for his invaluable support and
assistance throughout the execution of this project. e authors
thank A. Liston, R. G. Olmstead, P. F. Stevens, and an anonymous
reviewer for helpful suggestions that improved the manuscript and
W. S. Judd for assistance with PhyloCode names. K. Perkins, J.
Solomon, J. J. Wieringa, and G. ijsse kindly facilitated sampling
of herbarium material for DNA sequencing from FLAS, MO, WAG,
and L, respectively. e authors thank M. Deyholos and J. Leebens-
Mack for contributing multiple 1KP samples used in this paper,
Z. K. Zhou and his students for help with eldwork in China,
M. J. Moore for providing unpublished data and advice on plastome
assembly, M. A. Gitzendanner for assistance with library construc-
tion and data processing, and A. A. Crowl for help with analyses.
is work was supported by NSF grant DEB-1310805 (Doctoral
Dissertation Improvement Grant to S. R. Manchester, P.S.S., and
G.W.S.), NSF grant DEB-0743457 (to P. Jørgensen), the American
Society of Plant Taxonomists, the Society of Systematic Biologists,
the Botanical Society of America, the Explorers Club, and the
Torrey Botanical Society.
LITERATURE CITED
Airy Shaw , H. K. 1965 . Diagnoses of new families, new names, etc. for the sev-
enth edition of Willis’s Dictionary . Kew Bulletin 18 : 249 273 .
Albach , D. C. , P. S. Soltis , D. E. Soltis , and R. G. Olmstead . 2001 . Phylogenetic
analysis of asterids based on sequences of four genes. Annals of the Missouri
Botanical Garden 88 : 163 212 .
Angulo , D. F. , R. Duno de Stefano , and G. W. Stull . 2013 . Systematics of
Mappia (Icacinaceae), an endemic genus of tropical America. Phytotaxa
116 : 1 18 .
APG [Angiosperm Phylogeny Group] . 1998 . An ordinal classi cation for the
families of the owering plants. Annals of the Missouri Botanical Garden
85 : 531 553 .
APG II [Angiosperm Phylogeny Group II] . 2003 . An update of the Angiosperm
Phylogeny Group classi cation for the orders and families of owering
plants: APG II. Botanical Journal of the Linnean Society 141 : 399 436 .
APG III [Angiosperm Phylogeny Group III] . 2009 . An update of the
Angiosperm Phylogeny Group classi cation for the orders and families
of owering plants: APG III. Botanical Journal of the Linnean Society 161 :
105 121 .
Bailey , I. W. , and R. A. Howard . 1941a . e comparative morphology of the
Icacinaceae I. Anatomy of the node and internode. Journal of the Arnold
Arboretum 22 : 125 132 .
Bailey , I. W. , and R. A. Howard . 1941b . e comparative morphology of the
Icacinaceae II. Vessels. Journal of the Arnold Arboretum 22 : 171 187 .
Bailey , I. W. , and R. A. Howard . 1941c . e comparative morphology of the
Icacinaceae III. Imperforate tracheary elements and xylem parenchyma.
Journal of the Arnold Arboretum 22 : 432 442 .
Bailey , I. W. , and R. A. Howard . 1941d . e comparative morphology of
the Icacinaceae IV. Rays and the secondary xylem. Journal of the Arnold
Arboretum 22 : 556 568 .
Baillon , H. E. 1891 . Sur le nouveau genre Oncotheca. Bulletin Mensuel de la
Société Linnéenne de Paris 2 : 931 932 .
Baillon , H. E. 1892 . Histoire des plantes, vol. 11. Hachette, Paris, France.
Bentham , G. 1841 . Account of two new genera allied to Olacineae. Transactions
of the Linnean Society of London 18 : 671 685 .
Bentham , G. 1862 . Olacineae . In G. Bentham and J. D. Hooker [eds.], Genera
plantarum, vol. I, part 1, 342–355. Lovell Reeve, London, UK.
Bremer , B. , K. Bremer , N. Heidari , P. Erixon , R. G. Olmstead , A. A. Anderberg ,
M. KällersjÖ , and E. Barkhordarian . 2002 . Phylogenetics of asterids based
on 3 coding and 3 non-coding chloroplast DNA markers and the utility of
non-coding DNA at higher taxonomic levels. Molecular Phylogenetics and
Evolution 24 : 274 301 .
Bremer , K. , E. M. Friis , and B. Bremer . 2004 . Molecular phylogenetic dating of
asterid owering plants shows early Cretaceous diversi cation. Systematic
Biology 53 : 496 505 .
Burge , D. O. 2011 . Molecular phylogenetics of Garrya (Garryaceae). Madrono
58 : 249 255 .
18 A M E R I C A N J O U R N A L O F B O T A N Y
Byng , J. W. , B. Bernardini , J. A. Joseph , M. W. Chase , and T. M. A. Utteridge .
2014 . Phylogenetic relationships of Icacianceae focusing on the vining
genera. Botanical Journal of the Linnean Society 176 : 277 294 .
Cameron , K. M. 2003 . On the phylogenetic position of the New Caledonian
endemic families Paracryphiaceae, Oncothecaceae, and Strasburgeriaceae:
A comparison of molecules and morphology. Botanical Review 68 : 428 443 .
C a n t i n o , P . D . , a n d K . d e Q u e i r o z . 2 0 1 0 . I n t e r n a t i o n a l c o d e o f p h y l o g e n e t i c n o -
menclature. Website http://www.ohio.edu/phylocode/ [accessed 22 June 2015].
Cantino , P. D. , J. A. Doyle , S. W. Graham , W. S. Judd , R. G. Olmstead , D. E.
Soltis , P. S. Soltis , and M. J. Donoghue . 2007 . Towards a phylogenetic no-
menclature of Tracheophyta. Taxon 56 : 822 846 .
