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A species‐level phylogenetic framework and infrageneric classification for the genus Maesa (Primulaceae)

July 2023
Taxon 72(1)

July 2023
72(1)

DOI:10.1002/tax.12991

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CC BY 4.0

Authors:

Pirada Sumanon

Silpakorn University

Henrik Balslev

Aarhus University

Timothy M. A. Utteridge

Singapore Botanic Gardens

Wolf L. Eiserhardt

Aarhus University

The systematization of Maesa , a genus of almost 200 species, has haunted taxonomists for more than a century due to its lack of distinct qualitative characters or discontinuities in quantitative characters for species delimitation. The clarification of phylogenetic relationships in such a problematic genus like Maesa is essential to aid infrageneric classification and species delimitation. Here, a species‐level phylogenetic tree of Maesa is reconstructed. Leaf materials were sampled mainly from herbarium specimens which cover 60% of the species across the entire distribution range of the genus. Targeted sequence capture with the Angiosperms353 probe set was used to acquire sequences for downstream bioinformatic analyses. We obtained a species tree inferred from 310 gene trees that divides Maesa into an African clade and an Asian‐Pacific clade. The African clade is further divided into two subclades, while the Asian‐Pacific clade is divided into three subclades; all subclades are well supported. Hence, we propose five subgenera of Maesa , namely M. subg. Maesa , subg. Indicae , subg. Monotaxis , subg. Papuanae and subg. Ramentaceae . In addition, we scrutinize some species complexes within the genus; however, with the lack of phylogenetic signal at shallow levels, we are unable to conclusively resolve all species boundaries in these complexes. This study provides the phylogenomic framework to untangle taxonomic problems in the genus Maesa and lays the foundation for further detailed studies in biogeography, trait evolution and population genetics.

Coalescent tree of Maesa inferred from 310 gene trees with 200 tips analyzed with ASTRAL-III. Pie charts at the nodes represent the proportion of gene tree quartets concordant with the main topology (green section), the first alternative (orange) and the second alternative (white). Local posterior probabilities (LPP) are labelled at the nodes. The nodes with LPP = 1 were not labelled.

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Examples of species in the five subgenera proposed in this study. A & B, Maesa lanceolata from M. subg. Maesa (A with flowers and B with fruits); C, M. alnifolia from M. subg. Monotaxis; D, M. ramentacea from M. subg. Ramentaceae; E, M. perlaria var. formosana from M. subg. Indicae; F, M. bismarckiana from M. subg. Papuanae. -All photos with the permission of use: A by Bart Wursten, B by Mark Hyde, C by Garth Aiston, D by Theerawat Thananthaisong, E & F by Timothy Utteridge.

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Sequence retrieval of Angiosperms353 baits using the mega353 target file: Summary statistics from targeted sequencing for 220 samples of Maesa and 11 Ardisia species as outgroup.

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Alignment and gene trees statistics: Summary statistics for 310 alignments and gene trees used in the species tree inference.

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Figures - uploaded by Timothy M. A. Utteridge

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Content uploaded by Timothy M. A. Utteridge

Content may be subject to copyright.

A species-level phylogenetic framework and infrageneric classification

for the genus Maesa (Primulaceae)

Pirada Sumanon,

1,2

Henrik Balslev,

Timothy M.A. Utteridge

*& Wolf L. Eiserhardt

1,2

1Department of Biology, Aarhus University, Ny Munkegade 116, Aarhus C 8000, Denmark

2Royal Botanic Gardens, Kew, Kew Green, Richmond, Surrey, TW9 3AB, United Kingdom

*Joint senior authors

Address for correspondence: Wolf L. Eiserhardt, wolf.eiserhardt@bio.au.dk

DOI https://doi.org/10.1002/tax.12991

Abstract The systematization of Maesa, a genus of almost 200 species, has haunted taxonomists for more than a century due to its

lack of distinct qualitative characters or discontinuities in quantitative characters for species delimitation. The clarification of phylo-

genetic relationships in such a problematic genus like Maesa is essential to aid infrageneric classification and species delimitation.

Here, a species-level phylogenetic tree of Maesa is reconstructed. Leaf materials were sampled mainly from herbarium specimens

which cover 60% of the species across the entire distribution range of the genus. Targeted sequence capture with the Angiosperms353

probe set was used to acquire sequences for downstream bioinformatic analyses. We obtained a species tree inferred from 310 gene

trees that divides Maesa into an African clade and an Asian-Pacific clade. The African clade is further divided into two subclades,

while the Asian-Pacific clade is divided into three subclades; all subclades are well supported. Hence, we propose five subgenera

of Maesa, namely M. subg. Maesa, subg. Indicae, subg. Monotaxis, subg. Papuanae and subg. Ramentaceae. In addition, we scruti-

nize some species complexes within the genus; however, with the lack of phylogenetic signal at shallow levels, we are unable to con-

clusively resolve all species boundaries in these complexes. This study provides the phylogenomic framework to untangle taxonomic

problems in the genus Maesa and lays the foundation for further detailed studies in biogeography, trait evolution and population

genetics.

Keywords Ericales; Myrsinaceae; phylogeny; systematics; taxonomy

Supporting Information may be found online in the Supporting Information section at the end of the article.

■INTRODUCTION

“Genus vastum, difficillime systematice ordinandum, …”

“Vast genus, very difficult to arrange systematically”is

how Mez (1902) introduced the genus Maesa Forssk.

(Forsskål, 1775: 66) in his monograph on Myrsinaceae. With

ca. 192 species (Sumanon & al., 2020,2021, submitted;

POWO, 2021), but few systematically useful characters, this

genus has confused and haunted taxonomists for more than

a century (e.g., Smith, 1973: 3; Stone, 1989: 265). A phylog-

eny and classification of the genus would make it much more

manageable in the field and unlock it for evolutionary studies.

This is now achievable due to new methodological

developments.

Maesa is a genus of shrubs, trees or scramblers in Primu-

laceae s.l. (Bremer & al., 2009) distributed in tropical regions

of the Old World, longitudinally from Guinea to the Pacific as

far as Samoa and Tonga and latitudinally from Japan to

Queensland, Australia (POWO, 2021). The genus was

traditionally placed in the monogeneric subfamily Maesoi-

deae of Myrsinaceae, the former family of tropical Primula-

ceae. The position of Maesa in the phylogeny is well

resolved as sister to all other Primulaceae (Anderberg

& Ståhl, 1995; Anderberg & al., 1998; Källersjö & al.,

2000). A semi-inferior ovary, two bracteoles subtending each

flower and black glandular lines scattered on the leaves,

flowers and fruits of Maesa are diagnostic characters to distin-

guish the genus from other tropical Primulaceae (e.g., Ardisia

Sw., Embelia Burm.f.) (Sumanon & al., submitted).

Despite the ease to identify the genus, systematics and

species delimitation in Maesa are more troublesome. Maesa

species possess very small white-cream flowers that show

few distinctive characters and do not provide a suite of key

morphological characters useful for species delimitation.

Smith (1973) suggested that characters of indument, leaf, se-

cretory canals and inflorescences, utilized with caution, could

delimit populations that have a consistent suite of characters

and reasonable distribution. Thus, the combination of charac-

ters and geographic distribution is useful in Maesa for species

Article history: Received: 21 Dec 2021 | returned for (first) revision: 13 Jun 2022 | (last) revision received: 11 Apr 2023 | accepted: 13 Apr 2023

TAXON published by John Wiley & Sons Ltd on behalf of International Association for Plant Taxonomy.

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium,

provided the original work is properly cited.

Version of Record 1

TAXON 00 (00) •1–20 Sumanon & al. •Phylogeny and classification of Maesa

RESEARCH ARTICLE

delimitation and identification. The main diagnostic charac-

ters are habit (self-supporting [trees/shrubs] or non-

self-supporting [lianas/scramblers] main axis), indumentum

(type and distribution of hairs [pilose: >0.2 mm long; hispid:

0.1–0.2 mm long; hirsute: 0.05–0.1 mm long; hirsutellous:

<0.05 mm long] and scales), leaf morphology (size, shape,

apex, base, margin), inflorescence structure (simple or com-

pound racemose), floral merosity (tetramerous or pentamer-

ous) and bracteoles (shape: ovate or triangular; arrangement:

subopposite or alternate) (Sumanon & al., submitted).

However, the extent to which these characters have phyloge-

netic signal or systematic value to group taxa above the spe-

cies level is still unclear.

The genus was last monographed by Mez (1902), who di-

vided the 102 species known at the time into two subgenera:

Maesa subg. Monotaxis Mez (1902: 23) and subg. “Eumaesa

Mez”(Mez, 1902: 25). Maesa subg. Monotaxis is character-

ized by having a placenta with a uniseriate row of ovules

which are for the greater part sterile; this subgenus consists

of only four, morphologically similar, African species

(M. alnifolia Harv., M. schweinfurthii Mez, M. welwitschii

Gilg, M. zenkeri Gilg). The remaining taxa were placed in

M. subg. “Eumaesa”(a name not validly published that Mez

used for the taxa correctly named M. subg. Maesa); all these

species possess numerous ovules, which are usually all fertile,

in many rows attached to a placenta with a stipitate sterile

apex. Another subgeneric grouping was proposed by Miquel

(1861) who recognized 17 species of Maesa from the

“Netherlands Indies”(now Indonesia) (Miquel, 1859) and

split them into two sections based on floral merosity. Miquel’s

system seems to be unnatural because tetramerosity is occa-

sionally found in a few species which can also be pentamer-

ous, including M. macrothyrsa Miq., which is often

pentamerous, especially the populations in Peninsular

Malaysia. However, this character was used for Maesa identi-

fication in a recent taxonomic study of New Guinea taxa

(Sumanon & al., submitted). The use of floral merosity is crit-

ically reviewed for its taxonomical value due to its inconsis-

tency in some species; nevertheless, it is a practical character

for species identification when used with caution

(e.g., M. tetrandra (Roxb.) A.DC. always with tetramerous

flowers). The use of ovule characters in Mez’s system for sub-

generic classification has been questioned in other genera of

the Myrsinoideae (Taton, 1979). It would be more useful if in-

frageneric groupings are based on characters other than the

ovules and floral merosity because these are enigmatic and

difficult to observe.

Species delimitation in Maesa is also notoriously diffi-

cult, and the limits of many species are poorly defined. Some

widespread species show large variation in morphology

(e.g., M. haplobotrys F.Muell., M. indica (Roxb.) Sweet and

M. lanceolata Forssk. with diverse leaf shape and size) that

makes it difficult to draw a line for species delimitation. There

are no distinct qualitative characters or discontinuities in

quantitative characters in several problematic widespread spe-

cies, e.g., M. bismarckiana Mez, M. haplobotrys,M. indica

and M. montana A.DC. Thus, the species concept of those

taxa is applied in a broad sense with the suspicion that some

collections under these names may be distinct species. Not

only the status of some widespread species is questionable,

but also that of some range-restricted species. As most species

lack satisfactory diagnostic characters, it can be challenging to

make a taxonomic decision based solely on morphology, and

geography is often used to support species delimitation. Thus,

morphologically similar species from different islands may in

fact be best grouped together into a single, variable species

(a complex species) or into several, distinct taxa that merit in-

dividual recognition (a species complex). Since Mez’s mono-

graph (1902), taxonomic work on Maesa has focused only on

local revisions by different taxonomists, e.g., China (Chen

& Pipoly, 1996), Thailand (Larsen & Hu, 1996), the

Philippines (Utteridge & Saunders, 2004), Singapore

(Utteridge, 2021), New Guinea, the Moluccas, and the

Solomon Islands (Sleumer, 1987; Sumanon & al., submitted),

Micronesia (Fosberg & Sachet, 1979) and the Fijian region

(Smith, 1973). Each used different circumscriptions to distin-

guish the species, further complicating the picture.

For a taxon with limited taxonomically useful variation like

Maesa, molecular data can play an important role in resolving

relationships within the genus and establishing a useful system-

atic framework. To date, no phylogenetic studies have been

conducted on Maesa, and there is only limited molecular infor-

mation in GenBank, all derived from community-level barcod-

ing and higher-level systematic studies.Only one or two taxa of

Maesa have been included in family- or higher-level phyloge-

netic studies (Anderberg & Ståhl, 1995; Morton & al., 1996;

Anderberg & al., 1998; Källersjö & al., 2000; Baker &

al., 2022). Although Maesa is well placed as a sister clade to

all other genera of Primulaceae s.l. (Bremer & al., 2009), rela-

tionships within the genus remain unexplored. It is worth exam-

ining the infrageneric relationships of Maesa, not only for

untangling the problems of species delimitation but also for

studies of genomics, macroevolution and biogeography.

Plant systematics is currently in a transition period from

relying on few genetic markers to using genomic data ob-

tained from next-generation sequencing (NGS). The advanced

technology of NGS, or high-throughput sequencing, has es-

tablished a quicker and cheaper sequencing pipeline and rev-

olutionized phylogenetic studies in various plant groups

(Moore & al., 2018; Couvreur & al., 2019; Egan &

Vatanparast, 2019; Paetzold & al., 2019; Siniscalchi &

al., 2019). Importantly, NGS provides the possibility to work

with herbarium material, which is often impossible with

Sanger sequencing (Staats & al., 2013; Hart & al., 2016;

Bakker, 2017; Brewer & al., 2019; Strijk & al., 2020). This

is essential for a group of species with small distributions

across tropical islands such as Maesa, as obtaining fresh ma-

terial to cover the whole range of distribution would be prohib-

itively expensive. Targeted sequence capture (hybrid

sequence capture, hyb-seq, seq-cap, etc.) is a method using

DNA or RNA probes and PCR to enrich specific genomic

regions of interest instead of sequencing the whole genome.

