Botanical Journal of the Linnean Society, 2018, 188, 355–376. With 2 figures.
Phylogenetic study of Plectranthus, Coleus and allies
(Lamiaceae): taxonomy, distribution and medicinal use
ALAN PATON1* , MONTFORT MWANYAMBO2,3 and ALASTAIR CULHAM2
Science Directorate, Royal Botanic Gardens Kew, TW9 3AB, UK
School of Biological Sciences, University of Reading, Whiteknights, Reading, RG6 6AS, UK
3
National Herbarium and Botanic Gardens of Malawi, P. O. Box 528 Zomba, Malawi
2
Received 20 April 2018; revised 12 July 2018; accepted for publication 13 August 2018
Lamiaceae subtribe Plectranthinae, a palaeotropical group of just over 450 species with mainly zygomorphic
flowers and stamens that are contiguous at the point of insertion at the base of the lower corolla lip, include the
medicinally and horticulturally important genus Plectranthus. Plectranthus currently includes the formerly recognized Coleus and Solenostemon. A phylogenetic analysis of the group is presented based on rps16, trnL-F and
trnS-G regions of the plastid genome. Plectranthus as currently recognized is paraphyletic; a clade containing
the type of Coleus and including Solenostemon, Pycnostachys and Anisochilus is sister to the rest of the group.
Three endemic and monotypic Madagascan genera, Dauphinea, Madlabium, Perrierastrum and the Madagascan
Capitanopsis belong to a single clade and are recognized under Capitanopsis; the new combinations are made here.
Plectranthus s.s. is sister to a clade comprising Thorncroftia and Tetradenia. Tetradenia, unlike any other members of Plectranthinae, has actinomorphic corollas and is usually dioecious. A group of other species previously
recognized as Plectranthus form a clade separate from Plectranthus s.s. and is recognized as Equilabium gen. nov.
Estimates of clade age suggest that the genera begin to diversify from the mid to late Miocene. Plectranthinae
are found in dry woodlands, montane grasslands and evergreen forest margins. Shifts between habitats occur in
most clades, although significantly fewer than if the changes were random. The distribution of the clades in the
major habitats is examined. Migration in Plectranthinae was from Africa to Madagascar and Asia, and there is
no evidence of migration back to Africa. The phylogenetic pattern of medicinal use in Plectranthinae is weak, and
issues surrounding this are discussed.
ADDITIONAL KEYWORDS: Africa – Anisochilus – Capitanopsis – endemic – Equilabium – habitat shifts –
Madagascar – medicinal uses – Pycnostachys – Solenostemon – Tetradenia – Thorncroftia.
INTRODUCTION
Subtribe Plectranthinae (tribe Ocimeae, Lamiaceae)
are a palaeotropical group of 11 genera and just over
450 species (Harley et al., 2004) and are the largest of
seven subtribes that belong to the pantropical tribe
Ocimeae (Zhong et al., 2010; Pastore et al., 2011).
The largest genus, Plectranthus L’Hér., is a widely
used medicinal and horticultural genus including >
320 species (Lukhoba, Simmonds, Paton, 2006; Rice
et al., 2011). Plectranthus incorporates the currently
synonymized genera Coleus Lour. and Solenostemon
Thonn. (Harley et al. 2004), names that are frequently
still used in medicine and horticulture (e.g. Vanaja &
*Corresponding author. E-mail: a.paton@kew.org
Annadurai, 2013; Shepherd & Maybry, 2016; Cubey,
2017).
Ocimeae and Plectranthinae have both been
shown to be monophyletic based on a molecular
phylogenetics using the trnL intron, trnL-trnF
intergenic spacer and rps16 intron of plastid
DNA (Paton et al., 2004). Paton et al. (2004) found
Plectranthinae to be sister to subtribe Ociminae
including Ocimum L., but the relationships to
the other subtribes were unresolved. Although
Plectranthinae cannot be diagnosed unambiguously
by a single unifying morphological character, all
members apart from Tetradenia Benth. have all
their stamens inserted at the base of the lower
(anterior) lip of the corolla, a character that is not
found elsewhere in Ocimeae (Paton et al., 2004).
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
355
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
1
356
A. PATON ET AL.
of this paper are to provide an updated molecular
phylogenetic analysis of Plectranthinae, to identify
major clades, to examine congruence with existing
generic limits, to use the phylogenetic analysis to
examine geographical and ecological distribution
of the clades and to build upon previous studies to
further explore the distribution of medicinal use of
the group (Lukhoba et al., 2006) to facilitate further
targeted medicinal and economic research.
As a result of the analyses presented here, several
changes to current generic delimitation are proposed
and the nomenclatural changes necessary to recognize
these generic level changes are made. However, the
bulk of name changes affecting the names of species
currently placed in Plectranthus s.l. will be published
elsewhere, providing a conspectus of all names
published in Plectranthus and Coleus.
MATERIAL AND METHODS
SAMPLING
A survey of herbarium collections was undertaken
to guide sampling of geographical and morphological
diversity in Plectranthinae and clades in Plectranthus
recognized by Paton et al. (2004, 2009, 2013) and
Lukhoba et al. (2006). Recent floristic accounts and
the World Checklist of Selected Plant Families were
also consulted (Codd, 1985; Forster, 1992, 1994, 2011;
Hedge et al., 1998; Suddee et al., 2005; Paton et al.,
2009, 2013; Govaerts et al., 2016 and references
therein). All genera of Plectranthinae recognized by
Harley et al. (2004) were included in the analysis
except Madlabium Hedge as DNA extractions from
available herbarium material of this genus failed to
amplify. Two species of Callicarpa L., two species of
Prostanthera Labill. and one species each of Gmelina
L., Vitex L., Congea Roxb. and Tectona L.f. were selected
as outgroups to represent early diverging lineages
in the family. Nine members of tribe Mentheae and
one of Elsholtzieae were used to represent subfamily
Nepetoideae excluding Ocimeae. Two species each of
Ocimum and Orthosiphon Benth. (Ociminae) and one
species each of Hyptis Jacq. (Hyptidinae) and Isodon
(Schrad. ex Benth.) Spach were chosen to represent
the remaining subtribes of Ocimeae. Living plant
material was sourced from the wild and voucher
specimens deposited at RNG (Mwanyambo, 2008).
Herbarium material was sourced from K and RNG
(acronyms following Thiers, 2018). The study sample
includes 123 species including 97 of the 455 species of
Plectranthinae (Table 1), building on the 31 species
used by Paton et al. (2004) and including a greater
range of narrowly endemic and broadly distributed
species, medicinal species and representatives of
groups of Plectranthus as identified in Lukhoba
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
In the monophyletic Plectranthinae, Paton et al.
(2004) and Lukhoba et al. (2006) recognized two
clades: the Coleus clade and the Plectranthus clade.
The Coleus clade was strongly supported, whereas
the Plectranthus clade had < 50% bootstrap support
(Paton et al., 2004). Neither of these clades could
be unambiguously diagnosed by morphological
characters. The Plectranthus clade comprised the
currently recognized genera Tetradenia, Thorncroftia
N.E.Br., Aeollanthus Spreng., Capitanopsis S.Moore.
and Dauphinea Hedge (Harley et al., 2004) and part of
Plectranthus including the type species, P. fruticosus
L’Hér. The Coleus clade comprised the remaining
species of Plectranthus (including P. amboinicus
(Lour.) Spreng., the type of Coleus), the currently
recognized Anisochilus Benth. and Pycnostachys
Hook. and some genera recently placed in synonymy:
Leocus A.Chev., Neohyptis J.K.Morton, Englerastrum
Briq., Isodictyophorus Briq. and Holostylon Robyns &
Lebrun (Paton et al., 2009, 2013). Paton et al. (2004)
recommended a further analysis with increased taxon
sampling of Plectranthinae to clarify the best way of
dividing the subtribe into monophyletic, communicable
groups. Floristic treatments of Plectranthus in eastern
and southern tropical Africa (Paton et al., 2009, 2013)
suggested that Plectranthus spp. in the Coleus clade
have a larger anterior and reduced posterior (upper)
corolla lip and calyces with a pedicel attaching
opposite the posterior lip of the calyx; whereas those
in the Plectranthus clade have ± equal anterior and
posterior corolla lobes and calyces with a centrally
fixed pedicel.