Carpenter , C. S. , and W. C. Dickison . 1976 . e morphology and relationships
of Oncotheca balansae. Botanical Gazette 137 : 141 153 .
Chase , M. W. , D. E. Soltis , R. G. Olmstead , D. H. Les , B. D. Mishler , M. R.
Duvall , R. A. Price , et al. 1993 . Phylogenetics of seed plants: an analysis of
nucleotide sequencings from the plastid gene rbcL. Annals of the Missouri
Botanical Garden 80 : 528 581 .
Cronquist , A. 1981 . An integrated system of classi cation of owering plants.
Columbia University Press, New York, New York, USA.
Cummings , M. P. , S. A. Handley , D. S. Myers , D. L. Reed , A. Rokas , and K.
Winka . 2003 . Comparing bootstrap and posterior probability values in the
four-taxon case. Systematic Biology 52 : 477 487 .
Dahl , O. 1952 . e comparative morphology of the Icacinaceae, VI. e pollen.
Journal of the Arnold Arboretum 33 : 252 286 .
d e C a n d o l l e , A . P . 1 8 2 4 . O l a c i n e a e . In A . P . d e C a n d o l l e [ e d . ] , P r o d r u m u s s y s t e m a -
tis naturalis regni vegetabilis, vol. I, 531–534. Treuttel et Würtz, Paris, France.
Dickison , W. C. 1986 . Further observations on the oral anatomy and pollen
morphology of Oncotheca (Oncothecaceae). Brittonia 38 : 249 259 .
Doyle , J. J. 1992 . Gene trees and species trees: Molecular systematics as one-
character taxonomy. Systematic Biology 17 : 144 163 .
Doyle , J. J. , and J. L. Doyle . 1987 . A rapid DNA isolation procedure for small
quantities of fresh leaf tissue. Phytochemistry Bulletin 19 : 11 15 .
Duno de Stefano , R. , D. F. Angulo , and F. W. Stau er . 2007 . Emmotum harleyi ,
a new species from Bahia, Brazil, and lectotypi cation of other Icacinaceae.
Novon 17 : 306 309 .
Duno de Stefano , R. , and G. C. Fernández-Concha . 2011 . Morphology-inferred
phylogeny and a revision of the genus Emmotum (Icacinaceae). Annals of
the Missouri Botanical Garden 98 : 1 27 .
Endress , P. K. , and A. Rapini . 2014 . Floral structure of Emmotum (Icacinaceae
sensu stricto or Emmotaceae), a phylogenetically isolated genus of lamiids
with a unique pseudotrimerous gynoecium, bitegmic ovules and monospo-
rangiate thecae. Annals of Botany 114 : 945 959 .
Engler , A. 1893 . Icacinaceae . In A. Engler and K. Prantl [eds.], 1896. Die
natürlichen P anzenfamilien, vol. III, 5, 233–257. Wilhelm Engelmann,
Leipzig, Germany.
Erbar , C. , and P. Leins . 1996 . Distribution of the character states “early sym-
petaly” and “late sympetaly” within the “Sympetalae Tetracyclicae” and pre-
sumably allied groups. Botanica Acta 109 : 427 440 .
Erixon , P. , B. Svennblad , T. Britton , and B. Oxelman . 2003 . Reliability of
Bayesian posterior probabilities and bootstrap frequencies in phylogenetics.
Systematic Biology 52 : 665 673 .
González , F. A. , J. Betancur , O. Maurin , J. V. Freudenstein , and M. W. Chase .
2007 . Metteniusaceae, an early-diverging family in the lamiid clade. Taxon
56 : 795 800 .
González , F. A. , and P. J. Rudall . 2010 . Flower and fruit characters in the early-
divergent lamiid family Metteniusaceae, with particular reference to the
evolution of pseudomonomery. American Journal of Botany 97 : 191 206 .
Guillaumin , A. 1938 . Observations morphologiques et anatomiques sur le
genre Oncotheca . Revue Générale de Botanique 50 : 629 635 .
Guillaumin , A. 1948 . Flore analytique et synoptique de la Nouvelle-Calédonie
(Phanérogames). O ce de la Recherche Scienti que Coloniale, Paris, France.
Howard , R. A. 1940 . Studies of the Icacinaceae. I. Preliminary taxonomic
notes. Journal of the Arnold Arboretum 21 : 461 489 .
Howard , R. A. 1942a . Studies of the Icacinaceae. II. Humirianthera, Leretia,
Mappia, and Nothapodytes , valid genera of the Icacineae. Journal of the
Arnold Arboretum 23 : 55 78 .
Howard , R. A. 1942b . Studies of the Icacinaceae. III. A revision of Emmotum.
Journal of the Arnold Arboretum 23 : 479 494 .
Howard , R. A. 1942c . Studies of the Icacinaceae. IV. Considerations of the
New World genera. Contributions from the Gray Herbarium of Harvard
University 142 : 3 60 .
Howard , R. A. 1942d . Studies of the Icacinaceae. V. A revision of the genus
Citronella D. Don. Contributions from the Gray Herbarium of Harvard
University 142 : 60 89 .
Howard , R. A. 1943a . Studies of the Icacinaceae. VI. Irvingbaileya and
Codiocarpus , two new genera of the Icacineae. Brittonia 5 : 47 57 .
Howard , R. A. 1943b . Studies of the Icacinaceae. VII. A revision of the genus
Medusanthera Seeman. Lloydia 6 : 133 143 .
Howard , R. A. 1943c . Studies of the Icacinaceae. VIII. Brief notes of some Old
World genera. Lloydia 6 : 144 154 .
Howard , R. A. 1992 . A revision of Casimirella , including Humirianthera
(Icacinaceae). Brittonia 44 : 166 172 .
Hua , P. , and R. A. Howard . 2008 . Icacinaceae . In Z. Y. Wu, P. H. Raven, and
D. Y. Hong [eds.], Flora of China, vol. 11, 505–514. Science Press, Beijing,
and Missouri Botanical Garden Press, St. Louis, Missouri, USA.