2Version of Record

Sumanon & al. •Phylogeny and classification of Maesa TAXON 00 (00) •1–20

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The combination of sequence capture and high-throughput se-

quencing increases the chance to obtain genomic data to ana-

lyze the phylogeny of any selected plant group in detail and

with high resolution (Grover & al., 2012; Dodsworth

& al., 2019). Probes for targeted sequence capture have tradi-

tionally been designed for specif ic study groups, until the

Angiosperms353 probe set was developed, which targets

353 low-copy orthologous nuclear genes that are present and

phylogenetically informative across flowering plants

(Johnson & al., 2019; Baker & al., 2022).

Here, we use the Angiosperms353 probe set to generate

sequence data for a representative set of Maesa species, cover-

ing ca. 60% of the genus, relying mainly on herbarium mate-

rial. Using these data, we aim to: (1) generate a robust

species-level phylogeny of the genus; (2) present an infragene-

ric classification based on phylogenetically well-supported

clades and morphology, and (3) confront taxonomically diffi-

cult species with phylogenetic evidence.

■MATERIALS AND METHODS

Taxon sampling. —To guide our DNA sampling, we

generated an initial species list of Maesa using the World

Checklist of Vascular Plants (WCVP; Govaerts & al., 2021)

and POWO (2021). We then refined this list following our re-

cent revision of Maesa in New Guinea (Sumanon & al., sub-

mitted), adding newly described species that are not

included in the WCVP yet. We then reviewed all accepted

names and synonyms and made some changes. In total, our

Maesa species list includes 192 species.

Our sampling strategy of Maesa was based on three cri-

teria. First, we tried to sample at least one specimen per spe-

cies and cover the entire geographical range of the genus.

Second, for widely distributed species (e.g., M. indica,

M. lanceolata,M. montana), we selected multiple specimens

covering the distribution range. Third, for species complexes

or complex species that show morphological variation

(e.g., M. bismarckiana,M. haplobotrys), we sampled multiple

specimens which showed morphological variations, especially

in leaf characters, to test species limits. Finally, we added

some dubious specimens which show distinct morphology.

In total, 220 leaf samples of Maesa from 136 taxa were sam-

pled (suppl. Table S1). Of these, f ive were silica-dried sam-

ples, and the remainder was taken from herbarium

specimens. After data filtering in our bioinformatic pipeline,

189 accessions of Maesa from 126 taxa were included.

Vouchers of the accessions are presented in Appendix 1.

For outgroups, we used raw reads of 11 Ardisia species

generated by a team at the Royal Botanic Gardens, Kew, fol-

lowing the protocol from Baker & al. (2022).

DNA extraction, library preparation and sequencing.

—DNA was extracted from leaf material using a modified ce-

trimonium bromide (CTAB) protocol (Doyle & Doyle, 1987).

For difficult samples, we applied a sorbitol prewash protocol

(Inglis & al., 2018) as an additional step prior to CTAB

extraction. DNA concentrations were measured using an Invi-

trogen Qubit 2.0 Fluorometer (Thermo Fisher Scientific, Wal-

tham, Massachusetts, U.S.A.) and DNA fragment sizes were

assessed using gel electrophoresis.

Prior to library preparation for targeted sequence capture,

extracts with DNA fragment sizes larger than 1000 bp were

sheared using a Covaris S220 focused-ultrasonicator

(Covaris, Wobum, Massachusetts, U.S.A.) to get fragment

sizes around 300–400 bp. Libraries were prepared from

(50–)250 ng input DNA using the NEBNext Ultra II library

prep kit for Illumina (New England Biolabs, Hitchin, U.K.)

following the manufacturer’s protocol but using half volumes

where possible (Hale & al., 2020). Size selection and cleanup

step were performed with AMPure XP magnetic beads

(Beckman Coulter, High Wycombe, U.K.), dual indexing

with NEBNext Multiplex Oligos for Illumina (New England

Biolabs), and PCR enrichment with 8–12 cycles. Prepared li-

braries were assessed for DNA concentration using Invitrogen

Qubit 2.0 Fluorometer with Qubit dsDNA HS Assay Kit

(Thermo Fisher Scientific) and for distribution of DNA frag-

ment lengths using an Agilent 4200 TapeStation system

(Agilent Technologies, Stockport, U.K.). Ten to twenty-eight

indexed libraries of similar DNA fragment length distribu-

tions were combined with equal amounts of DNA into pools

of 1000–2000 ng DNA.

Hybridization was performed using the myBaits Expert

Angiosperms353 hybridization capture kit (Arbor Biosci-

ences, Ann Arbor, Michigan, U.S.A.) (Johnson & al., 2019).

We followed the standard protocol from user manual version

5.00 provided by the manufacturer (September 2020). Hybrid-

ized DNA was pooled into sequencing pools and sent to No-

vogene Europe (Cambridge, U.K.) for sequencing on an

Illumina Novaseq 6000 platform (Illumina, San Diego, Cali-

fornia, U.S.A.), generating 2 × 150 bp read length (PE150)

or 2 × 250 bp read length (PE250) depending on the quality

of sequencing pools.

Phylogeny reconstruction. —Adapters and low-quality

bases were trimmed from raw sequence data using Trimmo-

matic v.0.39 (Bolger & al., 2014) with the MAXINFO algo-

rithm with strictness 0.5, and reads shorter than 36 bp were

eliminated. Read quality was assessed before and after trim-

ming using FastQC v.0.11.9 (Andrews, 2019). Cleaned reads

were processed with the HybPiper pipeline (Johnson

& al., 2016) starting with using BWA v.0.7.17 (r1188) to

map reads to the Angiosperms353 targets. We used the

mega353 target file (McLay & al., 2021), an improved target

file for the Angiosperms353 probe set, which has been shown

to increase percentage of on-target reads, locus recovery and

total length of concatenated loci. Then, reads were assembled

to each locus with SPAdes v.3.13.0 (Bankevich & al., 2012).

Potential paralogs were detected by the script implemented

in HybPiper and excluded from downstream analyses. Super-

contigs, which comprised exons and “splash zones”, were re-

trieved and used for downstream analyses.

Supercontigs of each locus were aligned using MAFFT

v.7.475 (Katoh & Standley, 2013) with local pairwise

Version of Record 3

TAXON 00 (00) •1–20 Sumanon & al. •Phylogeny and classification of Maesa

alignments, 1000 iterative refinements and reverse comple-

mentation of sequences if necessary. Fragmentary sites of

the alignments were removed using the optrimAl script (Shee

& al., 2020). OptrimAl defined an optimum threshold for

trimming that provided the maximum proportion of

parsimony-informative characters without losing data more

than one median absolute deviation above the median data

loss across the entire range of trimming thresholds being

tested. The trimmed alignments were then inspected and fur-

ther cleaned manually in an alignment editor program.

A set of 10 maximum likelihood trees generated with IQ-

TREE v.2.0.3 (Minh & al., 2020) for each alignment was used

to detect rogue taxa using the RogueNaRok (RNR) algorithm

(Aberer & al., 2013). Although there are other ways of rogue

detection (Wilkinson & Crotti, 2017), RNR is suitable to im-

plement in the pipeline for a phylogenomic dataset. We set

the dropset size to 2, as recommended in the RNR tutorial.

Detected rogues were pruned from the alignments. After that,

preliminary gene trees were generated using IQ-TREE v.2.0.3

(Minh & al., 2020) with 1000 ultrafast bootstrap replicates and

joint model testing in ModelFinder (Kalyaanamoorthy &

al., 2017). Long branches that indicated possible sequence

errors were detected using TreeShrink v.1.3.7 (Mai &

Mirarab, 2018) and removed from the alignments.

The alignments from the previous step were used to per-

form gene tree estimation in IQ-TREE v.2.0.3 (Minh

& al., 2020) with the same setting as above. Each gene tree

was rooted using phyx v.1.3 (Brown & al., 2017). Following

Baker & al. (2022), internal branches which had ultrafast

bootstrap support below 30% were collapsed using Newick

utilities v.1.6 (Junier & Zdobnov, 2010). Then a species tree

was inferred from all individual gene trees using the

coalescent-based method ASTRAL v.5.7.5 (Zhang & al.,

2018). In addition, a test for polytomies was performed using

the -t 10 function implemented in the ASTRAL package (Say-

yari & Mirarab, 2018).

Tree visualization. —A species tree obtained from the

analysis was visualized in R v.4.0.3 (R Core Team, 2020)

using the ape v.5.4.1 (Paradis & Schliep, 2019), geiger

v.2.0.7 (Pennell & al., 2014), adephylo v.1.1.11 (Jombart

& al., 2010), treeio v.1.14.4 (Wang & al., 2020), and phytools

v.0.7.70 (Revell, 2012) packages. We followed POWO (2021)

for the geographic distribution of each taxon along with spec-

imen locality information. The geography was divided into

nine areas (Africa, Borneo, continental Asia, Philippines,

Thai-Malay Peninsula, Sumatra, Java, Sulawesi and Papua-

Pacific including Maluku). Leaf margin (entire, serrulate or

serrate) and habit (trees/shrubs or scramblers) were scored

based on observations of specimens and description of the

species.

Data availability. —Raw sequence data are deposited

in Sequence Read Archive (SRA) available on NCBI servers

under BioProject number PRJNA774956 (http://www.ncbi.

nlm.nih.gov/bioproject/774956). All scripts related to phylo-

genetic analyses are available on GitHub at https://github.

com/pebgroup/Maesa_sptree. The alignments, gene trees,

and species trees are deposited on Zenodo at 10.5281/

zenodo.5602045.

■RESULTS

Sequencing results. —Targeted sequencing of the

Angiosperms353 loci produced between 1043 and

11,599,684 trimmed reads per sample, and a median of

38.75% were on target (Table 1). There were three samples

for which we obtained fewer than 100,000 reads: de Vogel

5544 (M. haplobotrys: 96,786 reads), Robinson 1242

(M. subdendata A.DC.: 1043 reads) and Parker s.n.

(M. lanceolata [former M. emirnensis A.DC.]: 1190 reads),

and no sequence was retrieved from these samples. Reads of

these samples could not be mapped to the target loci; so, these

samples were excluded from downstream analyses. After as-

sembly of the reads to the target reference, we could retrieve

352 loci of which 23 received paralog warnings and were ex-

cluded from the analyses. The median of loci retrieved per

sample was 278 (Table 1).

After alignment cleaning, rogue pruning, blacklisting

samples with suspicious sequences and removing alignments

that contained only Maesa sequences but no outgroup se-

quence needed for rooting in the downstream process, 310

alignments remained for downstream analyses (Table 2).

Table 1. Sequence retrieval of Angiosperms353 baits using the mega353 target file: Summary statistics from targeted sequencing for 220 samples of

Maesa and 11 Ardisia species as outgroup.

Reads total Reads on target

Number of recovered exons longer than X%

of the target sequence length

# # % X=0X=25X=50X=75

Maesa Minimum 1,043 305 7.5 0 0 0 0

Q1 1,359,536.75 444,111.25 32.5 72.75 34 5.75 2

Median 2,309,356 920,138.5 38.75 278 207.5 93 36.5

Q3 3,506,546 1,506,574.75 49.75 335 316.5 249.5 157.25

Maximum 11,599,684 6,486,844 87.2 352 347 333 287

Outgroup Median 3,602,289 907,954 24 124 66 31 16

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Sumanon & al. •Phylogeny and classification of Maesa TAXON 00 (00) •1–20

The trimmed supercontig alignments had a total length of

428,372 bp covering 200 samples with 58.3% missing data.

Of the columns, 33.1% were variable and 18.7% were parsi-

mony informative.

The statistics for individual gene alignments and gene

trees are reported in Table 2. Across the 310 gene alignments,

the median number of samples per gene alignment was

117 (114.53 ± 22.1), the median of the percentage of samples

presented in the alignment/gene tree was 58.5 (57.26 ± 11.05)

and the median alignment length was 1111.5 (1381.85

± 838.51). With only exons, the median of variable sites per

alignment was 154 (181.2 ± 134.87) or 27.7% (28 ± 6.16%).

Flanking regions gave additional variable sites resulting in

supercontigs with a median number of 231 (276.77 ± 188.4)

or 36.25% (36.79 ± 7.66%) per alignment.

Tree topology and branch support. —The resulting

gene trees had a median ultrafast bootstrap support across all

nodes of 80% (78.25 ± 11.04%), and 11.42% of all nodes in

all gene trees were poorly supported (bootstrap <30%) and

were collapsed prior to species tree inference. The species tree

inferred from 310 gene trees included 80% of the quartet trees

induced from the gene trees (ASTRAL normalized quartet

score of 0.80), and the average nodal support of local posterior

probability (LPP) was 0.765. Of the nodes in the species tree,

48.74% were well-supported (LPP ≥0.95), and only 37 nodes

were informed by fewer than 10 gene trees.