Most species of Plectranthinae are found in Africa,
but the group also has species in tropical Asia and
Australia; a few species are naturalized in the New
World. Plectranthinae occupy a variety of habitats
including evergreen forest margins, seasonally dry
woodlands and montane grassland, some of the
latter being seasonally flooded. Species are generally
restricted to one of these habitat types, and can be
broadly distributed or narrowly endemic (Forster,
1992, 1994, 2011; Codd, 1985; Hedge et al., 1998; Paton
et al., 2009, 2013; Suddee, Paton & Parnell, 2005).
Lukhoba et al. (2006) reviewed the ethnobotanical
uses of the 62 Plectranthus spp. cited as having
medicinal use in the literature. Medicinal use was
mapped to the phylogenetic tree of Paton et al.
(2004). This work suggested that 70% of medicinal
Plectranthus species belonged to the Coleus Clade
and that medicinal usage tended to be concentrated in
particular clades across the phylogeny.
In the study presented, we increase the number of
sampled Plectranthus spp., including medicinal species
not included in the previous analyses, and include
records of medicinal use in genera of Plectranthinae
not considered by Lukhoba et al. (2006). The aims
PLECTRANTHUS, COLEUS AND ALLIES
357
Table 1. Summary of the taxonomic breadth of sampling and the species numbers sampled
Number of
species
Clade (Paton et al.,
2004, 2009, 2013)
Number of
species sampled
Sample as
a percentage
Anisochilus Wall ex. Benth.
Leocus A.Chev.
Pycnostachys Hook.
Plectranthus L’Hér.
Dauphinea Hedge
Capitanopsis S.Moore
Madlabium Hedge
Thorncroftia N.E.Br.
Tetradenia Benth.
Aeollanthus C.Mart. ex Spreng.
Alvesia Welw.
Total ingroup
Other Ocimeae
Mentheae/Elsholtzieae
Early-diverging lineages
Total sample
17
5
36
322
1
3
1
6
19
42
3
455
Coleus
Coleus
Coleus
Coleus/Plectranthus
Plectranthus
Plectranthus
Plectranthus
Plectranthus
Plectranthus
Plectranthus
Plectranthus
2
1
3
78
1
3
0
1
3
3
2
97
8
10
8
123
10
20
8
25
100
100
0
17
16
7
67
21
et al. (2006). A list of accessions used is provided in
Appendix 1.
An additional attempt was made to include all the
species of a group of similar, presumed closely related
species, to allow study of habitat changes at species
level in a set of taxa that are known to occur across a
range of habitat types. Following a preliminary analysis
(Mwanyambo, 2008), a monophyletic group of mainly
African species with non-saccate, sigmoid corolla tubes
in the Plectranthus clade was chosen for this detailed
analysis [representing clade 2 groups 6, B and E of
Lukhoba et al. (2006); Plectranthus species 4–33 in
Paton et al. (2009); species 10–31 in Paton et al. (2013)].
Twenty-five of 38 species in this group were included,
DNA being unobtainable from several species.
DNA EXTRACTION, PCR AND SEQUENCING
Total genomic DNA was extracted from dried leaf material
or from floral material where good quality leaf material
was not available. Most extractions used a 2 × CTAB
method following protocols in use at Biological Sciences,
University of Reading (Mwanyambo, 2008) or the Jodrell
Laboratory, Kew, both based on Doyle & Doyle (1987). DNA
extracted at the Jodrell Laboratory was further purified
through a caesium chloride gradient. Supplementary
extractions were conducted at the Botanical Garden
laboratories, University of Oslo, using a DNeasy Plant
Mini Kit (Qiagen, Manchester, UK) following the
manufacturer’s instructions. The extracted DNA was
assessed for quality by visual inspection of an ethidium
bromide (0.35 µg/ml) stained TAE pH 8.0 agarose gel and
was then stored in water or TE buffer at −20 °C.
Double-stranded DNA was amplified by the
polymerase chain reaction (PCR) on an AB GeneAmp
PCR System 2700 or 9700 thermocycler (Perkin Elmer,
USA), in a 25 µl reaction volume. Final concentrations
of: 1 × NH4 reaction buffer (Bioline, UK), 3 mM MgCl2,
200 μM each dNTP, 0.1–0.2 µM each primer and 4U
TaqPolymerase; 0.1 mg/ml bovine serum albumin
(BSA) or 0.9M betaine (B0300, Sigma-Aldrich, UK)
were added where necessary.
Three plastid DNA markers: rps16 and trnL-F
(Paton et al. 2004) and trnS-G (Shaw et al., 2005) were
amplified as summarized in Table S1. Amplification
and sequencing of other markers was attempted;
including plastid trnSGCU-trnGUUC-trnGUUC, trnCGCAycf6-psbM, ycf6-psbM-trnDGUC, rps4-trnTUGU-trnLUAA,
trnDGUC-trnTGGU, rpoB-trnCGCA, psbM-trnDGUC, trnTUGUtrnL UAA and trnH GUG-psbA and nuclear G3pdh and
ITS. Due to lack of or patchy amplification of products
(Mwanyambo, 2008), these regions were not surveyed
widely or used in this phylogenetic analysis.
To improve amplification of difficult templates,
BSA and betaine were used extensively. To further
purify some difficult templates the following kits were
employed: MF-Millipore membrane filter, VSWP02500
for drop dialysis; SureClean (Bioline, UK) and
Micropure-EZ Enzyme Removers (Millipore, Bedford,
MA, USA). BioTaq worked well for the majority of
samples, but other enzymes used were Restorase DNA
polymerase (Sigma) and Phusion DNA polymerase (New
England Biolabs, Ipswich, MA, USA) for challenging
samples. The details of primers used and thermocycling
conditions are given in Table S1. All PCR products were
purified for subsequent cycle sequencing using a Qiagen
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
Genus (Harley
et al., 2004)
358
A. PATON ET AL.
SEQUENCE ASSEMBLY AND ALIGNMENT
Trace data were assembled, checked for trace quality
and edited in Seqman II (DNAstar Inc.) and the
resulting consensus sequence files were exported to
Megalign (DNA Star Inc., USA) for initial alignment.
FASTA alignments were later exported to BioEdit
7.2.5 (Hall, 2013). Aligned sequence lengths are: rps16,
total length 1102 (1–691, 698–1102 used in analysis);
trnL-F, total length 1009 (all used in analysis), trnS-G,
total length 1088 (1–477, 561–1088 used in analysis)
and sequences are deposited in GenBank/EBI/DDBJ
(Appendix 1). Aligned files were exported in NEXUS
for analysis using MrBayes (v3.2). The beginning
and end of each alignment where < 80% of the DNA
sequences were available were excluded from analysis
using the EXCLUDE command. Further short regions
with microsatellite-like or other characteristics that
prevented unambiguous alignments were also excluded.
PHYLOGENETIC ANALYSIS
Each DNA region was explored using MrModeltest
v.2.3 (Nylander, 2004) and all best fitted the GTR + I + G
model based on the Akaike information criterion
(Akaike, 1974). For combined data analysis, congruence
between plastid DNA markers was previously tested
and reported (Mwanyambo, 2008). Bayesian Inference
analyses were performed in MrBayes v.3.2.6 (Ronquist
et al., 2012). Gaps were treated as missing data. All the
analyses were conducted with two separate runs each
of four chains for 10 million iterations. Burn-in was
established using Tracer v1.6 (Rambaut et al., 2014)
and trees were sampled every 10 000 th generation
based on tests for autocorrelation of treelength using
the excel ‘corr’ function. The first 1 000 000 trees
were discarded on this basis. Combinable component
consensus trees generated in Bayes trees (Pagel,
Meade & Barker, 2004) were used in subsequent
investigations because these show the best supported
clades, including those with low (< 50%) support.