Huelsenbeck , J. P. , and F. R. Ronquist . 2001 . MrBayes: Bayesian inference of
phylogeny. Biometrics 17 : 754 755 .
Hunter , S. S. , R. T. Lyon , B. A. J. Sarver , K. Hardwick , L. J. Forney , M. L. Settles .
2015 . Assembly by Reduced Complexity (ARC): A hybrid approach for tar-
geted assembly of homologous sequences. bioRxiv .
Hutchinson , J. , and J. M. Dalziel . 1958 . Icacinaceae . In R. W. J. Keay [ed.],
Flora of west tropical Africa, 2nd ed., vol. 1, 636–644. Crown Agents for
Overseas Governments and Administrations, London, UK.
Jansen , R. K. , Z. Cai , L. A. Raubeson , H. Daniell , C. W. dePamphilis , J. Leebens-
Mack , K. F. Müller , et al. 2007 . Analysis of 81 genes from 64 plastid ge-
nomes resolves relationships in angiosperms and identi es genome-scale
evolutionary patterns. Proceedings of the National Academy of Sciences, USA
104 : 19369 19374 .
Jian , S. , P. S. Soltis , M. A. Gitzendanner , M. J. Moore , R. Li , T. A. Hendry ,
Y. L. Qui , et al. 2008 . Resolving an ancient, rapid radiation in Saxifragales.
Systematic Biology 57 : 38 57 .
Joshi , N. A. , and J. N. Fass . 2011 . Sickle: A sliding-window, adaptive, quality-
based trimming tool for FastQ les (Version 1.33) [so ware]. Available at
https://github.com/najoshi/sickle .
Judd , W. S. , C. S. Campbell , E. A. Kellogg , P. F. Stevens , and M. J. Donoghue .
2008 . Plant systematics: A phylogenetic approach, 3rd ed. Sinauer,
Sunderland, Massachusetts, USA.
Judd , W. S. , and R. G. Olmstead . 2004 . A survey of tricolpate (eudicot) phylo-
genetic relationships. American Journal of Botany 91 : 1627 1644 .
Jussieu , A. H. L. 1823 . Description d’un genre nouveae nommé Icacina .
Mémoires de la Société d’Histoire Naturelle de Paris 1 : 174 178 .
Kårehed , J. 2001 . Multiple origins of the tropical forest tree family Icacinaceae.
American Journal of Botany 88 : 2259 2274 .
Karsten , H. 1860 . Metteniusa edulis Karst . In H. Karsten, Florae colombiae,
vol. I, part 2, 79–80. Ferdinandi Duemmleri successores, Berlin, Germany.
Katoh , K. , and D. M. Standley . 2013 . MAFFT multiple sequence alignment
so ware version 7: improvements in performance and usability. Molecular
Biology and Evolution 30 : 772 780 .
Lens , F. , J. Kårehed , P. Baas , S. Jansen , D. Rabaey , S. Huysmans , T. Hamann ,
and E. Smets . 2008 . e wood anatomy of the polyphyletic Icacinaceae s.l.,
and their relationships within asterids. Taxon 57 : 525 552 .
Lobreau-Callen , D. 1972 . Pollen des Icacinaceae. I. Atlas. Pollen et Spores 14 :
345 388 .
Lobreau-Callen , D. 1973 . Le pollen des Icacinaceae: II. Observations en
microscopie électronique, corrélations, conclusions. Pollen et Spores 15 :
47 89 .
Lozano-Contreras , G. , and N. B. de Lozano . 1988 . Metteniusaceae . In P. Pinto
and G. Lozano [eds.], Flora de Colombia, vol. 11. Universidad Nacional de
Colombia, Bogotá, Colombia.
Lucas , G. 1968 . Icacinaceae . In E. Milne-Redhead and R. M. Polhill [eds.],
Flora of tropical East Africa. Crown Agents for Overseas Government,
London, UK.
N O V E M B E R 2015 , VOLUME 102 STULL ET AL. RESOLVING BASAL LAMIID PHYLOGENY 19
McNeill , J. , F. R. Barrie , W. R. Buck , V. Demoulin , W. Greuter , D. L. Hawksworth ,
P. S. Herendeen , et al. [eds.] 2012 . International Code of Nomenclature for
algae, fungi and plants (Melbourne code). Regnum vegetabile 154. Koeltz
Scienti c Books, Koenigstein, Germany.
McPherson , G. , P. Morat , and J. M. Veillon . 1981 . Existence d’une deux-
ième espèce appartenant au genre Oncotheca endémique de la Nouvelle-
Calédonie et nouvelles données concernant les Oncothécacées . Bulletin du
Muséum National d'Histoire Naturelle (Paris), ser. 4, misc. 3 : 305 311 .
Miers , J. 1851 . Observations on the a nities of the Olacaceae . Annals and
Magazine of Natural History , second series 8 : 11 184 .
Miers , J. 1852 . Observations on the a nities of the Icacinaceae . Annals and
Magazine of Natural History , second series 9 : 218 226 .
Miers , J. 1864 . On the genus Villaresia , with a description of a new species. Le
Journal de Botanique 11 : 257 266 .
Moore , M. J. , C. D. Bell , P. S. Soltis , and D. E. Soltis . 2007 . Using plastid
genome-scale data to resolve enigmatic relationships among basal an-
giosperms. Proceedings of the National Academy of Sciences, USA 104 :
19363 19368 .
Moore , M. J. , P. S. Soltis , C. D. Bell , J. G. Burleigh , and D. E. Soltis . 2010 .
Phylogenetic analysis of 83 plastid genes further resolves the early diversi-
cation of eudicots. Proceedings of the National Academy of Sciences, USA
107 : 4623 4628 .