The species tree supports the monophyly of Maesa

(Fig. 1). Within the genus, two clades are clearly separated

with high support (quartet score & LPP = 1). The first clade

includes all taxa distributed in Africa, and the second clade in-

cludes all taxa distributed in Asia and the Pacific. The African

taxa are separated into two subclades: (1) the Monotaxis clade

(Fig. 2C), a group of M. alnifolia and M. welwitschii,and

(2) the Maesa clade (Fig. 2A,B), a group of M. lanceolata,

M. kivuensis Taton, M. angolensis Gilg, M. nuda Hutch. &

Dalziel, Maesa sp. 3, M. rufescens A.DC., M. kamerunensis

Mez, M. borjaeana Henriq. There are three main subclades

for the Asian-Pacific taxa: (1) the Ramentaceae clade

(Fig. 2D), sister to the other two subclades, comprises

M. ramentacea (Roxb.) A.DC., M. tomentella Mez, M. pro-

cera B.C.Stone, M. decidua Philipson, M. impressinervis King

&Gamble,M. inculticola Utteridge, M. oligotricha Merr.,

M. cordifolia Miq., M. malayana Utteridge, M. leptobotrya

Hance, M. fraseriana Utteridge and M. sumatrana Scheff.;

Table 2. Alignment and gene trees statistics: Summary statistics for 310 alignments and gene trees used in the species tree inference.

Median Mean SD Min Max

Number of taxa 117 114.53 22.1 9 160

%Occupancy 58.5 57.26 11.05 4.5 80

Supercontigs Alignment length 1111.5 1381.85 838.51 270 5288

%missing data 28.95 28.97 7.37 8.44 46.24

Number of variable sites 387.5 457.97 291.58 15 2185

%variable sites 32.95 32.91 5.42 5.6 51.5

Parsimony-informative sites 225 258.06 162.52 9 1215

%parsimony-informative sites 18.6 18.7 4.14 3.3 30.9

Exons Alignment length 542 632.92 419.35 63 2725

%missing data 19.64 19.47 8.31 0 41.24

Number of variable sites 154 181.2 134.87 6 1080

%variable sites 27.7 28 6.16 8 51.3

Parsimony-informative sites 92.5 113.95 85.32 5 625

%parsimony-informative sites 17.65 17.63 4.79 3.6 33.6

Flanking regions Alignment length 620.5 748.93 493.57 40 2563

%missing data 36.68 37.08 8.62 13.35 63.05

Number of variable sites 231 276.77 188.4 3 1105

%variable sites 36.25 36.79 7.66 2.5 66.8

Parsimony-informative sites 121.5 144.11 97.48 0 590

%parsimony-informative sites 18.7 19.43 5.8 0 42.7

Gene trees %nodes in gene trees above 30% BS 88.58 85.99 9.45 40 99.33

Mean support of all nodes 71.19 70.24 8.43 36.59 87.67

Median support of all nodes 80 78.25 11.04 23 98

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TAXON 00 (00) •1–20 Sumanon & al. •Phylogeny and classification of Maesa

0.90

0.42

0.33

0.37

0.76 0.81

0.85

0.95

0.97

0.56

0.44

0.95

0.40

0.62

0.97

0.54

0.32

0.33

0.98

0.37

0.38

0.870.67

0.55

0.97

0.89

0.59

0.67

0.99

0.50

0.42

0.330.67

0.67

0.57

0.82

0.64

0.58

0.96

0.50

0.99

0.86

0.47

0.33

0.47

0.22

0.31 0.89

0.45

0.95

0.83

0.98

0.69

0.67

0.81

Outgroups IndicaeRamentaceaeMaesaMonotaxis

Ardisia lanceolata

Ardisia sumatrana

Ardisia celebica

Ardisia copelandii

Ardisia steiranthera

Ardisia amabilis

Ardisia diversilimba

Ardisia oocarpa

Ardisia tinifolia

Ardisia elmeri

Ardisia guianensis

Maesa alnifolia

Maesa welwitschii 5[M. zenkeri]

Maesa welwitschii 1

Maesa welwitschii 4[M. schweinfurthii]

Maesa welwitschii 2

Maesa welwitschii 3

Maesa lanceolata 4

Maesa lanceolata 3

Maesa lanceolata 2

Maesa lanceolata 1

Maesa kivuensis

Maesa angolensis

Maesa sp. 3

Maesa nuda

Maesa rufescens

Maesa kamerunensis

Maesa borjaeana

Maesa ramentacea 2

Maesa ramentacea 1

Maesa tomentella

Maesa procera

Maesa decidua

Maesa impressinervis

Maesa inculticola

Maesa oligotricha

Maesa cordifolia

Maesa malayana

Maesa leptobotrya 1

Maesa leptobotrya 2

Maesa fraseriana

Maesa sumatrana 1

Maesa sumatrana 2

Maesa chisia

Maesa rugosa 1

Maesa rugosa 2

Maesa palauensis

Maesa macrocarpa

Maesa laxiflora 1

Maesa laxiflora 2

Maesa acuminatissima 1

Maesa acuminatissima 2

Maesa brevipaniculata

Maesa japonica 2

Maesa japonica 1

Maesa salicifolia

Maesa balansae

Maesa cf. striata

Maesa calophylla 2

Maesa calophylla 1

Maesa hupehensis

Maesa laxa 1[M. indica]

Maesa laxa 2[M. indica]

Maesa pahangiana

Maesa paniculata

Maesa integrifolia

Maesa macrophylla

Maesa argentea 1

Maesa argentea 2

Maesa permollis 2

Maesa argyrophylla

Maesa permollis 1

Maesa indica 3

Maesa indica 1

Maesa indica 5[M. perrottetiana]

Maesa sp. aff. perlaria

Maesa junghuhniana

Maesa indica var. wightiana

Maesa permollis var. effusa

Maesa lineolata

Maesa brachybotrya

Maesa andamanica

Maesa montana 4

Maesa kurzii

Maesa maxima

Maesa martiana

Maesa indica 4[M. elongata]

Maesa pisocarpa

Maesa warburgii 1

Maesa warburgii 2

Maesa parvifolia 2

Maesa parvifolia 1

Maesa bengalensis

Maesa denticulata

Maesa cambodiana

Maesa membranacea

Maesa montana 3

Maesa indica 2

Maesa montana 5

Maesa montana 2

Maesa pilosa

Maesa montana 6[M. henryi]

Maesa montana 1

Maesa perlaria 1

Maesa perlaria 2

Maesa tenera 2

Maesa perlaria var. formosana

Maesa tenera 1

Geography

Leaf margin

Habit

Fig. 1. Coalescent tree of Maesa inferred from 310 gene trees with 200 tips analyzed with ASTRAL-III. Pie charts at the nodes represent the pro-

portion of gene tree quartets concordant with the main topology (green section), the first alternative (orange) and the second alternative (white).

Local posterior probabilities (LPP) are labelled at the nodes. The nodes with LPP = 1 were not labelled.

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Sumanon & al. •Phylogeny and classification of Maesa TAXON 00 (00) •1–20

Geography

Africa

Borneo

Continental Asia

Java

Papua-Pacific

Philippines

Sulawesi

Sumatra

Thai-Malay Peninsular

Leaf margin

entire

serrate

serrulate

Habit

scrambler

tree/shrub

0.67 0.33

0.98

0.71

0.85

0.99

0.51

0.89 0.33

0.67

0.99

0.67

0.68

0.93

0.91 0.72

0.28

0.67

0.48

0.69

0.29

0.66

0.33

0.68

0.89

0.61

0.67

0.80

0.40

0.99

0.66

0.41

0.22

0.24

0.78

0.77

0.71

0.91

0.37

0.89

0.78

0.77

0.94

0.64

0.39

0.67

0.46

0.76

0.49

0.67

0.82

0.72

0.98

0.94

0.97

0.95

0.94

0.39

0.59

Papuanae

Geography

Leaf margin

Habit

0.67

Maesa macrothyrsa 1

Maesa macrothyrsa 2

Maesa lobuligera

Maesa cumingii

Maesa gaudichaudii

Maesa novocaledonica

Maesa brevipedicellata 3

Maesa brevipedicellata 1

Maesa brevipedicellata 2

Maesa spectabilis 1

Maesa spectabilis 2

Maesa montis-wilhelmi 1

Maesa montis-wilhelmi 2

Maesa sayersii 2

Maesa sayersii 1

Maesa corneri

Maesa sleumerii 2

Maesa sleumerii 1

Maesa protracta

Maesa dependens

Maesa muelleri

Maesa sp. 2

Maesa sp. aff. tetrandra

Maesa cauliflora

Maesa reflexa

Maesa rufovillosa 4

Maesa rufovillosa 1

Maesa rufovillosa 3

Maesa angustibracteolata

Maesa tagulensis

Maesa sp. 1

Maesa sp. johnsii

Maesa loranthifolia

Maesa rufovillosa 2

Maesa fruticosa

Maesa beamanii

Maesa decipiens

Maesa ruficaulis 2

Maesa ruficaulis 1

Maesa ruficaulis 3

Maesa novoguineensis

Maesa purpureohirsuta

Maesa calcarea

Maesa rubiginosa

Maesa tetrandra 2

Maesa tetrandra 3

Maesa tetrandra 1

Maesa tetrandra 4

Maesa procumbens

Maesa sp. mayuii

Maesa pilosopapuana

Maesa papuana 1

Maesa papuana 2

Maesa bismarckiana 3

Maesa carolinensis 2

Maesa bismarckiana 4[M. serpentinopicta]

Maesa bismarckiana 1

Maesa bismarckiana 2

Maesa serratifolia

Maesa haplobotrys 1

Maesa rheophytica

Maesa haplobotrys 2

Maesa aurulenta

Maesa haplobotrys 7

Maesa haplobotrys 6

Maesa carolinensis 1

Maesa banksiana

Maesa regia

Maesa edulis

Maesa corylifolia 2

Maesa tongensis 2

Maesa tongensis 1

Maesa tongensis 4

Maesa tongensis 3

Maesa tabacifolia

Maesa aneiteensis

Maesa nemoralis 1

Maesa nemoralis 2

Maesa ambrymensis

Maesa aubertii

Maesa eramangensis

Maesa vitiensis 1

Maesa samoana

Maesa vitiensis 3

Maesa vitiensis 2

Maesa pickeringii

Maesa insularis

Maesa persicifolia

Maesa corylifolia 1

Maesa pusilliflora

Maesa haplobotrys 4

Maesa haplobotrys 3

Fig. 1. Continued.

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TAXON 00 (00) •1–20 Sumanon & al. •Phylogeny and classification of Maesa

(2) the Indicae clade (Fig. 2E) comprises the rest of the Asian

taxa except scrambling taxa from the Philippines and Borneo

and (3) the Papuanae clade (Fig. 2F) comprises taxa from

New Guinea, Australia, Pacif ic islands and scrambling taxa

from the Philippines and Borneo.

High local posterior probabilities (LPP = 1) support all

crown nodes of the main clades described above, as well as all

nodes in the backbone connecting them, except the node uniting

the Indicae and Papuanae clades. This node has low LPP (0.38)

and equal proportions of concordant and discordant gene tree

quartets in pie charts showing that all topologies at this position

have roughly equal probabilities (Fig. 1). In addition, the branch

at this node is notably short in coalescent units, indicating low

support. We ran a polytomy test implemented in the ASTRAL

package, yielding a p-value >0.05 at this node (0.9787) thus fail-

ing to reject the null hypothesis of a polytomy.

Multiple accessions were sequenced for 36 species and

included in the species tree (Appendix 1). Of those species,

the accessions of Maesa bismarckiana,M. carolinensis Mez,

M. corylifolia A.Gray, M. haplobotrys,M. indica,M. japonica

(Thunb.) Moritzi ex Zoll., M. montana,M. permollis Kurz,

M. ramentacea,M. rufovillosa Mez, M. rugosa C.B.Clarke,

M. tenera Mez, and M. vitiensis Seem., are polyphyletic or

paraphyletic.

Fig. 2. Examples of species in the five subgenera proposed in this study. A&B,Maesa lanceolata from M. subg. Maesa (A with flowers and B with

fruits); C,M. alnifolia from M. subg. Monotaxis;D,M. ramentacea from M. subg. Ramentaceae;E,M. perlaria var. formosana from M. subg.

Indicae;F,M. bismarckiana from M. subg. Papuanae.—All photos with the permission of use: A by Bart Wursten, B by Mark Hyde, C by Garth

Aiston, D by Theerawat Thananthaisong, E & F by Timothy Utteridge.

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■DISCUSSION

Based on the first phylogenetic tree of Maesa, we propose

a new subgeneric classification that reflects evolutionary his-

tory. Our species tree presents two main clades of Maesa –

the African and Asian-Pacific clades which are further divided

into five monophyletic groups. We assign the rank of subge-

nus to these f ive groups of Maesa, named M. subg. Maesa,

subg. Monotaxis, subg. Ramentaceae, subg. Indicae and subg.

Papuanae; all groups have strong support as outlined in the

Results (Fig. 1).

The efficacy of using herbarium materials and Angio-

sperms353 probes in phylogenomic study of Maesa.—

Herbarium collections are a treasure trove for systematic

studies because it is a cost effective way to sample specimens

from diverse geographic localities. Herbarium specimens will

likely become the main source of material for phylogenomic

studies, especially for generating species-level trees (Staats

&al.,2013; Bakker, 2017). For Maesa, herbarium specimens

provided material for many species with restricted ranges as

well as species representing most of the morphological diver-

sity of the genus. Of the 215 herbarium specimens used in this

study, we were able to retrieve and utilize sequences from 189

(87.9%), regardless of specimen age. However, even using

the extensive herbarium collections of Southeast Asian and

African plants at K and AAU, we were only able to obtain

viable samples of less than two-thirds of the Maesa species.