CHARACTER CODING OF NON-MOLECULAR DATA
For phylogenetic character mapping and ancestralstate reconstruction, species of Plectranthinae were
coded for habitat type, geographical distribution and
medicinal use. The habitat of each species was coded
from herbarium sheets, in-depth revisions (Codd,
1985; Forster, 1992, 1994, 2011; Hedge et al., 1998;
Suddee et al., 2005; Paton et al., 2009, 2013) and field
observations, and this was related to one of four broad
categories: evergreen forest margins; seasonally dry
woodland such as African Brachystegia woodland or
Asian dry dipterocarp woodland; montane grassland
that often burns in dry seasons and seasonally flooded
grassland or marsh. A few species are found in rocky
areas, but these also usually occur in one of the main
habitats and were scored under the relevant habitat
type or scored as polymorphic for habitat if found in
more than one. Occurrence in four major geographical
regions (sub-Saharan Africa, Madagascar, Tropical
Asia and Australia) was recorded. The medicinal uses
of Plectranthus reported in Lukhoba et al. (2006) were
also mapped onto the phylogenetic tree, as individual
classes of use following Cook (1995) and combined into
an ‘any medicinal use’ category. Post-2006 literature
was scanned for any more recently recorded uses of
species of Plectranthinae included in the sample, and
these are listed in Appendix 2. Species of Plectranthinae
were coded for distribution by continent, habitat and
medicinal use category (Treebase http://purl.org/phylo/
treebase/phylows/study/TB2:S22332). Continent and
habitat were multistate characters, and medicinal
use categories were binary. The states were optimized
over all trees to give a character state frequency per
node on the consensus tree. A reduced taxon set of
outgroups was used for optimization analyses, rooted
on Orthosiphon and Ocimum.
The pattern of distribution of the characters on the
consensus tree was explored using randomization
tests in Mesquite v3.04 (Maddison & Maddison, 2015)
using the Reshuffle Character option following the
protocol in Bytebier et al. (2011). Each coded character
was subjected to reshuffling 100 000 times to generate
a frequency graph of treelengths. Characters for which
the actual steps on the consensus tree fell outside the
95th percentile of the randomized distribution were
considered significantly different from random, either
by being clustered (> 95 percentile of shortest tree
lengths) or over-dispersed (> 95 percentile of longest
treelengths). Tests were conducted for distribution,
habitat and medicinal use characters.
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
QIAquick PCR Purification Kit (Qiagen, Manchester,
UK) following the manufacturer’s instructions with
slight modifications. PE buffer was added and left to
stand for 5-15 min during the washing step to increase
yield. DNA cycle sequencing was performed on the
cleaned products in 10 µl reaction volumes. Reaction
components were BigDye Terminator v3.1 (4 µl: Thermo
Fisher Scientific Life Sciences, Waltham, MA, USA),
1 µM primers (as used for PCR, 1.6 µl), Nanopure
water (2.4 µl) and DNA template (3 µl). Thermocycling
parameters were 25 iterations of: 10 s at 96 °C; 5 s at
50 °C; 4 min at 60 °C. The products were run on an
ABI Prism 3100 Genetic Analyser [Life Technologies,
Carlsbad, CA, USA (with 50 cm 16 capillary array)].
Due to sequencing difficulties, the outgroups and
three Plectranthus spp. [P. lactiflorus (Vatke) Agnew,
P. ecklonii Benth. and P. amboinicus] were not sequenced
for the trnS-G region.
PLECTRANTHUS, COLEUS AND ALLIES
359
clade comprising the Madagascan endemic genera
Capitanopsis, Dauphinea and Plectranthus bipinnatus
A.J.Paton (previously recognized as the monotypic
Perrierastrum Guillaumin) (1.00)] and Clade IV [a
group of African Plectranthus with one Asian member
P. mollis (Aiton) Spreng. (1.00)]. Clade IV was more
extensively sampled and internal branches were
generally shorter and less well supported than in
other clades. The backbone of the tree supporting the
relationships between clades I and II, clade III and
clade IV was not strongly supported (< 0.50) and the
MrBayes and the dated BEAST analyses differed in the
topological ordering of these clades. In the Coleus clade,
two clades with a PP of 1.00 were recovered (Fig. 1B).
Coleus clade A contains species of Pycnostachys and
Anisochilus in addition to species of the currently
recognized Plectranthus, and Coleus clade B contains
the type species of Coleus, P. amboinicus.
The dating analysis supported the Plectranthinae
+ Ociminae clade as having diversified from c. 24.65
Mya; Plectranthinae diversified from c. 21.6 Mya and
the Plectranthus and Coleus clades diversified from c.
19.2 and 18.0 Mya, respectively. Alvesia & Aeollanthus
and clades I–IV, diversified between 4.2 Mya (clade
III – Capitanopsis) and 10.75 Mya (clade IV) in the
Plectranthus clade, with the Coleus A and B clades
diversifying from c. 16.9 and 14.4 Mya, respectively.
Species level divergence times varied from 0.5 to 8.0
Mya in the more densely sampled clade IV. The mean
dates of the crown nodes of all clades named above and
the 95% highest posterior density (HPD) intervals are
given in Table 2 and Supporting information, Figure S1.
RESULTS
OPTIMIZATION OF GEOGRAPHY, HABITAT AND
TREE TOPOLOGY AND DATING
MEDICINAL USE
DATING
In the Bayesian analysis using MrBayes and BEAST,
Plectranthinae were retrieved as monophyletic with
a posterior probability (PP) of 1.00; in that clade, two
sister groups, the Plectranthus clade and Coleus clade
[as recognized by Paton et al. (2004) and Lukhoba et al.
(2006)] both also had a PP of 1.00 (Fig. 1A, B). The dated
tree produced in the BEAST analysis is topologically the
same as that produced by MrBayes for all nodes with
a posterior probability > 50% (Supporting Information,
Fig. S1). At the base of the Plectranthus clade (Fig. 1A)
Alvesia Welw. formed the first branch with a PP of
1.00 and the remainder of the Plectranthus clade was
also supported as monophyletic (0.82). Five clades
in this group were strongly supported: Aeollanthus
(1.00); clade I [a clade comprising Tetradenia and
Thorncroftia (0.96)], supported as sister (1.00) to clade
II [Plectranthus s.s., a clade of African and Madagascan
species morphologically similar to the type species
of Plectranthus, P. fruticosus (1.00)]; clade III [a
Geography
All migrations occurred from Africa to other
continents. When distribution states were mapped
onto the phylogenetic results, the majority of internal
nodes were optimized as African (Supporting
information, Fig. S2). Character optimization showed
nine continental migrations, significantly fewer
(P < 0.01) moves between continents than that expected
from a randomized distribution (P = 0.99, > 17 – < 21
steps). Four clades are non-African: the Australian
Plectranthus congestus R.Br. – P. parviflorus Willd.
clade that contains all the Australian species, and the
Asian P. glabratus (Benth.) Alston – P. parishii Prain
clade both in Coleus clade A; the Madagascan endemic
clade III, Capitanopsis and Madagascan species
of Tetradenia in clade I (Figs 1, S2). Of the clades
identified in the previous section only Alvesia and
Aeollanthus are restricted to tropical Africa, although
one Aeollanthus spp. is naturalized in Brazil. Isolated
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
Phylogenetic and divergence time analysis for the
combined data set was performed using BEAST v2.4.6
(Bouckaert et al., 2014), following file processing
using BEAUti. A trial analysis visualized in Tracer
v1.6 (Rambaut et al., 2014) showed there was no
requirement to partition the data. Rate constancy
was rejected for all partitions and therefore we used
the relaxed clock model. The GTR+G+I, birth death
model was implemented. All partitions fit the same
optimal model measured by AIC and were combined
before analysis. Two separate BEAST analyses were
conducted and subsequently combined to ensure a
run did not stall at a local optimum. Rooting follows
the MrBayes analysis. There is no fossil evidence
to constrain the dates of clades in Ocimeae. The
sampling of the analysis is heavily skewed towards
Plectranthinae and thus the priors used by Drew
& Sytsma (2012) for dating Mentheae would be
inappropriate. Therefore, the most recent common
ancestor of the Ocimeae/Elsholtziae taken from Drew
& Sytsma (2012) was used as a calibration point.