Olmstead , R. G. , B. Bremer , K. Scott , and J. D. Palmer . 1993 . A parsimony
analysis of the Asteridae sensu lato based on rbcL sequences. Annals of the
Missouri Botanical Garden 80 : 700 722 .
Olmstead , R. G. , K.-J. Kim , R. K. Jansen , and S. J. Wagsta . 2000 . e phylog-
eny of the Asteridae sensu lato based on chloroplast ndhF gene sequences.
Molecular Phylogenetics and Evolution 16 : 96 112 .
Olmstead , R. G. , H. J. Michaels , K. M. Scott , and J. D. Palmer . 1992 .
Monophyly of the Asteridae and identi cation of their major lineages
inferred from DNA sequences of rbcL. Annals of the Missouri Botanical
Garden 79 : 249 265 .
Olmstead , R. G. , P. A. Reeves , and A. C. Yen . 1998 . Patterns of sequence evolu-
tion and implications for parsimony analysis of chloroplast DNA. In D. E.
Soltis, P. S. Soltis, and J. J. Doyle [eds.], Molecular systematics of plants II:
DNA sequencing, 164–187. Klumer, Norwell, Massachusetts.
Olmstead , R. G. , and J. A. Sweere . 1994 . Combining data in phylogenetic
systematics: An empirical approach using three molecular data sets in the
Solanaceae. Systematic Biology 43 : 467 481 .
Qiu , Y.-L. , L. Li , B. Wang , J.-Y. Xue , T. A. Hendry , R.-Q. Li , J. W. Brown , et al.
2010 . Angiosperm phylogeny inferred from sequences of four mitochon-
drial genes. Journal of Systematics and Evolution 48 : 391 425 .
Rambaut , A. , and A. J. Drummond . 2009 . Tracer, version 1.5 for Macintosh.
Computer program and documentation distributed by the author, website
http://beast.bio.ed.ac.uk/Tracer .
Refulio-Rodriguez , N. F. , and R. G. Olmstead . 2014 . Phylogeny of Lamiidae.
American Journal of Botany 101 : 287 299 .
Reveal , J. L. 1993 . New ordinal names for extant vascular plants . Phytologia
74 : 173 177 .
Ronquist , F. , M. Teslenko , P. van der Mark , D. Ayres , A. Darling , S. Höhna ,
B. Larget , et al. 2012 . MrBayes 3.2: E cient Bayesian phylogenetic infer-
ence and model choice across a large model space. Systematic Biology 61 :
539 542 .
Ruhfel , B. R. , M. A. Gitzendanner , P. S. Soltis , D. E. Soltis , and J. G. Burleigh .
2014 . From algae to angiosperms—Inferring the phylogeny of green plants
(Viridiplantae) from 360 plastid genomes. BMC Evolutionary Biology 14 : 23 .
Savolainen , V. , M. W. Chase , S. B. Hoot , C. M. Morton , D. E. Soltis , C. Bayer ,
M. F. Fay , et al. 2000a . Phylogenetics of owering plants based upon a com-
bined analysis of plastid atpB and rbcL gene sequences. Systematic Biology
49 : 306 362 .
Savolainen , V. , M. F. Fay , D. C. Albach , A. Backlund , M. van der Bank , K. M.
Cameron , S. A. Johnson , et al. 2000b . Phylogeny of the eudicots: A nearly
complete familial analysis based on rbcL gene sequences. Kew Bulletin 55 :
257 309 .
Sleumer , H. 1934 . Eine neue Art der Gattung Aveledoa Pittier. Notizblatt des
Botanischen Gartens und Museums zu Berlin-Dahlem 12 : 148 150 .
Sleumer , H. 1936 . Über die Gattung Metteniusa Karsten (= Aveledoa Pittier).
Notizblatt des K öniglichen Botanischen Gartens und Museums Berlin-
Dahlem 13 : 359 361 .
Sleumer , H. 1942 . Icacinaceae . In A. Engler [ed.], Die natürlichen
P anzenfamilien, 2nd ed., vol. 20b, 322–396. Wilhelm Engelmann, Leipzig,
Germany.
Sleumer , H. 1969 . Materials towards the knowledge of the Icacinaceae of Asia,
Malesia, and adjacent areas. Blumea 17 : 181 264 .
Sleumer , H. 1971 . Icacinaceae . In C. G. G. J. van Steenis [ed.], Flora Malesiana,
series I, vol. 7, 1–87. Noordho , Leyden, Netherlands.
Soltis , D. E. , S. A. Smith , N. Cellinese , K. J. Wurdack , D. C. Tank , S. F.
Brockington , N. F. Refulio-Rodriguez , et al. 2011 . Angiosperm phylogeny:
17 genes, 640 taxa. American Journal of Botany 98 : 704 730 .
Soltis , D. E. , and P. S. Soltis . 1998 . Choosing and approach and an appropri-
ate gene for phylogenetic analysis. In D. E. Soltis, P. S. Soltis, and J. J. Doyle
[eds.], Molecular systematics of plants II: DNA sequencing, 1–42. Klumer,
Norwell, Massachusetts.
Soltis , D. E. , P. S. Soltis , M. W. Chase , M. E. Mort , D. C. Albach , M. Zanis , V.
Savolainen , et al. 2000 . Angiosperm phylogeny inferred from 18S rDNA,
rbcL , and atpB sequences. Botanical Journal of the Linnean Society 133 :
381 461 .
Soltis , P. S. , and D. E. Soltis . 1998 . Molecular evolution of 18S ribosomal DNA
in angiosperms: Implications for character weighting in phylogenetic analy-
sis . In D. E. Soltis, P. S. Soltis, and J. J. Doyle [eds.], Molecular systematics
of plants II: DNA sequencing, 188–210. Klumer, Norwell, Massachusetts,
USA.
Soltis , P. S. , D. E. Soltis , and M. W. Chase . 1999a . Angiosperm phylogeny in-
ferred from multiple genes as a tool for comparative biology. Nature 402 :
402 404 .