Thus, herbaria are no “silver bullet”for the difficulty of

obtaining high-quality DNA material, and continued field

work is paramount to obtain a more complete picture of the

species-level diversif ication of this genus and likely many

other taxa.

Factors such as climate, taxon-specific traits (e.g., leaf

texture and thickness, secondary metabolites; Särkinen

& al., 2012; Kates & al., 2021) and collection method seem

to be more important indicators of targeted sequencing suc-

cess than sample age (Brewer & al., 2019; Kates & al.,

2021); our results agree with these f indings. The samples of

Maesa oblanceolatifolia Sumanon & Utteridge could be a

good example for a taxon-specific trait related to targeted se-

quence recovery. There were four accessions included in our

study, with the most recent collections dating from 2008–

2009, but none yielded a sequence that could be used in down-

stream analyses (suppl. Table S1).

The Angiosperms353 probes (Johnson & al., 2019) used

in conjunction with the expanded “mega353”target file

(McLay & al., 2021) provided sufficient information to re-

solve the deep relationships within the genus Maesa, except

the relationships between three clades of Asian-Pacific taxa,

and revealed five clades within Maesa with strong support.

However, the retrieved sequences were not informative en-

ough to provide well-resolved relationships at shallow levels

within Asian-Pacific taxa. To address the incomplete resolu-

tion of the shallow nodes, a specific probe set may be needed

instead of using a universal one like Angiosperms353 (Kadlec

& al., 2017; Chau & al., 2018).

Phylogeny and infrageneric classification. —Within

the genus, the African taxa are all resolved in the African clade

and clearly separated from the Asian-Pacific taxa. Within the

African clade, there are two subclades, corresponding to

Maesa subg. Monotaxis (Fig. 2C) and subg. Maesa

(Fig. 2A,B). Maesa subg. Monotaxis was described by Mez

(1902) where he proposed to classify Maesa into two subge-

nera named Monotaxis and “Eumaesa”based on ovule charac-

ters. His M. subg. Monotaxis consisted of four African species

(M. alnifolia,M. schweinfurthii,M. welwitschii,M. zenkeri),

all having a placenta with a uniseriate row of ovules which

are mostly sterile (Mez, 1902). Our study confirms the taxo-

nomic value of this character for subgeneric classification of

Maesa, and two species are included in M. subg. Monotaxis

(M. alnifolia,M. welwitschii). Maesa schweinfurthii was syn-

onymized with M. welwitschii by Darbyshire & al. (2015), and

our results agree with that decision since the specimen

“M. welwitschii 4”in the tree was determined as

M. schweinfurthii in K but is nested within a clade with the re-

maining M. welwitschii specimens. Maesa zenkeri was also

synonymized with M. welwitschii (Govaerts & al., 2021).

Our tree shows that the sample “M. welwitschii 5”, which

was determined as M. zenkeri, is sister to all the other

M. welwitschii samples. These two species do not have distinct

characters to distinguish one from another. From the protolo-

gue, M. welwitschii has a longer petiole (1.5–2 cm long,

M. zenkeri: 0.7–0.9 cm long), bigger leaf (5–7.5 cm long,

4–5 cm wide, M. zenkeri:3–5 cm long, 1.5–2.5 cm wide)

(Gilg, 1895: 72, 1901: 100). From this evidence, we agree

with WCVP (Govaerts & al., 2021) to consider M. zenkeri

as a synonym of M. welwitschii.

The Maesa clade includes the type species of the genus,

Maesa lanceolata, and consists of seven species. The clade

is separated into two groups, (1) a M. lanceolata group, and

(2) a group comprising the rest of the African species

(Fig. 1). Maesa lanceolata is widespread in tropical Africa,

the Arabian Peninsula and Madagascar. It has 18 synonyms

(Govaerts & al., 2021) and two subspecies. Maesa angolensis

and M. rufescens have previously been synonymized with

M. lanceolata (Exell & Wild, 1960; Troupin, 1985; Figuei-

redo & Smith, 2008), while M. borjaeana was reduced to a

subspecies as M. lanceolata subsp. borjaeana (Figueiredo

&al.,2011). However, the tree shows that M. angolensis,

M. borjaeana and M. rufescens are not included in the mono-

phyletic clade formed by our four samples of M. lanceolata.

They, instead, form a clade with M. kamerunensis,M. nuda

and M. kivuensis. Hence, we recognize M. angolensis,

M. borjaeana and M. rufescens as accepted species. In total,

within the two subgenera, we accept 10 species in Africa.

More taxonomical aspects need to be reconsidered within

the Maesa clade. For example, first, even though the species

tree gives us more insight about M. lanceolata, the delimita-

tion of this species is still ambiguous. We could not sample

all 18 synonyms of the species to examine the whole species

complex and decide on species delimitation. In addition,

the M. lanceolata clade includes samples with distinct

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TAXON 00 (00) •1–20 Sumanon & al. •Phylogeny and classification of Maesa

morphological variation, e.g., two samples with serrate leaves

(“M. lanceolata 2”,“M. lanceolata 3”), and two samples with

entire leaves (“M. lanceolata 1”[this sample also has large

lanceolate leaves], “M. lanceolata 4”). Second, there are two

species that are morphologically extremely similar. The sam-

ple of M. borjaeana is placed with M. kamerunensis: both spe-

cies have a climbing habit, ovate leaves with acute apex,

rounded base and entire margin, and panicle inflorescences.

We do not make any changes to the nomenclature in this study

as more detailed sampling and morphological observations

are needed. Maesa vestita Jacq.-Fél. is the only African spe-

cies that we were unable to include in the analysis; however,

we provisionally place it in M. subg. Maesa based on its distri-

bution and the presence of numerous ovules in many rows at-

tached to the placenta (see Jacques-Félix, 1970: pl. 1E).

The Asian-Pacific taxa have a more complicated story to

interpret. There are approximately 182 accepted species in this

region, and the species tree divides them into three main

groups, which we describe as Maesa subg. Ramentaceae

(Fig. 2D), subg. Indicae (Fig. 2E) and subg. Papuanae

(Fig. 2F). However, the relationships between these three

groups are not well-resolved as the Papuanae and Indicae

clades are only joined by a short branch (in coalescent units).

A polytomy test failed to reject the null hypothesis that the

branch length is equal to zero, supporting the presence of a

polytomy for the node. Distinguishing between soft and hard

polytomy is difficult (Sayyari & Mirarab, 2018), and the

causes of this unresolved node may be either the lack of infor-

mation in our study or a real biological event. Plants in the or-

der Ericales showed evidence of rapid diversification at many

positions in a phylogenetic tree (Larson & al., 2020), and this

may also apply to the genus Maesa. The hard polytomy may

be a result of rapid diversification of their common ancestor

to occupy each area of the current distribution. Further studies

are needed to confirm the nature of the polytomy at this

position.

Despite the unresolved relationships at the crown node of

the Asian-Pacific taxa, all three subclades are strongly sup-

ported, and we assign the rank of subgenus to each of the

clades. All three subgenera show signs of geographic separa-

tion (Fig. 1). Maesa subg. Ramentaceae includes samples

from the Thai-Malay Peninsula, Sumatra, Java, and Borneo.

Most members of this subgenus exhibit entire leaf margins

(Fig. 2D). On the other hand, M. subg. Indicae is mainly dis-

tributed in continental Asia (India, Myanmar, China, Indo-

china), Taiwan and Japan and exhibits serrate leaf margins

(Fig. 2E). The last subgenus of Asian-Pacific taxa is M. subg.

Papuanae, which comprises species mainly from New

Guinea, Australia and Pacific Islands (Fig. 2F). Within the

Papuanae clade, scrambler taxa from the Philippines and Bor-

neo form a sister group to the rest of the clade. New Guinean

taxa are not a monophyletic group and form a grade which has

given rise to species found on West Pacific islands

(Solomon Islands, Vanuatu, Fiji, Tonga, Samoa). This is in-

congruent with previous studies of floristic patterns and bio-

geography of the region (Marsh & al., 2009; Ung &

al., 2016). Floristic relationships at generic level showed that

New Guinea was aligned closer to Malesia than to the Bis-

marck Archipelago and the Solomon Islands (Marsh &

al., 2009). On the contrary, the comparative biogeography

using both plant and animal data showed a clade of New

Guinea with the Bismarck Archipelago, the Solomon Islands

and northern Australia was sister to a clade of Southeast Asia,

Wallacea and Sunda, and clearly separated from the rest of the

West Pacific islands (New Caledonia, Vanuatu, Fiji, Tonga,

Samoa) (Ung & al., 2016). The Maesa phylogeny shows a dif-

ferent picture, with New Guinean taxa more closely related to

all West Pacific islands than the rest of Malesia. This reflects

the complex natural history of the region which needs more

studies from different perspectives to reveal evolutionary

and biogeographic patterns accurately.

The infrageneric classification proposed here is based on

phylogeny, and geographic distribution is one of the main dis-

tinguishing criteria of the subgenera. The African taxa are

clearly separated from the Asian taxa. However, the geograph-

ical history of the Malesian region is complex (Michaux,

2010; Lohman & al., 2011; Van Welzen & al., 2011; Ung

& al., 2016), and the position of Asian Maesa species shows

no defined boundaries within Wallacea and adjacent islands.

Species that are distributed in Wallacea (Sulawesi, Maluku,

Lesser Sunda Islands) are scattered in all three Asian-Pacif ic

clades, as are species from Sumatra, Java, Borneo and the

Philippines. Unfortunately, our samples included only a few

species from Wallacea, and more collections are needed to de-

termine the biogeographic history of this region. The

Philippines acted as a stepping stone for plant distribution

from west to east of Malesia in many taxa (e.g., Aglaia,Gru-

dinski & al., 2014;Begonia, Thomas & al., 2012;Cyrtandra,

Atkins & al., 2020). Our tree also shows this trend, with three

native scrambling species from the Philippines together with

scrambling taxa from Borneo forming a sister clade to the rest

of New Guinea and Pacific taxa.

Our recent taxonomic revision of the genus in New

Guinea used habit as the first character in the key and hypoth-

esized its value for infrageneric classification (Sumanon & al.,

submitted). The result here shows paraphyly of scrambling

Maesa (Fig. 1). The climbing life form appears to have

evolved independently in various plant groups e.g., Ficus L.

subg. Synoecia (Miq.) Miq. (Zhang & al., 2020) and

Trichomanes L. (Dubuisson & al., 2003). Although climbing

habit is an obvious character and practical to use in species

identification especially in a group with few distinctive char-

acters like Maesa, it cannot be used as a synapomorphy for de-

fining groups, even within a subgenus. In an evolutionary

perspective, scrambling habit may increase the ability of a

taxon to explore a new habitat and radiate (Gianoli, 2004;

Rowe & Speck, 2005; Rios & al., 2014). Darwin (1865)

hypothesized that this non self-supporting habit allowed

plants to economize their cost of constructing stems and invest

in forming a large and competitive leaf canopy. Lianas possess

a greater ratio of leaf mass to stem diameter than trees, indicat-

ing their biomass allocation strategy to reach and explore the

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Sumanon & al. •Phylogeny and classification of Maesa TAXON 00 (00) •1–20

canopy (Wyka & al., 2013). Interestingly, most Maesa scram-

blers found in the Papuanae clade have a restricted distribution

to a single island. This trait may relate to the ability to explore

and establish in a new environment. Ecological traits related to

scrambling form, as well as ancestral state reconstruction, will

be investigated in the further trait evolution studies we are

conducting in the genus.

Leaf margins have taxonomic value in the subgeneric clas-

sification, especially in Asian species. This character is used as

the secondary character to assign species that could not be sam-

pled in the recent analysis to each subgenus. Species with ser-

rate leaf margins are concentrated in Maesa subg. Indicae,

while those with entire leaf margins are in the other Asian sub-

genera. Toothed leaves were reported to be related to environ-

mental factors. For example, water availability could explain

the distribution of species with toothed leaves across

Australian subtropical rainforest (Royer & al., 2009). The ap-

pearance of leaf margins is linked with leaf thickness and vena-

tion: toothed margins with thin leaves and craspedodromous or

semicraspedodromous venation, and untoothed margins with

thick leaves and brachidodromous, eucamptodromous, or reti-

culodromous venation (Givnish & Kriebel, 2017). We have

also noticed this trend in Maesa and are currently working on

examining it in more detail for a trait evolution study. The dis-

tribution patterns of entire or non-entire leaf margins may be re-

lated to terrestrial biome types indicating biomechanics,

hydraulics, vein geometry, leaf expansion rate and bud packing

of the plants (Givnish & Kriebel, 2017). This character may link

to the environmental conditions of each geographical region,

and further biogeographic studies, together with other func-

tional traits, are needed to explore this idea in more detail.

Taxonomically complex groups. —There are two main

taxonomic questions about Maesa, concerning the number

of species and the range. First, most species, especially those

in the Malesia-Pacific regions, have a restricted distribution

to a single island. Does this pattern reflect the real evolution-

ary history of these taxa? Or is it because each local revision

of the genus was conducted by different taxonomists, and each

had different criteria to delimit species? We found that for

Pacific islands, species from each island mostly formed a

monophyletic clade (Fiji, Vanuatu and Tonga clades), sug-

gesting the consequence of allopatric speciation in Maesa

rather than bias of taxonomists. On the other hand, the species

from the Malesian islands are scattered in all three Asian and

Pacific clades, reflecting the complicated geological and spe-

cies dispersal history of this area.