This node was constrained at a mean of 56 Mya and
SD of 5% with normal distribution. A Yule tree prior
was used given that we were sampling individuals
from a wide range of species. Tree building ran for 40
million generations sampled every 10 000th generation.
Stationarity was established by the four millionth
generation. Clock models were unlinked. Resulting
trees were explored in TreeAnnotator v1.6.1 prior to
visualization in the program FigTree v1.3.1.
360
A. PATON ET AL.
terminal taxa with extra-African distributions not
included in the clades just described are also mostly
found in Africa except P. emirnensis (Baker) Hedge
(clade II) in Madacascar, P. mollis (clade IV) and
P. scutellarioides (L.) R.Br. (Coleus clade B) in Asia
(Supporting information, Fig. S2).
In Plectranthus clade I, Tetradenia is split between Africa
and Madagascar, with no species in common between
the regions. Madagascan Tetradenia spp. may form a
monophyletic group, although the sample of this genus
is small. The other genus in clade I, Thorncroftia, has six
species all restricted to southern Africa. Plectranthus clade
II (Plectranthus s.s.) is found in Africa and Madagascar,
although the Madagascan members of this clade are only
represented in the analysis by one species. Plectranthus
clade IV is mainly African with only one species included in
the analysis, P. mollis, which is found in Asia. One species,
P. flaccidus Gürke, occurs in both Africa and Madagascar,
but there are no endemic Madagascan species of this clade.
Habitats
Coleus clades A and B and clade IV of the Plectranthus
clade all have representatives in seasonally dry
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
Figure 1. A, Compatible component consensus tree produced from MrBayes analysis showing the outgroups, Plectranthus
clade (P) with Alvesia, Aeollanthus and Plectranthus clades I–IV and the position of the Coleus clade (Fig. 1B). Posterior
probabilities are given below the branches: blue > 0.50 support, red < 0.50. B, Compatible component consensus tree produced from MrBayes analysis, Coleus clade comprising Coleus clades A and B. Posterior probabilities are given below the
branches: blue > 0.50 support, red < 0.50.
PLECTRANTHUS, COLEUS AND ALLIES
361
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
Figure 1. Continued
woodland, evergreen forest margins and montane
grassland, although there was a notable grouping of
related species in similar habitats. Thirty-one changes
of habitat were recorded in the Plectranthinae,
which is significantly fewer than random [P < 0.01
(P = 0.99, > 39 – < 51 steps), Supporting information,
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
362
A. PATON ET AL.
DISCUSSION
Table 2. Crown node ages of recognized clades (Mya).
Columns give the mean age and the minimum and
maximum of the 95% HPD calculated in BEAST
min
mean
max
14.4
16.8
13.8
3.7
3.7
6.1
20.7
21.6
19.2
7.3
6.5
9.7
26.6
26.7
23.8
11.4
9.6
13.1
1.0
4.8
3.0
7.5
5.3
10.6
1.8
4.2
7.0
7.5
14.2
13.1
10.7
10.75
18.0
16.9
14.4
14.2
22.5
20.9
18.3
Fig. S3]. Aeollanthus, Tetradenia and Thorncroftia
can also be found in these three habitats when
all species including those not in the analysis, are
considered. Alvesia and the Madagascan clade III
are only found in dry woodland, whereas clade II,
Plectranthus s.s., is found mainly in evergreen forest
margins or forested gorges (Supporting information,
Fig. S3). The flooded grassland habitat is only
recorded in Coleus clade A.
Medicinal use
Several instances of medicinal use not recorded in
Lukhoba et al. (2006) are reported in Appendix 2. Thirty
species represented in the phylogenetic tree have
recorded medicinal uses. This broad category
(Medicinal use) has 24 steps, just significantly
fewer than random (P = 0.05, > 24, < 31, Supporting
information, Fig. S4). None of the individual classes of
medicinal use reported in Lukhoba et al. (2006) was
distributed across the phylogenetic tree in a pattern
significantly different from randomized data. Of the
named clades, Coleus clade B had the most recorded
medicinal use, with 13 of the 22 sampled species being
used. Internal nodes are only optimized for medicinal
use in the following groups: the P. lasianthus (Gürke)
Vollesen – P. lactiflorus clade, the P. scutellarioides –
P. shirensis (Gürke) A.J.Paton clade, the P. alpinus
(Vatke) O.Ryding – P. diversus S.T.Blake clade, all
in Coleus clade B and in clade A, the Pycnostachys
reticulata (E.Mey.) Benth. – Pycnostachys urticifolia
Hook. clade (Figs 1B, S4).
The phylogenetic analysis presented here supports
the monophyly of Plectranthinae, but Plectranthus,
as currently recognized, is paraphyletic. The division
of Plectranthinae into Plectranthus and Coleus clades
as suggested by Paton et al. (2004) and Lukhoba
et al. (2006) is supported, with support values much
increased over these previous analyses.
There are several morphological features that
can be used to diagnose the clades identified in
the results and thus splitting Plectranthus into
smaller monophyletic clades is the preferred option.
Tetradenia, is morphologically distinct from the rest of
Plectranthinae (Harley et al., 2004; Paton et al., 2004;
Phillipson & Steyn, 2008). It has actinomorphic corollas
and anterior and posterior pairs of stamens separated
by a clear gap at the point of insertion to the corolla,
rather than having a strongly zygomorphic corolla and
stamens contiguous at the base of the lower corolla lip
as in all other Plectranthinae. These differences make
morphological diagnoses of an enlarged Plectranthus
comprising the whole of Plectranthinae, including
Tetradenia, impossible.
The genera recognized here are summarized in
Table 3 and Figure 2. Although only plastid markers
have been used, the fact that the strongly supported
clades recognized at generic rank are either existing
genera with morphological apomorphies and have
been previously informally recognized on the basis
of morphology [Plectranthus clade IV (Paton et al.,
2009, 2013)] or have strong morphological similarity
(Plectranthus clade III), suggests that the recognized
groups themselves are robust, although the deeper
relationships between them still needs to be fully
resolved. The differences between the generic
delimitation here and that proposed by Harley et al.
(2004) and Paton et al. (2009, 2013) are that: Coleus
is recognized at generic rank, corresponding to the
Coleus clade with Pycnostachys, Leocus, Solenostemon
and Anisochilus placed in synonymy; Plectranthus
s.s. is restricted to species similar to the type of
Plectranthus, P. fruticosus (Plectranthus clade II); a new
genus, Equilabium, is created here to include species
in clade IV; Capitanopsis as currently circumscribed
is paraphyletic as P. bipinnatus is included in it, and
therefore the Madagascan endemic and monotypic
genera Dauphinea, Madlabium, Perrierastrum (the last
previously considered as Plectranthus by Harley et al.,
2004) are all placed in synonymy of the Madagascan
endemic Capitanopsis, the earliest generic name
(clade III). Although Madlabium is not sampled in our
analysis, its corolla morphology with a truncate corolla
throat with small upper lobes is similar to the other
taxa in the clade. The necessary new combinations in
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
Ociminae
Plectranthinae
Plectranthus clade
Alvesia
Aeollanthus
Plectranthus clade
I. Tetradenia &
Thorncroftia
Tetradenia
Plectranthus clade II.