Soltis , P. S. , D. E. Soltis , P. G. Wolf , D. L. Nickrent , S.-M. Chaw , and R. L.
Chapman . 1999b . Land plant phylogeny inferred from 18S rDNA se-
quences: Pushing the limits of rDNA sequences? Molecular Biology and
Evolution 16 : 1774 1784 .
Stamatakis , A. 2014 . RAxML version 8: A tool for phylogenetic analysis and
post-analysis of large phylogenies. Bioinformatics .
Stevens , P. F. 2001 onward . Angiosperm phylogeny website, version 12, July
2012 [more or less continuously updated]. Website http://www.mobot.org/
MOBOT/research/APweb/ [accessed 21 May 2015].
Stull , G. W. , F. Herrera , S. R. Manchester , C. Jaramillo , and B. H. Tiffney .
2012 . Fruits of an “Old World” tribe (Phytocreneae; Icacinaceae)
from the Paleogene of North and South America. Systematic Botany 37 :
784 794 .
Stull , G. W. , M. J. Moore , V. S. Mandala , N. A. Douglas , H.-R. Kates , X. Qi , S.
F. Brockington , et al. 2013 . A targeted enrichment strategy for massively
parallel sequencing of angiosperm plastid genomes. Applications in Plant
Sciences 1 : 1200497 .
Sun , M. , D. E. Soltis , P. S. Soltis , X. Zhu , J. G. Burleigh , and Z. Chen . 2015 . Deep
phylogenetic incongruence in the angiosperm clade Rosidae. Molecular
Phylogenetics and Evolution 83 : 156 166 .
Suzuki , Y. , G. V. Glazko , and M. Nei . 2002 . Overcredibility of molecular phy-
logenies obtained by Bayesian phylogenetics. Proceedings of the National
Academy of Sciences, USA 99 : 16138 16143 .
Takhtajan , A. 1969 . Flowering plants: Origin and dispersal. Smithsonian
Institution Press, Washington, D.C., USA.
Takhtajan , A. 1997 . Diversity and classi cation of owering plants. Columbia
University Press, New York, New York, USA.
Thorne , R. F. 2000 . The classification and geography of the flowering
plants: dicotyledons of the class Angiospermae . Botanical Review 66 :
441 647 .
Utteridge , T. M. A. , H. Nagasamu , S. P. Teo , L. C. White , and P. Gasson . 2005 .
Sleumeria (Icacinaceae): A new genus from northern Borneo. Systematic
Botany 30 : 635 643 .
van Staveren , M. G. C. , and P. Baas . 1973 . Epidermal leaf characters of the
Malesian Icacinaceae. Acta Botanica Neerlandica 22 : 329 359 .
van Tieghem , P. 1897 . Sur les Phanérogams sans graines, format la divisions
des Inseminées. Bulletin de la Société Botanique de France 44 : 99 139 .
20 A M E R I C A N J O U R N A L O F B O T A N Y
Villiers , J.-F. 1973 . Icacinaceae . In A. Aubréville and J.-F. Leroy [eds.], Flore de
Gabon, vol. 20, 3–100. Muséum National d’Histoire Naturelle, Paris, France.
Wang , H. , M. J. Moore , P. S. Soltis , C. D. Bell , S. F. Brockington , R. Alexandre , and
C. C. Davis . 2009 . Rosid radiation and the rapid rise of angiosperm-dominated
forests. Proceedings of the National Academy of Sciences, USA 106 : 3853 3858 .
Watson , L. , and M. J. Dallwitz . 1992 onward. e families of owering plants:
Descriptions, illustrations, identi cation, and information retrieval, version
19 August 2014. Website http://delta-intkey.com .
Whit eld , J. B. , and P. J. Lockhart . 2007 . Deciphering ancient rapid radiations.
Trends in Ecology & Evolution 22 : 258 265 .
Wickett , N. J. , S. Mirarab , N. Nguyen , T. Warnow , E. Carpenter , N. Matasci , S.
Ayyampalayam , et al. 2014 . A phylotranscriptomics analysis of the origin
and diversi cation of land plants. Proceedings of the National Academy of
Sciences, USA 111 : E4859 E4868 .
Wortley , A. H. , P. J. Rudall , D. J. Harris , and R. W. Scotland . 2005 . How much
data are needed to resolve a di cult phylogeny? Case study in Lamiales.
Systematic Biology 54 : 697 709 .
Wyman , S. K. , R. K. Jansen , and J. L. Boore . 2004 . Automatic annotation of
organellar genomes with DOGMA. Bioinformatics 20 : 3252 3255 .
Xi , Z. , L. Liu , J. S. Rest , and C. C. Davis . 2014 . Coalescent versus concatenation
methods and the placement of Amborella as sister to water lilies. Systematic
Biology 63 : 919 932 .
Xi , Z. , B. R. Ruhfel , H. Schaefer , A. M. Amorim , M. Sugumaran , K. J. Wurdack ,
P. K. Endress , et al. 2012 . Phylogenomics and a posteriori data partitioning
resolve the Cretaceous angiosperm radiation Malpighiales. Proceedings of
the National Academy of Sciences, USA 109 : 17519 17524 .
Zerbino , D. R. , and E. Birney . 2008 . Velvet: Algorithms for de novo short read
assembly using de Bruijn graphs. Genome Research 18 : 821 829 .
... Historically, this genus was placed into either Cornaceae (Harms, 1898;Wangerin, 1910;Hutchinson, 1967;Cronquist, 1988) or the monotypic family Aucubaceae (Willis and Shaw, 1973;Takhtajan, 1980;Bremer et al., 1998). Recently, phylogenetic analyses based on chloroplast DNA sequences revealed a sister relationship between Aucuba and Garrya, and the two genera are in turn closely related to Eucommiaceae (Xiang et al., 1993;Xiang and Soltis, 1998;Soltis et al., 2000;Bremer et al., 2003;Stull et al., 2015). Since Aucuba and Garrya show high levels of similarity in their morphologies and chemical components, they were grouped in Garryaceae. ...