Second, in each distribution region, there are species com-

plexes that need to be investigated with respect to species

boundaries. These complex species/species complexes show

morphological variation that lacks distinct features for species

delimitation, and taxonomists must apply a broad species con-

cept to these species, which usually leads to confusion. Accu-

rate species delimitation is essential in many areas of biology;

thus, one of our goals in this study was to determine the species

boundaries of Maesa species complexes. Maesa ramentacea is

a good example of how splitting a widely distributed species

with morphological variation makes species delimitation more

sensible. This name was once applied throughout Southeast

Asia to species with glabrous appearance and elliptic leaves

with entire margins. However, some specimens were wrongly

determined. Based on morphological characters, including

habit, leaf size and shape, and indumentum, together with eco-

logical requirements and distribution range, the M. ramentacea

complex was split into five species: M. ramentacea,

M. fraseriana,M. inculticola,M. malayana and M. sumatrana

(Utteridge, 2012,2021). Their positions in our phylogenetic

tree confirm that they are distinct species. Employing similar

molecular techniques with improved sampling, we may be able

to gain more resolution of the Maesa species complexes. In this

study, we focused on M. lanceolata from Africa, M. indica and

M. montana from continental Asia and M. bismarckiana and

M. haplobotrys from New Guinea. All except M. lanceolata

(LPP = 1) were not monophyletic.

In our revision of Maesa in New Guinea (Sumanon & al.,

submitted), four entities of M. bismarckiana were proposed as

artificial units to aid identification based on their variation in

leaf margin and distribution of hirsutellous (<0.05 mm long)

hair. Unfortunately, not all of the entities worked well in se-

quence recovery during our analysis; “M. bismarckiana 2”

and “M. bismarckiana 3”, which are provisionally placed in

the same entity “glabra”, with entire leaf margins and without

hairs, did not form a clade. “Maesa bismarckiana 1”is in en-

tity “serrata”, with papilliform teeth on the leaf margin, while

M. serpentinopicta was recognized as M. bismarckiana entity

“hirsutella”in Sumanon & al. (submitted). These latter two

accessions are grouped together, confirming the decision to

synonymize M. serpentinopicta under M. bismarckiana. All

accessions of M. bismarckiana are not monophyletic indicat-

ing that this and related species require further analysis and re-

vision. Maesa haplobotrys showed variation in leaf

morphology and it is very difficult to make a solid description

of the species. Accessions of M. haplobotrys do not form a

monophyletic clade, indicating the need to re-evaluate the

concept of this species.

In the Indicae clade, there are two complex species: Maesa

indica and M. montana. The tree shows a M. indica-M. tenera-

M. montana-M. perlaria complex (Fig. 1), which includes ac-

cessions from China, Japan, Hong Kong, Taiwan and

Thailand. Maesa indica from India (“M. indica 3”,“M. indica

5”) and Sri Lanka (“M. indica 1”) formed a clade separate from

the other M. indica accessions. Maesa laxa was once recog-

nized as M. indica in the Philippines after the examination of

M. indica collections from the entire distributional range failed

to reveal any satisfactory characters to distinguish M. indica

from M. laxa (Utteridge & Saunders, 2004), but two accessions

of this species formed a clade and were clearly separated from

the other M. indica. Thus, we reinstate M. laxa as a distinct

taxon. The same practice should be applied to Indian and East-

ern Asian M. indica. Consequently, the species concept of

widespread Asian species needs to be reconsidered.

The current phylogenetic study confirms that those com-

plex species need to be revised. However, our phylogenetic

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framework alone cannot provide sufficient information at

species rank, which may due to incomplete lineage sorting,

hybridization, intergenomic gene transfer, genome organiza-

tion, species demography, selection, genetic and geographic

structure (Naciri & Linder, 2015). Unsurprisingly, our dataset

lacks phylogenetic signal at shallower levels and cannot pro-

vide a basis for species delimitation in complex groups. An

extensive field sampling campaign covering the entire distri-

bution range and morphological variation, together with an in-

tegrated approach using multiple sources of molecular data,

population genetics and statistical analyses of morphological

traits, niche differentiation and potential reproductive isola-

tion, is needed to resolve species boundaries and provide un-

ambiguous taxonomic treatments of complex taxa (Flores-

Rentería & al., 2013; Medrano & al., 2014; Feng & al.,

2021; Lu & al., 2021). Unsupervised machine learning is also

an interesting approach for species delimitation and cluster

discovery, especially for taxa with few noticeable morpholog-

ical differences (Ezard & al., 2010). This method has been re-

ported for its potential to uncover or explore key features that

may have been overlooked due to human bias (Derkarabetian

& al., 2019; Saryan & al., 2020).

■TAXONOMIC TREATMENT

The phylogenetic analysis performed here allows us to pre-

sent a new infrageneric taxonomy of Maesa.Therearespecies

that we were unable to include in the analysis, but because of a

strong signal of geographic separation, we can assign them to a

subgenus based on their distribution and morphological charac-

ters, especially leaf morphology. Those species are marked with

an asterisk in the species lists of the subgenera. Some species

occurring in biogeographically ambiguous areas (Sulawesi,

Java, Lesser Sunda Islands, Sumatra, Borneo, Maluku) require

further study to confirm their affiliation with the subgenus.

Maesa Forssk., Fl. Aegypt.-Arab.: 66. 1775 –Type: Maesa

lanceolata Forssk.

Description. –Trees, shrubs or scramblers. Indumentum

of unicellular, unbranched hairs, either short and stiff, giving

a hirsutellous appearance, or longer and softer, giving a pilose

appearance, and circular to irregularly shaped peltate scales,

hairs and scales usually very dense on young parts when pre-

sent, or plants glabrous. Stipules absent. Leaves alternate, sim-

ple, chartaceous to coriaceous, lamina usually glabrous or

sparsely hairy and/or scaly, sometimes densely hairy, ovate

to elliptic to obovate, apex variable from retuse to acuminate,

usually acute to attenuate, base variable, cordate to attenuate

usually cuneate, margins entire to serrate; secondary veins

brochidodromus (when margins entire) or semicraspedodro-

mous (when margins serrulate or serrate), midrib usually im-

pressed adaxially and prominent abaxially, sometimes hairy

and/or scaly or glabrous; brown to black glandular lines usu-

ally visible on the lamina; petiolate, very rarely leaves subses-

sile, hairy and/or scaly or glabrous. Inflorescence axillary,

sometimes appearing terminal (in scrambling species due to

reduction in subtending leaves), in simple or compound ra-

cemes, hairy to glabrous; pedicellate, pedicels subtended by

a floral bract and with a pair of alternate to subopposite brac-

teoles. Flowers small, 4- or 5-merous, usually functionally

unisexual; sepals 4 or 5, fused, imbricate, usually with glandu-

lar lines, glabrous to hairy and/or scaly, margins entire, erose

or ciliate; petals white to cream, 4 or 5, fused at base, campan-

ulate or rarely urceolate, imbricate or quincuncial, usually

with glandular lines, glabrous, margins entire; stamens 4 or

5, adnate to corolla-tube and opposite the petal lobes, in-

cluded; anthers ovate or reniform; ovary half-inferior, style cy-

lindrical; stigma capitate or shortly 3- to 5-lobed; ovules

uniseriate or multiseriate. Fruit indehiscent, drupaceous with

a crustaceous endocarp and thin, fleshy mesocarp, globose

to subglobose, green ripening red, orange or black, reddish-

brown, brown to black when dry, often with glandular lines,

style and stigma often persistent.

Geographic distribution. –Asia, Australia, Polynesian is-

lands and Africa.

Species number. –Ca. 192.

1. Maesa Forssk. subg. Maesa

Description. –Trees or shrubs, rarely scramblers. Leaves

ovate, elliptic to lanceolate, occasionally oblanceolate, apex

acute to acuminate, occasionally obtuse, base rounded, truncate

or cuneate, margins entire, occasionally serrate. Inflorescences

axillary, compound racemes. Flowers 5-merous; bracteoles

free, subopposite; ovules multiseriate. (Fig. 2A,B)

Distribution. –Tropical Africa, Arabian Peninsula,

Madagascar.

Note. –This subgenus consists of African species with

multiseriate ovules. It includes the type species of Maesa,

M. lanceolata. The species is widespread throughout tropical

Africa, the Arabian Peninsula and Madagascar. It shows mor-

phological variation which causes difficulty in species delim-

itation, and the name M. lanceolata is usually applied in a

broad sense. Some taxa previously placed as synonyms of

M. lanceolata were sampled in this study which showed that

they are not grouped with M. lanceolata. Therefore, we have

reinstated these synonyms (M. angolensis,M. borjaeana,

M. rufescens) and are aware of that further changes may be

needed as more fieldwork and sampling become available

for detailed studies.

Species assigned (8 species). –Maesa angolensis Gilg,

M. borjaeana Henriq., M. kamerunensis Mez, M. kivuensis

Taton, M. lanceolata Forssk., M. nuda Hutch. & Dalziel,

M. rufescens A.DC., M. vestita Jacq.-Fél.*

2. Maesa subg. Indicae Sumanon, Eiserhardt & Utteridge,

subg. nov. –Type: Maesa indica (Roxb.) Sweet (≡Baeo-

botrys indica Roxb.).

Description. –Trees or shrubs, rarely scramblers. Leaves

elliptic, ovate to lanceolate, apex acuminate, base acute, ob-

tuse, rounded or cuneate, margins serrulate to serrate, rarely

entire. Inflorescences axillary, simple or compound racemes.

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Flowers 4- or 5-merous; bracteoles free, subopposite; ovules

multiseriate. (Fig. 2E)

Distribution. –Continental Asia, Japan, Taiwan, Thai-

Malay Peninsula, Borneo, Sumatra, Sulawesi, Java, and

Philippines.

Note. –This subgenus includes species of trees or shrubs

mainly from the Asian Continent (India, China, Indochina).

Leaves are usually elliptic, ovate to lanceolate with serrate

margins. No obovate or oblanceolate leaves are found in this

subgenus.

Maesa palauensis is included in this subgenus based on

our results; however, geographically, it would be more logical

to group with M. subg. Papuanae. Most members in this sub-

genus possesses serrate to serrulate leaf margins, while

M. palauensis is one of three species with entire leaf margins.

Without additional evidence, we accept the position of this

species in M. subg. Indicae, but note that further study is

needed to confirm the result.

Species assigned (92 species).–Maesa acuminatissima

Merr., M. ambigua C.Y.Wu & C.Chen*,M. andamanica Kurz,

M. argentea (Wall.) A.DC., M. argyrophylla K.Larsen &

C.M.Hu, M. arunachalensis G.S.Giri, S.K.Das & M.P.Nayar*,

M. augustini (Nakai) Tuyama*,M. balansae Mez, M. benga-

lensis Mez, M. blumei D.Don*,M. brachybotrya Miq.,

M. brevipaniculata (C.Y.Wu & C.Chen) Pipoly & C.Chen,

M. calophylla Pit., M. cambodiana C.M.Hu & J.E.Vidal,

M. cavinervis C.Chen*,M. chisia D.Don, M. clementis

Merr.*,M. conferta Merr.*,M. confusa (C.M.Hu) Pipoly &

C.Chen*,M. consanguinea Merr. *,M. costulata Miq.*,

M. davaensis Quisumb.*,M. densistriata C.Chen & C.M.

Hu*,M. denticulata Mez, M. dubia (Wall.) A.DC.*,

M. ferruginea Merr.*,M. forbesii Mez*,M. glomerata K.Lar-

sen & C.M.Hu*,M. grandiflora Mez*,M. grandifolia Miq.*,

M. haenkeana Mez, M. hirtella Miq.*,M. hupehensis Rehder,

M. ilicifolia Ridl.*,M. indica (Roxb.) Sweet, M. insignis

Chun*,M. integrifolia Ridl., M. japonica (Thunb.) Moritzi

ex Zoll., M. junghuhniana Scheff., M. kanjilalii Majumdar

& G.S.Giri*,M. kerrii C.M.Hu & J.E.Vidal*,M. kurzii Mez,

M. laevis C.M.Hu & J.E.Vidal*,M. lanyuensis Yuen

P.Yang*,M. latifolia A.DC.*,M. laxa Mez, M. laxiflora

Pit., M. leucocarpa Blume ex Scheff.*,M. lineolata

H.R.Fletcher, M. longilanceolata C.Chen*,M. macilenta

E.Walker*,M. macilentoides C.Chen*,M. macrocarpa

Scheff., M. macrophylla (Wall.) A.DC., M. manillensis Mez*,

M. manipurensis Mez*,M. marioniae Merr.*,M. martiana

Mez, M. maxima (C.B.Clarke) Mez, M. membranacea A.DC.,

M. montana A.DC., M. muscosa Kurz*,M. naumanniana

Mez*,M. nayarii G.S.Giri & S.K.Das*,M. ovocarpa Ridl.*,

M. pahangiana King & Gamble, M. palauensis Mez,

M. paniculata A.DC., M. parviflora Scheff.*,M. parvifolia

Aug.DC., M. perlaria (Lour.) Merr., M. permollis Kurz,

M. pilosa Utteridge, M. pipericarpa Mez*,M. pisocarpa

Blume ex Scheff., M. platyphylla Elmer*,M. populifolia Mez*,

M. reticulata C.Y.Wu*,M. rugosa C.B.Clarke, M. salicifolia

E.Walker, M. stonei Utteridge & R.M.K.Saunders*,M. striata

Mez*,M. striatocarpa C.Chen*,M. subdendata A.DC.*,

M. tenera Mez, M. tenuifolia Mez*,M. truncata Sastry*,M. ve-

lutina Mez*,M. villosa Mez*,M. warburgii Mez, M. wardii

M.P.Nayar & G.S.Giri*,M. ziroensis G.S.Giri & G.D.Pal*.