Plectranthus s.s.
Plectranthus clade III.
Capitanopsis
Plectranthus clade IV
Coleus clade
Coleus clade A
Coleus clade B
PHYLOGENY AND TAXONOMY
PLECTRANTHUS, COLEUS AND ALLIES
363
Table 3. Genera recognized and diagnostic features
Recognized Genus
and important synonyms
Coleus Lour.
Anisochilus, Holostylon,
Isodictyophorus, Leocus,
Pycnostachys, Solenostemon
Alvesia Welw.
Morphological diagnostic characters
Coleus
Calyx funnel shaped. Corolla with upper lip much
shorter than lower; pedicel attachment opposite
upper calyx lip
Tetradenia Benth.
Plectranthus clade:
Alvesia
Plectranthus clade:
Aeollanthus
Plectranthus clade I
Thorncroftia N.E.Br
Plectranthus clade I
Plectranthus L’Hér.
Germanea Lam.
Plectranthus clade II
Plectranthus s.s.
Capitanopsis S.Moore
Dauphinea, Perrierastrum,
Madlabium
Equilabium Mwanyambo,
A.J.Paton & Culham
Plectranthus clade III
Calyx three-lobed- expanded and membranous in
fruit
Calyx basally circumscissile; calyx tube distally
dorso-ventrally flattened
Corolla actinomorphic; corolla tube straight, funnelshaped; anterior and posterior pairs of stamens
separated by a clear gap at point of insertion on
the corolla
Corolla zygomorphic; corolla tube straight or
curved downwards, cylindrical. Lateral lobes of
the corolla deflexed towards the lower lip, rather
than forming a four-lobed upper lip as in all other
genera except Tetradenia.
Calyx funnel-shaped, Corolla with upper and lower
lips equal in length; lateral lobes of the calyx
adjacent to the lower lobes of the calyx
Calyx variously shaped, expanded and membranous
to cylindrical. Corolla throat truncate; lateral and
upper lobes short.
Calyx funnel-shaped. Upper and lower corolla lips
equal in length; corolla tube strongly sigmoid;
lateral lobes of the calyx held midway between
uppermost and lowermost lobes
Aeollanthus Spreng.
Plectranthus clade IV
Capitanopsis and Equilabium are formally made at
the end of this paper.
Coleus has previously been recognized as a
separate genus, and a good account of the taxonomic
histories of Coleus and Plectranthus was provided by
Codd (1975). Most treatments following Codd have
merged Coleus into Plectranthus, although it was
maintained as a genus in the Flora of China by Li
& Hedge (1994). Coleus was diagnosed by having
fused stamens (Bentham, 1832; Li and Hedge,
1994), but this character is homoplasious as shown
by Paton et al. (2004), and the characters listed in
Table 3 and used by Paton et al. (2009, 2013) to
identify the Coleus clade provide a more stable basis
for diagnosis of Coleus as a genus. Solenostemon
was maintained as a separate genus by Codd
(1975), but Solenostemon here represented by
P. scutellarioides, P. shirensis, P.sigmoideus A.J.Paton
and P. schizophyllus Baker is paraphyletic (Fig. 1B).
Recognition of Solenostemon as a genus would also
render Coleus paraphyletic and so it is not recognized
at generic rank. Intermediates between Coleus and
its synonyms previously recognized at generic rank
by Harley et al. (2004) have been reported in the
past: Pycnostachys (Paton et al., 2009, 2013);
Anisochilus (Suddee et al., 2014) and Leocus (Pollard
& Paton, 2009). In addition, none of the sections
of Coleus or subgenera of Plectranthus recognized
by Codd (1975) is monophyletic. Further work is
required to identify morphological characters to
diagnose Coleus clades A and B, or other clades
within these.
The merging of the Madagascan endemic and
monotypic genera of clade III into Capitanopsis has
not been suggested before. Taxonomic over-splitting
of Madagascan clades into several genera has been
reported by Buerki et al. (2013), investigating the
phylogenetic clustering of Madagascan endemic
genera. These authors also identified recent radiations
and extinctions as factors contributing the recognition
of endemic genera. Both these factors might have
contributed to the over-splitting of this clade. The
variation in calyx form from funnel-shaped, expanded
and membranous in Capitanopsis to tubular and
non-membranous in Dauphinea, Madlabium and
Perrierastrum (Hedge et al., 1998) might reflect
recent rapid radiation in the clade. The stem age of
Capitanopsis clade III is 14.3 Mya, but the extant
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
Clade (Fig. 1)
364
A. PATON ET AL.
species diversification occurs much later with the
crown node at 4.2 Mya (Table 2), which might reflect
a long period of stasis, but more probably extinction of
earlier branches.
DATING AND CHARACTER OPTIMIZATION
The clades recognized here in the Plectranthus clade
and suggested for generic recognition diversified in the
late Miocene to Pliocene [10.75 Mya (Equilabium), 3.0
Mya (Tetradenia)]. However, the Coleus clade has an
earlier crown date (18.0 Mya), although morphologically
identifiable subclades have not been recognized in
this clade suggesting greater degree of morphological
continuity of form in the Coleus clade as opposed to the
Plectranthus clade. Given the lack of available fossil
evidence directly relevant to Plectranthinae, the dated
phylogenetic tree should be regarded as preliminary
and different sampling between the clades may result
in different dating results being found.
There are few eco-phylogenetic studies of African
plants, particularly of those occurring in seasonally dry
woodland, wooded grassland or savanna floras (Bakker
et al., 2005; Holstein & Renner, 2011; Linder, 2014),
even though these habitats are widespread. This is in
part due to the difficulties associated with species-level
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
Figure 2. Summary diagram showing genera recognized in Plectranthinae with species numbers and dates of
major clades. Species featured from top to bottom are: Alvesia rosmarinifolia (Photograph: M. Finckh); Aeollanthus
buchnerianus (Photograph: B. Wursten); Tetradenia nervosa, Plectranthus saccatus (Photographs: both RBG Kew),
Capitanopsis angustifolia (Photograph: P. Lowry), Plectranthus petiolaris (Photograph: N. Couch); Plectranthus barbatus
(Photograph: RBG Kew).
280
12
61
46
13
8
35
455
97
21%
36
1
0
2
0
0
0
39
24
62%
152
11
9
43
13
8
35
271
52
19%
Africa endemic
Africa and Madagascar
Madagascar endemic
Tropical Asia endemic
Widespread in Asia or Asia and Africa
Temperate Asia endemic
Australia
Total
Sample
% sampled
3
0
0
0
0
0
0
3
2
67%
42
0
0
0
0
0
0
42
3
7%
20
0
9
0
0
0
0
29
4
14%
27
0
37
1
0
0
0
65
7
11%
0
0
6
0
0
0
0
6
5
83%
Total
number of
species
Plectranthus
clade III
Capitanopsis
Plectranthus clade
II Plectranthus
s.s.
Plectranthus
clade I
Tetradenia and
Thorncroftia
Aeollanthus
Alvesia
Coleus
clade
Distribution
Shifts in habitat are significantly fewer than if habitat
was randomly distributed on the phylogenetic tree.
The seasonally flooded habitat is only found in Coleus
clade A in the analysis (Supporting Information,
Fig. S3), although a few unsampled Aeollanthus spp.,
including A. engleri Briq., P. orbicularis Gürke and
P. pulcherissimus A.J.Paton of clade IV also occur in this
habitat. With the exception of these few species, habitat
shifts have been between seasonally dry woodland,
evergreen forest margins and montane grassland. In
the Coleus clade and Plectranthus clade IV there are
still several shifts in habitats, predominantly from
dry woodland to either montane grassland or forest.