... Complete plastome sequences have been widely used for resolving recalcitrant relationships in phylogenetically challenging taxa (Jansen et al., 2007;Barrett et al., 2013;Stull et al., 2015). In this study, the phylogenetic placement of Aucuba was inferred by reconstructing phylogenetic relationships based on a large dataset comprising 68 plastid CDSs. ...
... Our data strongly support the sister relationship between E. ulmoides and Aucuba, as well as the monophyly of both Garryales and Garryaceae. This result is consistent with previous molecular phylogenetic analyses (Xiang et al., 1993;Xiang and Soltis, 1998;Soltis et al., 2000;Bremer et al., 2003;Stull et al., 2015), providing plastid phylogenomic evidence to accept the order Garryales as circumscribed by Bremer et al. (2003). ...
Article
Full-text available
Aucuba (Garryaceae), which includes approximately ten evergreen woody species, is a genus endemic to East Asia. Their striking morphological features give Aucuba species remarkable ornamental value. Owing to high levels of morphological divergence and plasticity, species definitions of Aucuba remain perplexing and problematic. Here, we sequenced and characterized the complete plastid genomes (plastomes) of three Aucuba species: Aucuba chlorascens , Aucuba eriobotryifolia , and Aucuba japonica . Incorporating Aucuba plastomes available in GenBank, a total of seven Aucuba plastomes, representing six out of ten species of Aucuba , were used for comparative plastome analysis, phylogenetic analysis and divergence time estimation in this study. Comparative analyses revealed that plastomes of Aucuba are highly conserved in size, structure, gene content, and organization, and exhibit high levels of sequence similarity. Phylogenetic reconstruction based on 68 plastid protein-coding genes strongly supported the monophyly of Garryales, Garryaceae and Aucuba. Aucuba eriobotryifolia was sister to the other Aucuba species examined, consistent with its unique fused anther locule. The divergence time of Aucuba was estimated to be approximately late Miocene. Extant Aucuba species derived from recent divergence events associated with the establishment of monsoonal climates in East Asia and climatic fluctuations.
... Recently, in a phylogenetic analysis based on 50 plastid genes, Stull et al. (2015) found that the Apodytes group, the Emmotum group, and Pittosporopsis of the Icacina group are more closely related to Metteniusa and moved these groups into Metteniusaceae in its own order, Metteniusales. The expanded Metteniusaceae comprise Metteniusa and 10 genera from Icacinaceae sensu Kårehed (2001) and were classified into three subfamilies: Plateoideae (Calatola Standl. ...
... was proposed by González et al. (2007), who recognized each genus as belonging to its own family. Metteniusaceae were treated as comprising these two genera, with the possible inclusion of Dendrobangia, in the most recent comprehensive treatment of morphological characteristics (Dickison and Bittrich, 2016), which was prepared before Stull et al. (2015) was published. Androecium and gynoecium characters are useful and important in the study of plant phylogeny and macroevolution (Endress 2011a). ...
Article
Full-text available
Pittosporopsis Craib, previously considered a member of the Icacinaceae sensu lato (s.l.), was transferred recently to the expanded Metteniusaceae, a family of 11 genera that needs morphological reevaluation to assess possible synapomorphies given its new circumscription. We investigated the anther and ovule developmental characters of Pittosporopsis and compared them with those of other members of Metteniusaceae as well as Icacinaceae s.l. to the extent possible. These characters are important to establish morphological synapomorphies of Metteniusaceae and to provide insights into embryology of the early diverging clades of core asterids. Within the family, Pittosporopsis shares several uncommon embryological characters with both Metteniusa H. Karst. and Emmotum Ham., such as a connective with numerous tanniferous cells and two superposed ovules within one locule. The ovule of Pittosporopsis is bitegmic, the third report of this condition (after Emmotum and Quintinia Baker f.) in the recently recircumscribed campanulids. Characters not shared with other members of Metteniusaceae include an unusual outward protuberance in the anther wall derived from the division and enlargement of endothecial cells, and a hypostase connecting the embryo sac and the ovular vascular bundle. Interestingly, a hypostase is known from Bruniaceae, which is sister to the core campanulids. Although further studies are needed to fully characterize the embryology and floral development of Pittosporopsis and the other genera now placed in Metteniusaceae, our study provides new insights into the embryology of the first diverging campanulid clades.
... Previously, the cachichín was considered within the Icacinaceae family (Kårehed, 2001;Stull, Duno de Stéfano, Soltis, & Soltis, 2015), although recent phylogenetic studies have placed it within the Metteniusaceae family, which consists of 11 genders and at least 59 species, that are mainly distributed in tropical areas around the world (Hernández-Urban et al., 2019). In addition to the edible seed, some species of this family produce raw materials for the textile industry, fuelwood and wood. ...
... Anteriormente el cachichín fue considerado dentro de la familia Icacinaceae (Kårehed, 2001;Stull, Duno de Stéfano, Soltis, & Soltis, 2015), aunque estudios filogenéticos recientes le han ubicado dentro de la familia Metteniusaceae, la cual está integrada por 11 géneros y por lo menos 59 especies, que se distribuyen principalmente en las regiones tropicales alrededor del mundo (Hernández-Urban et al., 2019). Además de la semilla comestible, algunas de las especies de esta familia producen materias primas para la industria textil, leña y madera. ...