3. Maesa subg. Monotaxis Mez in Engler, Pflanzenr. IV.

236 (Heft 9): 23. 1902 –Type (designated here): Maesa

alnifolia Harv.

Description. –Trees or shrubs. Leaves obovate to elliptic,

apex obtuse to acute, occasionally acuminate, base cuneate,

margins serrate. Inflorescences axillary, simple racemes.

Flowers 5-merous; bracteoles free, subopposite; ovules uni-

seriate. (Fig. 2C)

Distribution. –Tropical Africa.

Note. –This subgenus includes African species with ob-

ovate to elliptic leaves with serrate margins, and simple race-

mose inflorescences in an axillary position. The unique

character among all subgenera is ovules arranged in one row.

Mez (1902) proposed a subgeneric classification of

Maesa and classified species with uniseriate ovules in

M. subg. Monotaxis. However, he did not specify a type for

the subgenus. We assign M. alnifolia as the type of the subge-

nus because of its easy-to-recognize morphological features.

Species assigned (2 species).–Maesa alnifolia Harv.,

M. welwitschii Gilg.

4. Maesa subg. Papuanae Sumanon, Eiserhardt & Utteridge,

subg. nov. –Type: Maesa papuana Warb.

Description. –Trees, shrubs or scramblers. Leaves ellip-

tic, ovate, obovate, oblanceolate to lanceolate, apex rounded,

obtuse, acute, acuminate to attenuate, base rounded, obtuse,

cuneate, occasionally cordate, margins entire, serrulate or ser-

rate. Inflorescences axillary, simple or compound racemes.

Flowers 4- or 5-merous; bracteoles free or fused, subopposite

or alternate; ovules multiseriate. (Fig. 2F)

Distribution. –Borneo, Sulawesi, Maluku, Palau,

Philippines, New Guinea, Caroline Islands, Solomon Islands,

Vanuatu, New Caledonia, Fiji, Tonga and Samoa.

Note. –This subgenus comprises all species from the

Papua-Pacific region, scrambler species from the Philippines

and Borneo and one species from Maluku. It is a large subge-

nus with most members being island endemics. Three samples

from Sulawesi are included in this subgenus: one determined

as Maesa tetrandra and two unidentified.

The morphology of this subgenus is diverse, both in terms

of vegetative and reproductive parts. Leaves can be of any

shape, with different apices, bases and margins; the inflores-

cence type is also variable, as are floral characters. We note

that fused bracteoles are found only in species included in this

subgenus.

The native range of Maesa rubiginosa is Maluku, the is-

lands of which are theoretically part of Wallacea. In Van

Welzen & al. (2011), Wallacea was divided into a western

(Java, Philippines, Lesser Sunda Islands) and an eastern com-

ponent (Sulawesi, Moluccas [Maluku]). Their cluster analysis

(UPGMA) and principal component analysis of 100 subma-

trices showed the flora of Sulawesi and Maluku was more

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TAXON 00 (00) •1–20 Sumanon & al. •Phylogeny and classification of Maesa

closely related to the Australian-Papuan region. In the protolo-

gue (Scheffer, 1867), M. rubiginosa was noted to be similar to

M. mollis (Blume) A.DC., a species which is now a synonym

of M. tetrandra. A distinct difference between these two spe-

cies is the leaf margin: entire in M. tetrandra and serrate in

M. rubiginosa. Maesa rubiginosa is sister to all M. tetrandra;

therefore, the inclusion of this species in M. subg. Papuanae is

reasonable.

Species assigned (74 species).–Maesa ambrymensis

Guillaumin, M. amplexicaulis Utteridge*,M. aneiteensis

Mez, M. angustibracteolata Sumanon & Utteridge,

M. aubertii Guillaumin, M. aurulenta Sumanon & Utteridge,

M. banksiana Guillaumin, M. beamanii Utteridge,

M. begonifolia Sumanon & Utteridge*,M. bennettii Mez*,

M. bismarckiana Mez, M. brassii Sumanon & Utteridge*,

M. brevipedicellata Sumanon & Utteridge, M. calcarea Sleu-

mer, M. carolinensis Mez, M. cauliflora Kaneh. & Hatus.,

M. corneri Sleumer, M. corylifolia A.Gray, M. cumingii

Mez, M. decipiens Utteridge, M. dependens F.Muell.,

M. edulis C.T.White, M. efatensis Guillaumin*,M. era-

mangensis Mez, M. fruticosa Gibbs, M. gaudichaudii

A.DC., M. gracilis Utteridge*,M. haplobotrys F.Muell.,

M. hooglandii Sleumer*,M. insularis Gillespie, M. jaffrei

M.Schmid*,M. lobuligera Mez, M. loloruensis Sleumer*,

M. loranthifolia Mez, M. lorentziana Mez*,M. macrothyrsa

Miq., M. megalobotrya Merr.*,M. megaphylla Merr.*,

M. megistophylla Utteridge*,M. montis-wilhelmi P.Royen,

M. muelleri Mez, M. nemoralis (J.R.Forst. & G.Forst.)

A.DC., M. novocaledonica Mez, M. novoguineensis Scheff.,

M. oblanceolatifolia Sumanon & Utteridge*,M. papuana

Warb., M. pentecostes Guillaumin*,M. persicifolia A.Gray,

M. pickeringii A.Gray, M. pilosopapuana Sumanon & Utter-

idge, M. procumbens Utteridge, M. prolatifructa Sumanon

& Utteridge*,M. protracta F.Muell., M. purpureohirsuta

Kaneh. & Hatus., M. pusilliflora Sumanon & Utteridge,

M. reflexa Utteridge & R.M.K.Saunders, M. regia Sleumer,

M. reinwardtii Blume ex Scheff.*,M. rheophytica Sleumer,

M. robinsonii Merr.*,M. rubiginosa Blume ex Scheff.,

M. ruficaulis S.Moore, M. rufovillosa Mez, M. samoana Mez,

M. sayersii Sleumer, M. serratifolia Sumanon & Utteridge,

M. sleumerii Sumanon & Utteridge, M. spectabilis Sleumer,

M. tabacifolia Mez, M. tagulensis Sumanon & Utteridge,

M. tetrandra (Roxb.) A.DC., M. tongensis Mez, M. vitiensis

Seem., M. walkeri Fosberg & Sachet*.

5. Maesa subg. Ramentaceae Sumanon, Eiserhardt & Utter-

idge, subg. nov. –Type: Maesa ramentacea (Roxb.)

A.DC. (≡Baeobotrys ramentacea Roxb.).

Description. –Trees, shrubs or scramblers. Leaves ovate,

elliptic to lanceolate, apex attenuate to acuminate, base

rounded, margins entire, sometimes serrulate to serrate. Inflo-

rescences axillary or terminal, simple to compound racemes.

Flowers 4- or 5-merous; bracteoles free, subopposite; ovules

multiseriate. (Fig. 2D)

Distribution. –Continental Asia, Thai-Malay Peninsula,

Borneo, Sumatra and Java.

Note. –This subgenus includes Asian species mainly dis-

tributed in Sundaland (Malay Peninsula, Borneo, Sumatra,

Java). There is one species (Maesa tomentella) distributed in

Indochina and another one (M. ramentacea) broadly distrib-

uted in southern China to Indochina and the Malay Peninsula.

In addition to its distribution, the key features of this subgenus

are leaves that are usually ovate to elliptic with an acuminate

or tapering attenuate apex, rounded base and entire margins.

Species assigned (16 species).–Maesa arborea Ridl.*,

M. cordifolia Miq., M. decidua Philipson, M. fraseriana

Utteridge, M. impressinervis King & Gamble, M. inculticola

Utteridge, M. lancifolia Ridl.*,M. leptobotrya Hance,

M. malayana Utteridge, M. oligotricha Merr., M. procera

B.C.Stone, M. pulchella Fawc.*,M. ramentacea (Roxb.)

A.DC., M. sumatrana Scheff., M. tomentella Mez,

M. virgata (Blume) A.DC.*

■CONCLUSION

With the phylogenomic framework presented here, we

now have evidence to propose the f irst comprehensive system-

atic arrangement of Maesa, the “vast genus”with few distinc-

tive characters. Our species-level tree shows a strong signal of

geographical distribution which we utilize for the new infrage-

neric classification with five subgenera. We have found some

useful morphological characters; however, they are few, and

we need to undertake further work to identify a larger number

of morphological characters to delimit each subgenus. In addi-

tion, it is difficult to assign many unsampled Wallacean taxa

to a subgenus based on geographic distribution alone, as there

are no defined boundaries within Wallacea and adjacent is-

lands. The phylogenetic tree obtained here confirms that many

species complexes/complex species require revision, and

modern analysis methods, e.g., unsupervised machine learn-

ing, may provide the means to disentangle the complexity of

such problematic taxa. This study also provides fundamental

results for further detailed studies to test evolutionary hypoth-

eses for a taxon with high species diversity but few marked re-

productive differences such as Maesa, and unlocks the

potential of this complicated and often overlooked genus for

studies of biogeography, trait evolution and diversification.

■AUTHOR CONTRIBUTIONS

PS: designed the study, examined and sampled specimens, gener-

ated DNA sequences, conducted phylogenetic analyses, made taxo-

nomic decisions and prepared the manuscript. TMAU: developed the

original research topic, examined and sampled specimens, determined

and confirmed specimens, made taxonomic decisions, supervised the

study with respect to systematic and nomenclatural issues and prepared

the manuscript. HB: supervised the study and commented on the man-

uscript. WLE: developed the original research topic, designed the study,

made suggestions on methods, provided some scripts for phylogenetic

analyses, supervised the study with respect to phylogenetic and system-

atic issues, provided laboratory and technical facilities and prepared the

14 Version of Record

Sumanon & al. •Phylogeny and classification of Maesa TAXON 00 (00) •1–20

manuscript. —PS, https://orcid.org/0000-0001-7247-8255;TMAU,

https://orcid.org/0000-0003-2823-0337;HB,https://orcid.org/0000-

0002-7101-7120;WLE,https://orcid.org/0000-0002-8136-5233

■ACKNOWLEDGMENTS

PS would like to express gratitude to the Royal Thai Government

Scholarship for financial support throughout her Ph.D. study and to cu-

rators of AAU, BKF, FU, and K, who kindly providedleaf materials for

the analysis. The authors would like to thank all photographers (Bart

Wursten, Mark Hyde, Garth Aiston, Theerawat Thananthaisong), who

provided great pictures of Maesa used in this manuscript. Thanks to

Helen Hartley and Rafaël Govaerts at Kew for nomenclatural advice.

This study was supported by grants from the Aarhus University Re-

search Foundation and VILLUM FONDEN (grant 00025354) to WLE.

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Appendix 1. Details of specimens used in this study with assigned subgenus.

All read sequences used were newly generated and deposited on Sequence Read Archive (SRA: https://www.ncbi.nlm.nih.gov/sra) data of NCBI server.

Data presented in the following format: taxon name, tip label in the phylogeny, country of origin: collectorand collector number (herbarium code), SRA acces-

sion number, subgenus assigned in this study.

Ardisia amabilis Stapf, Ardisia amabilis, Malaysia: Beaman 8676a (K), SRR17422211, outgroup; Ardisia celebica Scheff., Ardisia celebica, Indonesia: Hicks

199 (K), SRR17422210, outgroup; Ardisia copelandii Mez, Ardisia copelandii, Brunei: Bin Hj. Shahbud BRUN18926 (K), SRR17422032, outgroup; Ardisia

diversilimba Merr., Ardisia diversilimba, Brunei: Said 15798 (K), SRR17422021, outgroup; Ardisia elmeri Mez, Ardisia elmeri, Philippines: Stone & al.