Similar habitat shifts were reported in Coccinia Wight
& Arn. (Cucurbitaceae), moving between woodland,
forests and arid habitats. (Holstein & Renner, 2011).
As in Coccinia, the diversification of Plectranthinae
clades date from the mid to late Miocene as the
climate became cooler and drier habitats expanded
and rainforests shrunk in range in Africa (Holstein &
Renner, 2011; Hoetzel et al., 2013; Pokorny et al., 2015).
The habitats occupied by Plectranthinae are
contiguous. Dry woodlands are frequently found at midelevations, and mosaics of evergeen forest patches and
Table 4. Total number of species found in each major clade from each of the geographical areas
HABITATS
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
365
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
sampling. An attempt was made to achieve this level
of sampling in Plectranthus clade IV (Equilabium), but
the lack of well-preserved herbarium material and the
difficulty of field collection in many different countries
in a short time period made this challenging and only
62% of species were sampled in this clade (Table 4).
For many studies of large, broadly distributed groups,
comprehensive species-level sampling is not possible
and there is a need for better collection of material for
DNA-based research (Gaudeul & Rouhan, 2013). Due to
the lack of species-level sampling, conclusions based on
character optimization are preliminary and need to be
tested with more in-depth sampling. The morphological
features outlined in Table 3 were used to place all species
of Plectranthinae into one of the recognized clades. This
information is used to examine whether patterns of
character distribution observed in the analysis might
be artefacts of incomplete sampling. The distribution
of species between clades and geographical area is
summarized in Table 4 and the character optimization
studies are interpreted in this context.
Table 4 gives the total number of species found in
each major clade from each of the geographical areas,
using morphological characters to place species not
included in the analysis. It has not been possible to
give species numbers for the Coleus clades A and B due
to the difficulties of morphologically diagnosing these
subclades as discussed above.
Plectranthus
clade IV
Equilabium
PLECTRANTHUS, COLEUS AND ALLIES
366
A. PATON ET AL.
in several different genera, including Ocimum,
Orthosiphon, Platostoma and Syncolostemon, less
speciation in the forest habitat in Ocimineae is seen
than in Plectranthinae.
GEOGRAPHICAL DISTRIBUTION
Continental migrations are significantly fewer than
expected from randomized distribution and there
are no migrations into Africa, although some extant
species occur both in Africa and Asia and are discussed
below. Three historical migrations of Plectranthinae
to Asia from Africa are shown: P. mollis (clade IV);
P. scutellarioides (Coleus clade B) and the P. glabratus –
P. parishii clade (Coleus clade A) (Figs 1, S2). The Indian
P. gardneri Twaites in clade II (not sampled) probably
represents another migration to Asia. Only one of these
migrations shows speciation in Asia: the P. glabratus –
P. parishii clade containing Anisochilus in Coleus clade
A. However, Asian speciation in the P. scutellarioides
and P. shirensis clade in Coleus clade B is also likely, due
to there being other species morphologically similar to
P. scutellarioides in Asia and the Indian P. subincisus
Benth. is suggested to be closely related to the Asian
P. mollis in clade IV, representing another possible
Asian speciation (Smitha & Sunojkumar, 2015). All
Australian species, which are morphologically similar,
arose from a single migration event (1.6 Mya) from
Asia, but increased sampling is necessary to confirm
the monophyly of the Australian species.
There are three historical migration events to
Madagascar: clade I (Tetradenia and Thorncroftia); clade II
(Plectranthus s.s.) and clade III (Capitanopsis) (Supporting
Information, Fig. S2). The migration events from Africa to
Madagascar or to Asia in clades I and III occurred in dry
woodland clades, whereas those in clade II were more likely
through forest habitat species. Eleven species currently
occur in both Africa and Madagascar, and represent both
forest and dry woodland species. This pattern of migration
from Africa to Madagascar mainly through dry habitats,
but also with some through wetter forest, is also seen in
Apocynaceae subfamily Asclepiadoideae (Meve & Liede,
2002), although, unlike this group, there are no migrations
from Madagascar to Africa in Plectranthinae.
A few species, all members of Coleus clade B, are
found in Africa, Madagascar and tropical Asia, including
P. barbatus Andr., P. rotundifolius Spreng., P. amboinicus,
P. hadiensis (Forssk.) Sprenger P. montanus Benth. and
P. caninus Roth. These species are all recorded as having
medicinal uses and so the broad distribution might
reflect trade and human transport.
USES
In Plectranthinae, the pattern of distribution of any
particular medicinal use as categorized by Lukhoba
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
montane grassland occur in adjacent higher elevations,
particularly in eastern Africa. With variations in aridity,
the boundaries between these habitats are likely to
move, creating a dynamic landscape (Oliveras & Malhi,
2016; Fer et al., 2017), influencing the spread and
restriction of species distributions. Another parallel
with Coccinia is that some forest species of Plectranthus
clades II and IV and the Coleus clade have wide
discontinuous distributions, perhaps reflecting forest
expansion during the Pleistocene (Holstein & Renner,
2011). Such widespread species include P. kamerunensis
Gürke and P. laxiflorus Benth. in E.H.F.Meyer (clade IV),
P. alboviolaceus Gürke (clade II) and P. alpinus (Coleus
clade). On the other hand, the disjunct distribution of
P. leptophyllus (Baker) A.J.Paton (Coleus clade) found in
the mountains in Uganda, coastal Kenya and Tanzania
and in eastern Zimbabwe and adjacent Mozambique, or
the occurrence of P. sylvestris Gürke and P. melleri Baker
in Africa and Madagascar, probably reflect long-distance
dispersal, as suggested for Coccinia schliebenii Harms
(Holstein & Renner, 2011; Paton et al., 2009, 2013).
Fire might influence the distribution of clades
in Plectranthinae. Clade IV and the Coleus clade
frequently inhabit dry woodland and montane
grassland prone to burning, often having thick
underground fire resistant rootstocks, a character
rare in the other clades. In contrast, Aeollanthus,
Capitanopsis (clade III) and Tetradenia and
Thorncroftia (clade I) are most often associated with
seasonally dry habitats and often have succulent
or thick leaves and sometimes stems. These groups
are mostly absent from evergreen forest margins
and areas of montane grassland that are prone to
burning, unless sheltered by rocks in these habitats.
Clade II (Plectranthus s.s.) also occurs in naturally
fire-free evergreen forest margins or forested gorges
in the summer rainfall area of southern Africa and
in Madagascar. The clade is largely absent from
dry woodland, although c. 10% of species in Africa
and Madagascar have been recorded from that
habitat, but these are often succulent and lack fire
resistant rootstocks. Maurin et al. (2014) suggested
a Pleistocene origin, < 5.3 Mya, for the fire-resistant
geoxylic life form seen in clade IV and the Coleus
clade. This date is consistent with recent species and
habitat diversification across habitats in these clades.
Ociminae, sister to Plectranthinae, have few
evergreen forest margin species and there are about
four times as many species of Plectranthinae as
Ociminae in the forest margin habitat (Hedge et al.,
1998; Suddee et al., 2005; Paton et al., 2009, 2013).
More resolved relationships of Ociminae are needed
to investigate the pattern of migration and speciation
and the relative importance of factors in explaining
this difference between sister groups. However, as
the relatively few forest species of Ocimineae occur
PLECTRANTHUS, COLEUS AND ALLIES
CONCLUSIONS
The major taxonomic conclusions for this medicinally
and horticulturally important group are that Coleus,
including Solenostemon with > 270 species, is sister to
the remainder of Plectranthinae and merits generic
recognition. Plectranthus s.s. (clade II) is a group of
only c. 65 species and is sister to a clade comprising the
morphologically distinct Tetradenia and Thorncroftia.