Article
Full-text available
The cachichín (Oecopetalum mexicanum Greenm. & C.H. Thomps.) is an arboreal species that produces an edible seed to which nutraceutical properties have been attributed to improve human health. The objective of this study was to review the most relevant aspects of scientific research on the cultivation, nutritional properties and pharmacological potential of this seed. Diverse literary sources and databases that to date have been integrated on the cachichín, were identified. The cachichín is a plant species native from Mexico and belongs to the family Metteniusaceae. Most of the edible seed and wood are produced in the municipality of Misantla, Veracruz, Mexico. In average values, the composition of the seed is proteins 12.59 %, carbohydrates 41.61 %, lipids 39.25 %, fiber 4.25 % and ashes 2.30 %. Within its lipid profile, it contains unsaturated fatty acids beneficial to health in patients with cardiovascular diseases and diabetes. In future research, it is necessary to investigate aspects related to germination processes, suitable soils for cultivation, and nutritional needs, in addition to its use in new food formulations and its applications in a greater number of pharmacological approaches. In the current context of the consumption of functional foods in the daily diet, the cachichín takes an important role due to its nutritional and bioactive components within the approach of nutraceutical products or foods.
... Plastomes, usually mapped as circular genomes, have numerous advantages for phylogenetic reconstruction, including mostly uniparental inheritance and a relatively conserved rate of evolution [41]. Recent advances in sequencing technology have made the acquisition of complete plastomes both practical and cost-effective, and an explosion of plastid phylogenomic studies has provided critical insights into historically difficult relationships of the major angiosperm subclades [22,26,[43][44][45]. Our previous work [13], the then-largest plastid phylogenomic angiosperm (PPA) tree comprising 2351 angiosperm species representing 353 families and all 64 then-recognized orders, provided a significant advance towards a robust familiallevel tree for angiosperms. ...
... However, both our previous work [13] and current study strongly supported (BP = 100) the monophyly of Oxalidales (excluding Huaceae), and Huaceae were placed as sister to Celastrales + Malpighiales with weak support in this study (BP = 34) here. In APG IV [18], Dasypogonaceae, Sabiaceae, and Oncothecaceae were placed in Arecales, Proteales, and Icacinales, respectively, according to the plastid phylogenomic studies of Barrett et al. [90], Sun et al. [44], and Stull et al. [43]. Nevertheless, in recent studies [45] and our study with denser taxon sampling, support for the monophyly of Arecales and Proteales was relatively low (BP < 80). ...
Article
Full-text available
Background Flowering plants (angiosperms) are dominant components of global terrestrial ecosystems, but phylogenetic relationships at the familial level and above remain only partially resolved, greatly impeding our full understanding of their evolution and early diversification. The plastome, typically mapped as a circular genome, has been the most important molecular data source for plant phylogeny reconstruction for decades. Results Here, we assembled by far the largest plastid dataset of angiosperms, composed of 80 genes from 4792 plastomes of 4660 species in 2024 genera representing all currently recognized families. Our phylogenetic tree (PPA II) is essentially congruent with those of previous plastid phylogenomic analyses but generally provides greater clade support. In the PPA II tree, 75% of nodes at or above the ordinal level and 78% at or above the familial level were resolved with high bootstrap support (BP ≥ 90). We obtained strong support for many interordinal and interfamilial relationships that were poorly resolved previously within the core eudicots, such as Dilleniales, Saxifragales, and Vitales being resolved as successive sisters to the remaining rosids, and Santalales, Berberidopsidales, and Caryophyllales as successive sisters to the asterids. However, the placement of magnoliids, although resolved as sister to all other Mesangiospermae , is not well supported and disagrees with topologies inferred from nuclear data. Relationships among the five major clades of Mesangiospermae remain intractable despite increased sampling, probably due to an ancient rapid radiation. Conclusions We provide the most comprehensive dataset of plastomes to date and a well-resolved phylogenetic tree, which together provide a strong foundation for future evolutionary studies of flowering plants.
... Phylogenomic analyses based on taxonomically sparse samples (exception: Li et al., 2019) have produced a different topology for each genome compartment: (1) plastid (Apocynaceae + Gentianaceae) + (Loganiaceae + Gelsemiaceae) (Stull et al., 2015(Stull et al., , 2020Li et al., 2019) (Fig. 2C); (2) nucleus (Apocynaceae + Loganiaceae) + (Gelsemiaceae + Gentianaceae) (Leebens-Mack et al., 2019;Stull et al., 2020;Zhang et al., 2020) (Fig. 2E); and (3) mitochondrion (Gelsemiaceae (Gentianaceae (Apocynaceae + Loganiaceae))) (Stull et al., 2020) (Fig. 2F). Interfamilial relationships are strongly supported only in the nuclear topologies. ...
... (B) Four plastid loci (Frasier, 2008); 17 plastid, nuclear, and mitochondrial loci (Soltis et al., 2011); three plastid loci (Struwe et al., 2014); plastome phylogenomic (this study, Appendix S3). (C) Nine plastid + 1 mitochondrial loci (Refulio-Rodriguez and Olmstead, 2014); plastome phylogenomic (Stull et al., 2015, Li et al., 2019Stull et al., 2020). (D) Eight plastid + 1 mitochondrial loci, sparse supermatrix (Yang et al., 2016). ...
Article
Full-text available
PREMISE: Comprising five families that vastly differ in species richness-ranging from Gelsemiaceae with 13 species to the Rubiaceae with 13,775 species-members of the Gentianales are often among the most species-rich and abundant plants in tropical forests. Despite considerable phylogenetic work within particular families and genera, several alternative topologies for family-level relationships within Gentianales have been presented in previous studies. METHODS: Here we present a phylogenomic analysis based on nuclear genes targeted by the Angiosperms353 probe set for approximately 150 species, representing all families and approximately 85% of the formally recognized tribes. We were able to retrieve partial plastomes from off-target reads for most taxa and infer phylogenetic trees for comparison with the nuclear-derived trees. RESULTS: We recovered high support for over 80% of all nodes. The plastid and nuclear data are largely in agreement, except for some weakly to moderately supported relationships. We discuss the implications of our results for the order's classification, highlighting points of increased support for previously uncertain relationships. Rubiaceae is sister to a clade comprising (Gentianaceae + Gelsemiaceae) + (Apocynaceae + Loganiaceae). CONCLUSIONS: The higher-level phylogenetic relationships within Gentianales are confidently resolved. In contrast to recent studies, our results support the division of Rubiaceae into two subfamilies: Cinchonoideae and Rubioideae. We do not formally recognize Coptosapelteae and Luculieae within any particular subfamily but treat them as incertae sedis. Our framework paves the way for further work on the phylogenetics, biogeography, morphological evolution, and macroecology of this important group of flowering plants.