PPI460 (K), SRR17422117, outgroup; Ardisia guianensis (Aubl.) Mez, Ardisia guianensis, Guyana: Pipoly 8066 (K), SRR17422106, outgroup; Ardisia lan-

ceolata Roxb., Ardisia lanceolata, Indonesia: Chruch 302 (K), SRR17422095, outgroup; Ardisia oocarpa Stapf, Ardisia oocarpa, Malaysia: Bakia 44 (K),

SRR17422058, outgroup; Ardisia steiranthera B.C.Stone, Ardisia steiranthera, Brunei: Ashton BRUN4 (K), SRR17422047, outgroup; Ardisia sumatrana

Miq., Ardisia sumatrana, Indonesia: Lee & al. SL679 (K), SRR17422155, outgroup; Ardisia tinifolia Sw., Ardisia tinifolia, Jamaica: Loveless 2437 (K),

SRR17422209, outgroup; Maesa acuminatissima Merr., Maesa acuminatissima 1, Vietnam: Du HNK3167 (K), SRR17422198, Indicae;Maesa acuminatis-

sima Merr., Maesa acuminatissima 2, China: Tsang & Fung 568 (K), SRR17422187, Indicae;Maesa alnifolia Harv., Maesa alnifolia, South Africa: Hilliard

& Burtt 16756 (K), SRR17422136, Monotaxis;Maesa ambrymensis Guillaumin, Maesa ambrymensis, Vanuatu: Wheatley 665 (K), SRR17422125, Papuanae;

Maesa andamanica Kurz, Maesa andamanica, India: Parkinson 353 (K), SRR17422087, Indicae;Maesa aneiteensis Mez, Maesa aneiteensis, Vanuatu: Chew

RSNH341 (K), SRR17422076, Papuanae;Maesa angolensis Gilg, Maesa angolensis, Angola: Welw 4798 (K), SRR17422184, Maesa;Maesa angustibracteo-

lata Sumanon & Utteridge, Maesa angustibracteolata, Papua New Guinea: Hartley TGH10713 (K), SRR17422173, Papuanae;Maesa argentea (Wall.) A.DC.,

Maesa argentea 1, China: Green 2104 (K), SRR17422162, Indicae;Maesa argentea (Wall.) A.DC., Maesa argentea 2, Cultivated: 40-60.04002 (K),

SRR17422031, Indicae;Maesa argyrophylla K.Larsen & C.M.Hu, Maesa argyrophylla, Thailand: KKU10919 (AAU), SRR17422030, Indicae;Maesa aubertii

Guillaumin, Maesa aubertii, Vanuatu: Haevermans 390 (K), SRR17422029, Papuanae;Maesa aurulenta Sumanon & Utteridge, Maesa aurulenta, Papua New

Guinea: Kanis 1242 (K), SRR17422028, Papuanae;Maesa balansae Mez, Maesa balansae, China: Chow & al. 78329 (K), SRR17422027, Indicae;Maesa

banksiana Guillaumin, Maesa banksiana, Vanuatu: Wheatley 394 (K), SRR17422026, Papuanae;Maesa beamanii Utteridge, Maesa beamanii, Indonesia:

Utteridge 423 (K), SRR17422025, Papuanae;Maesa bengalensis Mez, Maesa bengalensis, India: Koelz 26425 (K), SRR17422024, Indicae;Maesa bismar-

ckiana Mez, Maesa bismarckiana 1, Indonesia: Utteridge 222 (K), SRR17422022, Papuanae;Maesa bismarckiana Mez, Maesa bismarckiana 2, Papua

New Guinea: Hoogland 9452 (K), SRR17422023, Papuanae;Maesa bismarckiana Mez, Maesa bismarckiana 3, Papua New Guinea: Hartley TGH12070

(K), SRR17422020, Papuanae;Maesa bismarckiana Mez, Maesa bismarckiana 4[M. serpentinopicta], Papua New Guinea: Vinas & Lelean LAE59324 (K),

SRR17422073, Papuanae;Maesa borjaeana Henriq., Maesa borjaeana, Equatorial Guinea: Casas 11535 (K), SRR17422019, Maesa;Maesa brachybotrya

Miq., Maesa brachybotrya, Indonesia: Junghun 245 (K), SRR17422018, Indicae;Maesa brevipaniculata (C.Y.Wu & C.Chen) Pipoly & C.Chen, Maesa brevi-

paniculata, China: Qin 890316 (K), SRR17422140, Indicae;Maesa brevipedicellata Sumanon & Utteridge, Maesa brevipedicellata 1, Papua New Guinea:

Kairo 51 (K), SRR17422017, Papuanae;Maesa brevipedicellata Sumanon & Utteridge, Maesa brevipedicellata 2, Papua New Guinea: Lelean 46396 (K),

SRR17422016, Papuanae;Maesa brevipedicellata Sumanon & Utteridge, Maesa brevipedicellata 3, Papua New Guinea: Clemens 5205 (K), SRR17422015,

Papuanae;Maesa calcarea Sleumer, Maesa calcarea, Indonesia: Vink BW15248 (K), SRR17422014, Papuanae;Maesa calophylla Pit., Maesa calophylla

1, Vietnam: Chevalier 36721 (K), SRR17422013, Indicae;Maesa calophylla Pit., Maesa calophylla 2, Vietnam: Toyama & al. 2403 (FU), SRR17422012, In-

dicae;Maesa cambodiana C.M.Hu & J.E.Vidal, Maesa cambodiana, Cambodia: Khou 36 (K), SRR17422104, Indicae;Maesa carolinensis Mez, Maesa ca-

rolinensis 1, Micronesia: Stone 5320 (K), SRR17422118, Papuanae;Maesa carolinensis Mez, Maesa carolinensis 2, Micronesia: Ledermann 13588 (K),

SRR17422116, Papuanae;Maesa cauliflora Kaneh. & Hatus., Maesa cauliflora, Papua New Guinea: Streimann LAE52965 (K), SRR17422115, Papuanae;

Maesa chisia D.Don, Maesa chisia, Bhutan: Grierson & Long 3021 (K), SRR17422114, Indicae;Maesa cordifolia Miq., Maesa cordifolia, Indonesia: Meijer

7622 (K), SRR17422113, Ramentaceae;Maesa corneri Sleumer, Maesa corneri, Papua New Guinea: Schodde 3879 (K), SRR17422112, Papuanae;Maesa

corylifolia A.Gray, Maesa corylifolia 1, Fiji: Smith 5587 (K), SRR17422111, Papuanae;Maesa corylifolia A.Gray, Maesa corylifolia 2, Fiji: Greenwood

896 (K), SRR17422110, Papuanae;Maesa cumingii Mez, Maesa cumingii, Philippines: Argent & al. 99255 (K), SRR17422109, Papuanae;Maesa decidua

Philipson, Maesa decidua, Malaysia: Clemens & Clemens 50933 (K), SRR17422108, Ramentaceae;Maesa decipiens Utteridge, Maesa decipiens,

Indonesia: Kasmin 70 (K), SRR17422107, Papuanae;Maesa denticulata Mez, Maesa denticulata, Malaysia: Utteridge 483 (K), SRR17422105, Indicae;

Maesa dependens F.Muell., Maesa dependens, Australia: Gray 20269V (K), SRR17422103, Papuanae;Maesa edulis C.T.White, Maesa edulis,

Solomon Islands: Regalado & Sirikolo 700 (K), SRR17422102, Papuanae;Maesa eramangensis Mez, Maesa eramangensis, Vanuatu: Halle RSNH6427

(K), SRR17422100, Papuanae;Maesa fraseriana Utteridge, Maesa fraseriana, Malaysia: Latiff 4105 (K), SRR17422099, Ramentaceae;Maesa fruticosa

Gibbs, Maesa fruticosa, Indonesia: Gibbs 5579 (K), SRR17422098, Papuanae;Maesa gaudichaudii A.DC., Maesa gaudichaudii, Philippines: Reynoso

& al. PPI17170 (K), SRR17422097, Papuanae;Maesa haplobotrys F.Muell., Maesa haplobotrys 1, Papua New Guinea: Takeuchi 23191 (K),

SRR17422064, Papuanae;Maesa haplobotrys F.Muell., Maesa haplobotrys 2, Papua New Guinea: Takeuchi 15238 (K), SRR17422065, Papuanae;Maesa

haplobotrys F.Muell., Maesa haplobotrys 3, Papua New Guinea: Katik LAE74925 (K), SRR17422094, Papuanae;Maesa haplobotrys F.Muell., Maesa haplo-

botrys 4, Papua New Guinea: Pullen 6968 (K), SRR17422096, Papuanae;Maesa haplobotrys F.Muell., Maesa haplobotrys 6, Papua New Guinea: Brass 28299

(K), SRR17422093, Papuanae;Maesa haplobotrys F.Muell., Maesa haplobotrys 7, Papua New Guinea: Hoogland 4440 (K), SRR17422091, Papuanae;Maesa

hupehensis Rehder, Maesa hupehensis, China: Farges 1239 (K), SRR17422061, Indicae;Maesa impressinervis King & Gamble, Maesa impressinervis,

Malaysia: Imin FRI76055 (K), SRR17422060, Ramentaceae;Maesa inculticola Utteridge, Maesa inculticola, Malaysia: George S.40448 (K),

SRR17422059, Ramentaceae;Maesa indica (Roxb.) Sweet, Maesa indica 1, Sri Lanka: Weerasooriya & Samarasinghe 614 (K), SRR17422056, Indicae;

Maesa indica (Roxb.) Sweet, Maesa indica 2, Malaysia: Soepadmo & Mahmud 1119 (K), SRR17422057, Indicae;Maesa indica (Roxb.) Sweet, Maesa indica

3, India: Oates 45 (K), SRR17422055, Indicae;Maesa indica (Roxb.) Sweet, Maesa indica 4[M. elongata], India: Tessier-Tandell 76 (K), SRR17422101,

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Appendix 1. Continued.

Indicae;Maesa indica (Roxb.) Sweet, Maesa indica 5[M. perrottetiana], India: Klackenberg & Lundin 26 (K), SRR17422134, Indicae;Maesa indica var. wigh-

tiana A.DC., Maesa indica var. wightiana, Indonesia: Teysmann7618 (K), SRR17422054, Indicae;Maesa insularis Gillespie, Maesa insularis, Fiji: Smith 8476

(K), SRR17422053, Papuanae;Maesa integrifolia Ridl., Maesa integrifolia, Thailand: Kloss 6738 (K), SRR17422052, Indicae;Maesa japonica (Thunb.) Mo-

ritzi ex Zoll., Maesa japonica 1, China: Xiao 3947 (K), SRR17422051,Indicae;Maesa japonica (Thunb.) Moritzi ex Zoll., Maesa japonica 2, Japan: Togashi 527

(K), SRR17422050, Indicae;Maesa junghuhniana Scheff., Maesa junghuhniana, Indonesia: Maduarta IMM100 (K), SRR17422049, Indicae;Maesa kameru-

nensis Mez, Maesa kamerunensis, Cameroon: Cheek 12366 (K), SRR17422048, Maesa;Maesa kivuensis Taton, Maesa kivuensis, Zaire: Leonard 3806 (K),

SRR17422046, Maesa;Maesa kurzii Mez, Maesa kurzii, India: Tessier-Tandell 105 (K), SRR17422045, Indicae;Maesa lanceolata Forssk., Maesa lanceolata

1, Madagascar: Chase 34468 (K), SRR17422043, Maesa;Maesa lanceolata Forssk., Maesa lanceolata 2, Madagascar: Anderberg & al. 25 (K), SRR17422044,

Maesa;Maesa lanceolata Forssk., Maesa lanceolata 3, Tanzania: Marshall 1426 (K), SRR17422042, Maesa;Maesa lanceolata Forssk., Maesa lanceolata

4, Yemen: Radcliff-Smith & Henchie 4724 (K), SRR17422041 Maesa;Maesa laxa Mez, Maesa laxa 1, Philippines: Jacobs 7613 (K), SRR17422040, Indicae;

Maesa laxa Mez, Maesa laxa 2, Philippines: McGregor 19831 (K), SRR17422039, Indicae;Maesa laxiflora Pit., Maesa laxiflora 1, China: Lei 393 (K),

SRR17422156, Indicae;Maesa laxiflora Pit., Maesa laxiflora 2, Vietnam: Clemens & Clemens 3793 (K), SRR17422158, Indicae;Maesa leptobotrya Hance,

Maesa leptobotrya 1, Malaysia: Imin FRI71532 (K), SRR17422154, Ramentaceae;Maesa leptobotrya Hance, Maesa leptobotrya 2, Malaysia: Emiza FRI55051

(K), SRR17422153, Ramentaceae;Maesa lineolata H.R.Fletcher, Maesa lineolata, Thailand: Kerr 10496 (K), SRR17422152, Indicae;Maesa lobuligera Mez,

Maesa lobuligera, Philippines: Ridsdale SMHI1766 (K), SRR17422151, Papuanae;Maesa loranthifolia Mez, Maesa loranthifolia, Papua New Guinea: Coode

& Katik NGF29958 (K), SRR17422150, Papuanae;Maesa macrocarpa Scheff., Maesa macrocarpa, Indonesia: Gregson & Bala Ola 55 (K), SRR17422149,

Indicae;Maesa macrophylla (Wall.) A.DC., Maesa macrophylla, Bhutan: Grierson & Long 2949 (K), SRR17422148, Indicae;Maesa macrothyrsa Miq.,

Maesa macrothyrsa 1, Malaysia: Tadong 326 (K), SRR17422147, Papuanae;Maesa macrothyrsa Miq., Maesa macrothyrsa 2, Malaysia: Sibil 130 (K),

SRR17422146, Papuanae;Maesa malayana Utteridge, Maesa malayana, Malaysia: Maxwell 78203 (AAU), SRR17422145, Ramentaceae;Maesa martiana

Mez, Maesa martiana, India: Tessier-Tandell 87 (K), SRR17422208, Indicae;Maesa maxima (C.B.Clarke) Mez, Maesa maxima, India: Simons s.n. (K),

SRR17422207, Indicae;Maesa membranacea A.DC., Maesa membranacea, China: Chun & Tso 43942 (K), SRR17422206, Indicae;Maesa montana

A.DC., Maesa montana 1, China (cultivated): Chase 17577 (K), SRR17422203, Indicae;Maesa montana A.DC., Maesa montana 2, China: Qin & al.