The species of clade IV need to be moved from Plectranthus
into a separate genus, Equilabium. The Madagascan
clade III can be recognized as Capitanopsis, with three
previously recognized monotypic genera moved into it.
Although changes in habitat are significantly fewer
than would be expected if there were no phylogenetic
pattern, shifts between habitats do occur. The lack of
complete species-level phylogenetic trees, even when
good taxonomic accounts exist, remains a barrier to
understanding the details and frequencies of these
changes. Herbaria represent an important resource for
such studies and new analytical techniques might provide
opportunities for creating such detailed phylogenetic
trees from degraded DNA from herbarium specimens
(Dodsworth, 2015). However, such studies will still rely
on good taxonomic accounts and well-curated herbaria.
Information on the medicinal use of plants remains
fragmented and difficult to synthesize. Papers that
deal with medicinal use tend to be regionally based and
rarely present results on the underlying chemistry of the
plant, whereas papers focusing on the biochemistry and
medicinal use tend to deal with only a few species. Work
such as that presented here and by Saslis-Lagoudakis
et al. (2011b) provides a framework for further
understanding of the relationship between the use of
plants and shared biochemical pathways or properties.
TAXONOMIC NOVELTIES
A conspectus of all species of Coleus, Plectranthus and
Equilabium is being prepared separately, including for
the first time the formal placing of Anisochilus and
Pycnostachys in the synonymy of Coleus. Equilabium
is described and the necessary combinations in
Capitanopsis are made below.
Equilabium Mwanyambo, A.J.Paton & Culham gen. nov.
urn:lsid:ipni.org:names:60475121-2
Type species: Equilabium laxiflorum (Benth.)
Mwanyambo, A.J.Paton & Culham comb. nov.
urn:lsid:ipni.org:names:60475122-2
Basionym: Plectranthus laxiflorus Benth. in
E.H.F.Meyer, Comm. Pl. Afr. Austr.: 228 (1838).
Lectotype, chosen by Codd (1975): South Africa,
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
et al. (2006) is not significantly different from random,
contrasting with previous studies suggesting that
medicinal use is not randomly distributed across
phylogenetic trees (Douwes et al., 2008; Rønsted et al.,
2008; Saslis-Lagoudakis et al., 2011a). However, when
all medicinal uses are regarded together as a single
character, the pattern of distribution is just significant
at the 0.05 level. Several instances of use have been
recorded in Tetradenia riparia (Hochst.) Codd. This
name was previously used to cover several tropical
African species now separated as distinct species
following Phillipson & Steyn (2008). It is possible
that some of the recorded medicinal use attributed
to T. riparia actually applies to T. tanganyikae
Phillipson and, if that species is scored as having
medicinal use, then the pattern of medicinal use is no
longer significantly different from random across the
phylogenetic tree. A non-significant pattern of any
medicinal use has also been reported in Pterocarpus
Jacq. (Fabaceae; Saslis-Lagoudakis et al., 2011b),
although in that study some individual classes of
medicinal use were significantly clustered on the
phylogenetic tree, unlike in Plectranthinae. The
lack of a clear phylogenetic pattern in medicinal use
recorded here might be a consequence of relatively
sparse and inconsistent depth of sampling across
clades and/or the equal scoring of non-homologous
medicinally active compounds that may derive
from different biosynthetic pathways. The lack of a
strong pattern across the whole of Plectranthinae
is consistent with the findings of Kelly, Grenyer &
Scotland (2014), who suggested that phylogenetic
distance is correlated with feature similarity for only
short distances along the tree, and those of Rønsted
et al. (2012), who suggested that the strength of
correlation is dependent on taxonomic scale.
Investigations into potential medicinal use
could be focused on clades in which interior nodes
are optimized as showing this character. Clade B
includes the highest number of medicinal species
recorded in Lukhoba et al. (2006) Several species in
the P. lasianthus–P. lactiflorus clade (clade B, Figs 1,
S4) with medicinal use were placed by Codd (1975)
in Plectranthus subgenus Calceolanthus Codd. The
subgenus was diagnosed by having a calyx with a
dense beard of hairs in the calyx throat, although
the analysis presented here suggests not all species
in this clade share this character, e.g. P. puberulentus
K.Morton and P. lanuginosus (Benth.) Agnew. Despite
this, species sharing this character are likely to be
closely related. Species unstudied for medicinal use
and with dense hairs in the calyx throat include
P. pentheri (Gürke) van Jaarsv. & T.J.Edwards,
P. xylopodus Lukhoba & A.J.Paton, P. ornatus
Codd, P. grandicalyx (E.A.Bruce) J.K.Morton and
P. otostegioides (Gürke) Ryding (Paton, 2009, 2013).
367
368
A. PATON ET AL.
Capitanopsis brevilabra (Hedge) Mwanyambo,
A.J.Paton & Culham comb. nov.
urn:lsid:ipni.org:names:77165451-1
Basionym: Dauphinea brevilabra Hedge, Notes Roy.
Bot. Gard. Edinburgh 41: 119 (1983). Type: Material
cultivated in Edinburgh, originally collected in
Madagascar, Dist. de Fort Dauphin, Ste-Luce, Hardy
& Rauh 2876 (E, holotype).
Capitanopsis magentea (Hedge) Mwanyambo,
A.J.Paton & Culham comb. nov.
urn:lsid:ipni.org:names:77165452-1
Basionym: Madlabium magenteum Hedge, Fl. Madag.
175: 261. 1998. Type: Madagascar, forêt d’Ampandra,
6 km au nord de Vohemar, sur la route vers Ambilobe,
Lavranos 28995 (E, holotype P, isotype).
Capitanopsis oreophila (Guillaumin) Mwanyambo,
A.J.Paton & Culham comb. nov.
urn:lsid:ipni.org:names:77165453-1
Basionym: Perrierastrum oreophilum Guillaumin,
Bull. Mus. Natl. Hist. Nat., sér. 2, 2: 694. 1930. Type:
Madagascar, massif de l’Andringitra, Perrier de la
Bâthie 13729 (P, holotype).
Synonym: Plectranthus bipinnatus A.J.Paton,
Kew Bull. 58: 488. 2003. Type as for Perrierastrum
oreophilum
ACKNOWLEDGEMENTS
Thanks are due to Victor Albert for hosting Montfort
Mwanyambo at the University of Oslo and the
Norwegian Ministry of Foreign Affairs, SADC
Biodiversity Support Programme MWI-04/333 for
funding Montfort Mwanyambo during his PhD studies. We thank Bart Wursten (Aeollanthus), Manfred
Finckh (Alvesia), Peter Lowry (Capitanopsis) and Neil
Crouch (Plectranthus petiolaris) for permission to use
photographs in Figure 2. We thank two anonymous
reviewers for their constructive comments on an earlier version of the manuscript.
REFERENCES
Akaike H. 1974. A new look at the statistical model identification. IEEE Transactions on Automatic Control 19: 716–723.
Anthoney ST, Ngule CM. 2013. Chemical constituents of
infused Plectranthus argentatus leaves. World Journal of
Science 1: 151–160.
Awas T, Demissew S. 2009. Ethnobotanical study of medicinal plants in Kafficho people, southwestern Ethiopia. In:
Ege S, Aspen H, Teferra B, Bekele S, eds. Proceedings of the
16th International Conference of Ethiopian Studies, Vol. 3.
Trondheim: NTNU-Trykk Press, 711–726.
Bakker FT, Culham A, Marais EM, Gibby M. 2005. Nested
radiation in Cape Pelargonium. In: Bakker FT, Chatrou LW,
Gravendeel B, Pelser PB, eds. Plant species-level systematics: new
perspectives on pattern & process. Ruggel: Gantner Verlag, 75–100.
Bascombe K, Gibbons S. 2008. Anti-staphylococcal activity
of novel diterpenes isolated from Pycnostachys reticulata.
Planta Medica 74: 1047.