... Few ontogenetic studies have been FIGURE 1. Major clades of the Boraginales. This topology is well supported based on plastid data (Weigend et al., 2014;Stull et al., 2015). BOR = Boraginales. ...
... Hydrophyllaceae and Namaceae were extensively sampled. Outgroup taxa include representatives of Gentianales, which is likely the sister order to Boraginales (Stull et al., 2015;Zhang et al., 2020). Information regarding names, voucher specimens and GenBank accessions can be found in Appendix S2. ...
Article
Full-text available
PREMISE: Fruit type and morphology are tightly connected with angiosperm diversification. In Boraginales, the first-branching families, including Hydrophyllaceae, have one-to many-seeded capsules, whereas most of the remaining families have four-seeded indehiscent fruits. This fact argues for many-seeded capsules as the ancestral condition. However, little is known about the evolution of fruit dehiscence and seed number. The present study investigated the gynoecium and fruit development and morphology and the evolution of seed-numbers in Hydrophyllaceae. METHODS: Gynoecium and fruit development and morphology were studied using scanning electron microscopy and x-ray microcomputed tomography. Ancestral character state reconstruction of seed number was performed using a broadly sampled phylogeny of Boraginales (ndhF and ITS) with an emphasis on Hydrophyllaceae. RESULTS: Our ontogenetic studies not only demonstrate parallel developmental trajectories across Hydrophyllaceae, but also a striking diversity regarding the internal organization of the gynoecium. Ovule number appears to determine ovary structure. Many-seeded capsules are retrieved as the ancestral state of Hydrophyllaceae. At least seven transitions to fruits with (one to) four seeds and four reversals (i.e., from four-to many-seeded fruits) were reconstructed in Hydrophyllaceae. CONCLUSIONS: Several shifts in seed number from “many” to “four” and back to “many” have taken place in capsular-fruited Hydrophyllaceae, a strikingly high number considering that seed number is virtually conserved across the rest of the order. The groups with a conserved seed number of four are characterized by indehiscent schizocarps or drupes and by seeds that are integrated into mericarps. This functional integration probably acts as an evolutionary constraint to shifts in seed number.
... Plastome rearrangements such as inversions and relocation of genes are used as informative markers to explore evolutionary relationships in angiosperms [76]. Since the complete plastome of Garrya sequenced by Stull et al. (2015) is still unavailable in the GenBank database [64], further investigation is needed to con rm whether this trait is a molecular synapomorphy for Eucommiaceae. ...
... The utilization of either too few DNA sequences or limited taxon sampling in phylogenetics may result in signi cant phylogenetic errors [81,82]. Notably, only six basal lamiid taxa were sampled in the current study in contrast to the 43 representatives included in the phylogenetic analyses of Stull et al. (2015). The weakly supported relationships recovered in this study can most likely be attributed to inadequate sampling of taxa within these basal lamiid orders. ...
Preprint
Full-text available
Backgroud: Aucuba (Garryaceae), which includes approximately 10 evergreen woody species, is a genus endemic to East Asia. Their striking morphological features give Aucuba species remarkable ornamental value. Owing to high levels of morphological divergence and plasticity, species definition of Aucuba remains perplexing and problematic. Here, we sequenced and characterized the complete plastid genomes (plastomes) of three Aucuba species: Aucuba chlorascens, Aucuba eriobotryifolia, and Aucuba japonica. Results: Comparative analyses revealed that Aucuba plastomes are highly conserved in size, structure, gene content, and organization, and exhibit high levels of sequence similarity. We recommend 11 plastid DNA regions as potential DNA barcodes for species identification and genotyping of Aucuba germplasm. Phylogenetic reconstruction based on 71 plastid protein-coding genes from taxa encompassing a wide phylogenetic diversity in the lamiids strongly supported the sister relationship between Garryaceae and Eucommiaceae. Conclusion: Plastome tree revealed the monophyly of Garryales, offering plastid phylogenomic evidence for the acceptance of Garryales as outlined by the updated Angiosperm Phylogeny Group. Under a comparative framework within Garryales, we detected massive plastome arrangements between Aucuba and Eucommia. In summary, our study provides useful genomic resources for further study of the taxonomy, evolution, conservation, and exploitation of Aucuba species.
... Solanales are the sister order to Lamiales + Vahliaceae [39] and primarily develop polysymmetric flowers. The Solanales model species, tomato (Solanum lycopersicum), is an ideal outgroup to study the ancestral function of the CYC-RAD-DIV-DRIF network. ...
Article
Full-text available
Background An outstanding question in evolutionary biology is how genetic interactions defining novel traits evolve. They may evolve either by de novo assembly of previously non-interacting genes or by en bloc co-option of interactions from other functions. We tested these hypotheses in the context of a novel phenotype—Lamiales flower monosymmetry—defined by a developmental program that relies on regulatory interaction among CYCLOIDEA , RADIALIS , DIVARICATA , and DRIF gene products. In Antirrhinum majus (snapdragon), representing Lamiales, we tested whether components of this program likely function beyond their previously known role in petal and stamen development. In Solanum lycopersicum (tomato), representing Solanales which diverged from Lamiales before the origin of Lamiales floral monosymmetry, we additionally tested for regulatory interactions in this program. Results We found that RADIALIS , DIVARICATA ,