890251 (K), SRR17422202, Indicae;Maesa montana A.DC., Maesa montana 3, Bhutan: Grierson & Long 1423 (K), SRR17422200, Indicae;Maesa montana

A.DC., Maesa montana 4, Thailand: Geesink & al. 6987 (K), SRR17422199, Indicae;Maesa montana A.DC., Maesa montana 5, Thailand: T3585 (FU),

SRR17422201, Indicae;Maesa montana A.DC., Maesa montana 6[M. henryi], China: 425-78-04477 (K), SRR17422062, Indicae;Maesa montis-wilhelmi

P.Royen, Maesa montis-wilhelmi 1, Papua New Guinea: Millar & Sayers NGF23679 (K), SRR17422197, Papuanae;Maesa montis-wilhelmi P.Royen, Maesa

montis-wilhelmi 2, Papua New Guinea: Hoogland 9540 (K), SRR17422196, Papuanae;Maesa muelleri Mez, Maesa muelleri, Australia: Halford Q683 (K),

SRR17422195, Papuanae;Maesa nemoralis (J.R.Forst. & G.Forst.) A.DC., Maesa nemoralis 1, Vanuatu: Curry 1027 (K), SRR17422194, Papuanae;Maesa

nemoralis (J.R.Forst. & G.Forst.) A.DC., Maesa nemoralis 2, Vanuatu: Gowers NH165 (K), SRR17422193, Papuanae;Maesa novocaledonica Mez, Maesa

novocaledonica, New Caledonia: Tronchet 362 (K), SRR17422192, Papuanae;Maesa novoguineensis Scheff., Maesa novoguineensis, Indonesia: Davis 612

(K), SRR17422191, Papuanae;Maesa nuda Hutch. & Dalziel, Maesa nuda, Guinea: Farmar 324 (K), SRR17422190, Maesa;Maesa oligotricha Merr., Maesa

oligotricha, Indonesia: Davies 2000-016 (K), SRR17422189, Ramentaceae;Maesa pahangiana King & Gamble, Maesa pahangiana, Malaysia: Whitmore

FRI15778 (K), SRR17422188, Indicae;Maesa palauensis Mez, Maesa palauensis, Palau: Takamatsu 1764 (K), SRR17422186, Indicae;Maesa paniculata

A.DC., Maesa paniculata, Thailand: Middleton & al. 1443 (K), SRR17422185, Indicae;Maesa papuana Warb., Maesa papuana 1, Papua New Guinea: Takeu-

chi 7425 (K), SRR17422143, Papuanae;Maesa papuana Warb., Maesa papuana 2, Papua New Guinea: Gideon LAE57562 (K), SRR17422144, Papuanae;

Maesa parvifolia Aug.DC., Maesa parvifolia 1, China: Lei 354 (K), SRR17422141, Indicae;Maesa parvifolia Aug.DC., Maesa parvifolia 2, Vietnam: Balansa

2998 (K), SRR17422142, Indicae;Maesa perlaria (Lour.) Merr., Maesa perlaria 1, China: Hu & But 23853 (K), SRR17422139, Indicae;Maesa perlaria (Lour.)

Merr., Maesa perlaria 2, Hong Kong (cultivated): 438-60.43801 (K), SRR17422138, Indicae;Maesa perlaria var. formosana (Mez) Yuen P.Yang, Maesa per-

laria var. formosana, Japan: Yasuda 2339 (K), SRR17422204, Indicae;Maesa permollis Kurz, Maesa permollis 1, India: Burkill 36707 (K), SRR17422205, In-

dica;Maesa permollis Kurz, Maesa permollis 2, Thailand: Suddee 5498 (BKF), SRR17422137, Indicae;Maesa permollis var. effusa Walker, Maesa permollis

var. effusa, China: Forrest 12143 (K), SRR17422135, Indicae;Maesa persicifolia A.Gray, Maesa persicifolia, Fiji: Melville 71.1003 (K), SRR17422133, Papua-

nae;Maesa pickeringii A.Gray, Maesa pickeringii, Fiji: Vaughan 3208 (K), SRR17422132, Papuanae;Maesa pilosa Utteridge, Maesa pilosa, Malaysia: Paie

S16394 (K), SRR17422131, Indicae;Maesa pilosopapuana Sumanon & Utteridge, Maesa pilosopapuana, Papua New Guinea: Galore & Vandenberg

NGF41043 (K), SRR17422066, Papuanae;Maesa pisocarpa Blume ex Scheff., Maesa pisocarpa, Indonesia: Wen 10191 (K), SRR17422130, Indicae;Maesa

procera B.C.Stone, Maesa procera, Malaysia: Madani & Pereira SAN140086 (K), SRR17422129, Ramentaceae;Maesa procumbens Utteridge, Maesa procum-

bens, Indonesia: Utteridge 164 (K), SRR17422128, Papuanae;Maesa protractaF.Muell., Maesa protracta, Papua New Guinea: Sands1403 (K), SRR17422127,

Papuanae;Maesa purpureohirsuta Kaneh. & Hatus., Maesa purpureohirsuta, Indonesia: van Royen & Sleumer 7096 (K), SRR17422126, Papuanae;Maesa

pusilliflora Sumanon & Utteridge, Maesa pusilliflora, Papua New Guinea: Takeuchi 4645 (K), SRR17422124, Papuanae;Maesa ramentacea (Roxb.) A.

DC., Maesa ramentacea 1, Cambodia: Cheng & al. CL1169 (K), SRR17422123, Ramentaceae;Maesa ramentacea (Roxb.) A.DC., Maesa ramentacea 2, Viet-

nam: Du & al. HNK2203 (K), SRR17422122, Ramentaceae;Maesa reflexa Utteridge & R.M.K.Saunders, Maesa reflexa, Philippines: Ramos & Edano 38960

(K), SRR17422121, Papuanae;Maesa regia Sleumer, Maesa regia, Solomon Islands: Whitmore 6152 (K), SRR17422120, Papuanae;Maesa rheophytica Sleu-

mer, Maesa rheophytica, Indonesia: Arifiani 763 (K), SRR17422119, Papuanae;Maesa rubiginosa Blume ex Scheff., Maesa rubiginosa, Indonesia: Ramlanto

944 (K), SRR17422092, Papuanae;Maesa rufescens A.DC., Maesa rufescens, Guinea: Laws 53 (K), SRR17422090, Maesa;Maesa ruficaulis S.Moore, Maesa

ruficaulis 1, Indonesia: Utteridge 92 (K), SRR17422088, Papuanae;Maesa ruficaulis S.Moore, Maesa ruficaulis 2, Indonesia: Dransfield 7697 (K),

SRR17422089, Papuanae;Maesa ruficaulis S.Moore, Maesa ruficaulis 3, Indonesia: Barker 38 (K), SRR17422086, Papuanae;Maesa rufovillosa Mez, Maesa

rufovillosa 1, Papua New Guinea: Takeuchi 13091-A (K), SRR17422083, Papuanae;Maesa rufovillosa Mez, Maesa rufovillosa 2, Solomon Islands: Gafui & al.

BSIP17308 (K), SRR17422085, Papuanae;Maesa rufovillosa Mez, Maesa rufovillosa 3, Papua New Guinea: Ridsdale NGF33953 (K), SRR17422082, Papua-

nae;Maesa rufovillosa Mez, Maesa rufovillosa 4, Papua New Guinea: Gillison NGF25037 (K), SRR17422084, Papuanae;Maesa rugosa C.B.Clarke, Maesa

rugosa 1, Bhutan: Grierson & Long 1594 (K), SRR17422080, Indicae;Maesa rugosa C.B.Clarke, Maesa rugosa 2, China: Forrest 16564 (K), SRR17422081,

Indicae;Maesa salicifolia E.Walker, Maesa salicifolia, China: Larsen & Larsen 40765 (AAU), SRR17422079, Indicae;Maesa samoana Mez, Maesa samoana,

Samoa: Bristol 2106 (K), SRR17422078, Papuanae;Maesa sayersii Sleumer, Maesa sayersii 1, Papua New Guinea: Kerenga & Croft LAE77285 (K),

SRR17422075, Papuanae;Maesa sayersii Sleumer, Maesa sayersii 2, Papua New Guinea: Sands & Coode NGF46087 (K), SRR17422077, Papuanae;Maesa

serratifolia Sumanon & Utteridge, Maesa serratifolia, Papua New Guinea: Takeuchi 11855 (K), SRR17422068, Papuanae;Maesa sleumerii Sumanon & Utter-

idge, Maesa sleumerii 1, Indonesia: Raynal 16861 (K), SRR17422072, Papuanae;Maesa sleumerii Sumanon & Utteridge, Maesa sleumerii 2, Indonesia: van

Royen & Sleumer 6313 (K), SRR17422071, Papuanae;Maesa sp. 1,Maesa sp. 1, Solomon Islands: Maenu’u BSIP6097 (K), SRR17422063, Papuanae;Maesa

sp. 2,Maesa sp. 2, Indonesia: de Vogel 5814 (K), SRR17422070, Papuanae;Maesa sp. 3,Maesa sp. 3, Burundi: Reekmans 8194 (K), SRR17422069, Maesa;

Maesa sp. aff. perlaria,Maesa sp. aff. perlaria, Thailand: Newman & al. 1110 (K), SRR17422183, Indicae;Maesa sp. aff. tetrandra,Maesa sp. aff. tetrandra,

Indonesia: Coode 5862 (K), SRR17422182, Papuanae;Maesa sp. johnsii,Maesa sp. johnsii, Indonesia: Johns 9809 (K), SRR17422180, Papuanae;Maesa

sp. mayuii,Maesa sp. mayuii, Papua New Guinea: Stevens & Veldkamp LAE54366 (K), SRR17422181, Papuanae;Maesa spectabilis Sleumer,Maesa spectabilis

1, Indonesia: Utteridge 434 (K), SRR17422179, Papuanae;Maesa spectabilis Sleumer, Maesa spectabilis 2, Indonesia: Utteridge 424 (K), SRR17422178, Pa-

puanae;Maesa cf. striata,Maesa striata/lancifolia, Thailand: Middleton 2912 (K), SRR17422177, Indicae;Maesa sumatrana Scheff., Maesa sumatrana 1, Ma-

laysia: Tagane SWK2628 (FU), SRR17422176, Ramentaceae;Maesa sumatrana Scheff., Maesa sumatrana 2, Malaysia: Tagane SWK2633 (FU),

Version of Record 19

TAXON 00 (00) •1–20 Sumanon & al. •Phylogeny and classification of Maesa

Appendix 1. Continued.

SRR17422175, Ramentaceae;Maesa tabacifolia Mez, Maesa tabacifolia, Samoa: Whistler 11438 (K), SRR17422174, Papuanae;Maesa tagulensis Sumanon

& Utteridge, Maesa tagulensis, Papua New Guinea: Brass 28086 (K), SRR17422067, Papuanae;Maesa tenera Mez, Maesa tenera 1, Japan: Naiki 5578 (K),

SRR17422172, Indicae;Maesa tenera Mez, Maesa tenera 2, Taiwan: Bernardi 19879 (K), SRR17422171, Indicae;Maesa tetrandra (Roxb.) A.DC., Maesa

tetrandra 1, Indonesia: Argent & al. 144 (K), SRR17422168, Papuanae;Maesa tetrandra (Roxb.) A.DC., Maesa tetrandra 2, Palau: Costion 3303 (K),

SRR17422170, Papuanae;Maesa tetrandra (Roxb.) A.DC., Maesa tetrandra 3, Indonesia: Sidiyasa 2821 (K), SRR17422169, Papuanae;Maesa tetrandra

(Roxb.) A.DC., Maesa tetrandra 4, Indonesia: Vink & Schram BW12091 (K), SRR17422167, Papuanae;Maesa tomentella Mez, Maesa tomentella, Vietnam:

Poilane 27201 (AAU), SRR17422166, Ramentaceae;Maesa tongensis Mez, Maesa tongensis 1, Tonga: Whistler 7103 (K), SRR17422163, Papuanae;Maesa

tongensis Mez, Maesa tongensis 2, Fiji: Smith 1160 (K), SRR17422161, Papuanae;Maesa tongensis Mez, Maesa tongensis 3, Tonga: Crosby 228 (K),

SRR17422164, Papuanae;Maesa tongensis Mez, Maesa tongensis 4, Tonga: Harvey s.n. (K), SRR17422165, Papuanae;Maesa vitiensis Seem., Maesa vitien-

sis 1, Fiji: Smith 6490 (K), SRR17422157, Papuanae;Maesa vitiensis Seem., Maesa vitiensis 2, Fiji: Tothill 358 (K), SRR17422159, Papuanae;Maesa vitiensis

Seem., Maesa vitiensis 3, Fiji: Seemann 287 (K), SRR17422160, Papuanae;Maesa warburgii Mez, Maesa warburgii 1, Indonesia: Sands 522 (K),

SRR17422038, Indicae;Maesa warburgii Mez, Maesa warburgii 2, Indonesia: Sands s.n. (K), SRR17422037, Indicae;Maesa welwitschii Gilg, Maesa welwit-

schii 1, Angola: Goyder & Maiato 7709 (K), SRR17422034, Monotaxis;Maesa welwitschii Gilg, Maesa welwitschii 2, Sudan: Sillitoe 342 (K), SRR17422036,

Monotaxis;Maesa welwitschii Gilg, Maesa welwitschii 3, Sudan: Schweinfurth 3690 (K), SRR17422035, Monotaxis;Maesa welwitschii Gilg, Maesa welwit-

schii 4[M. schweinfurthii], Congo: Liben 3934 (K), SRR17422074, Monotaxis;Maesa welwitschii Gilg, Maesa welwitschii 5[M. zenkeri], Cameroon: Enden-

guele 120 (K), SRR17422033, Monotaxis.

20 Version of Record

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