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
KwaZulu-Natal, between Umzimkulu and Umkomaas
Rivers, Drège 3586 (K!, lectotype).
Equilabium is similar to Coleus and Plectranthus
in having a strongly zygomorphic corolla and a funnelshaped calyx with a broad upper lip and a lower lip with
four lanceolate teeth, and in having stamens contiguous at
the point of insertion at the base of the lower corolla lip.
It differs from Coleus in having equal corolla lips, rather
than the upper lip being shorter than the lower, and in
having a symmetrical attachment of the pedicel to the base
of the calyx, rather than the pedicel attaching to the calyx
asymmetrically, opposite the upper lip of the calyx. It differs
from Plectranthus by having a strongly to shallowly sigmoid
corolla tube that is parallel-sided at the base (slightly
saccate in only one species), as opposed to a straight or
downward-curved corolla tube that is usually gibbous or
saccate at the base, and in having the lateral lobes of the
calyx held midway between the upper lip and lowermost
teeth of the lower lip, rather than having the lateral teeth
much closer to the lowermost teeth than the upper lip.
Perennial or annual, sometimes succulent, subshrubs
or herbs or geoxylic herbs, usually aromatic. Leaves
simple, sometimes succulent, opposite. Inflorescence
thyrsoid, with cymes sessile or pedunculate, bractate,
rarely bracteolate, one- to three- (to seven-) flowered;
bracts caducous or persistent. Pedicel attaching to calyx
symmetrically. Calyx funnel-shaped, straight, twolipped, five-lobed; posterior lobe lanceolate to obovate,
sometimes decurrent, usually broader than other lobes;
lateral lobes lanceolate or deltoid, held between the
posterior and anterior lobes; anterior lobes lanceolate;
throat open, glabrous. Corolla strongly two-lipped, fivelobed, white, blue or purple; posterior lip, ascending
or erect, four-lobed, median lobes exceeding lateral;
anterior lip horizontal, cucullate, enclosing stamens,
sometimes frilled at apex, corolla-tube narrow, sigmoid,
parallel-sided at base, dilating distally. Stamens four,
free at base; anthers ± orbicular. Style apex bifid with
subulate lobes. Disc four-lobed with anterior lobe larger.
Nutlets, ovoid, glabrous, usually mucilaginous.
The new combinations in Capitanopsis are
made below:
PLECTRANTHUS, COLEUS AND ALLIES
Govaerts R, Paton A, Harvey Y, Navarro T, García Peña
MR. 2016. World checklist of Lamiaceae. Facilitated by the
Royal Botanic Gardens, Kew. Published on the Internet;
http://apps.kew.org/wcsp/. Retrieved 15 Jan 2016.
Hall T. 2013. BioEdit. Available at: http://www.mbio.ncsu.edu/
BioEdit/bioedit.html.
Harley RM, Atkins S, Budantsev A, Cantino PD, Conn
B, Grayer RJ, Harley MM, De Kok R, Krestovskaja T,
Morales A, Paton AJ, Ryding O, Upson T. 2004. Labiatae.
In: Kadereit JW, ed. The families and genera of vascular
plants (Lamiales), Vol. 6. Berlin: Springer, 167–275.
Hedge IC, Clement RA, Paton AJ. Phillipson PB. 1998.
Flore de Madagascar et des Comores, Famille 175: Labiatae.
Paris: Muséum National d’Histoire Naturelle.
Hoetzel S, Dupont L, Schefuß E, Rommerskirchen F, Wefer
G. 2013. The role of fire in Miocene to Pliocene C4 grassland
and ecosystem evolution. Nature Geoscience 6: 1027–1030.
Holstein N, Renner SS. 2011. A dated phylogeny and collection records reveal repeated biome shifts in the African genus
Coccinia (Cucurbitaceae). BMC Evolutionary Biology 11: 28.
Juch M, Rüedi P. 1997. Isolation, structure, and biological
activities of long‐chain catechols of Plectranthus sylvestris
(Labiatae). Helvetica Chimica Acta 80: 436–448.
Kelly S, Grenyer R, Scotland RW. 2014. Phylogenetic
trees do not reliably predict feature diversity. Diversity and
Distributions 20: 600–612.
Kaou AM, Mahiou-Leddet V, Hutter S, Aïnouddine
S, Hassani S, Yahaya I, Azas N, Ollivier E. 2008.
Antimalarial activity of crude extracts from nine African
medicinal plants. Journal of Ethnopharmacology 116: 74–83.
Lekphrom R, Kanokmedhakul S, Kanokmedhakul
K. 2010. Bioactive diterpenes from the aerial parts of
Anisochilus harmandii. Planta Medica 76: 726–728.
Li H-W, Hedge IC. 1994. Lamiaceae. In: Wu Z-Y, Raven PH.
eds. Flora of China, Vol. 17. Beijing: Scientific Press and
Missouri Botanical Garden, 50–299.
Linder HP. 2014. The evolution of African plant diversity.
Frontiers in Ecology and Evolution 2: 38.
L u k h o b a C W, S i m m o n d s M S , Pa t o n A J. 2 0 0 6 .
Plectranthus: a review of ethnobotanical uses. Journal of
Ethnopharmacology 103: 1–24.
Maddison WP, Maddison DR. 2015. Mesquite: a modular
system for evolutionary analysis. Version 3.05. Available at:
http://mesquiteproject.org.
Maurin O, Davies TJ, Burrows JE, Daru BH, Yessoufou K,
Muasya AM, van der Bank M, Bond WJ. 2014. Savanna
fire and the origins of the ‘underground forests’ of Africa.
New Phytologist 204: 201–214.
Meve U, Liede S. 2002. Floristic exchange between mainland Africa and Madagascar: case studies in Apocynaceae–
Asclepiadoideae. Journal of Biogeography 29: 865–873.
Moteetee A, Van Wyk BE. 2011. The medical ethnobotany of
Lesotho: a review. Bothalia 41: 209–228.
Mwanyambo ML. 2008. Phylogeny and biogeography of
Plectranthus L’Hérit (Ocimeae: Nepetoideae: Lamiaceae) with
emphasis on taxa occurring on the Nyika Plateau Malawi.
Unpublished PhD thesis, The University of Reading.
Njau EFA, Alcorn JM, Buza J, Chirino-Trejo M,
Ndakidemi P. 2014. Antimicrobial activity of Tetradenia
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
Bentham G. 1832. Coleus in Labiatarum genera et species.
London: J. Ridgway and Sons, 47–59.
Bouckaert R, Heled J, Kühnert D, Vaughan T, Wu C-H,
Xie D, Suchard MA, Rambaut A, Drummond AJ. 2014.
BEAST 2: a software platform for Bayesian evolutionary
analysis. PLoS Computational Biology 10: e1003537.
Buerki S, Devey DS, Callmander MW, Phillipson PB,
Forest F. 2013. Spatio‐temporal history of the endemic genera of Madagascar. Botanical Journal of the Linnean Society
171: 304–329.
Bytebier B, Antonelli A, Bellstedt DU, Linder HP. 2011.
Estimating the age of fire in the Cape flora of South Africa
from an orchid phylogeny. Proceedings of the Royal Society B:
Biological Sciences 278: 188–195.
Codd LE. 1975. Plectranthus (Labiatae) and allied genera in
southern Africa. Bothalia 11: 371–442.
Codd LE. 1985. Flora of southern Africa. 28, 4 Lamiaceae.
Pretoria: Botanical Research Institute, Department of
Agriculture and Walter Supply, Republic of South Africa.
Cook FEM. 1995. Economic botany data collection standard.
Kew: Royal Botanic Gardens.
Cubey J. 2017. RHS plant finder 2017. London: Royal
Horticultural Society.
Dodsworth S. 2015. Genome skimming for next-generation
biodiversity analysis. Trends in Plant Science 20: 525–527.
Douwes E, Crouch NR, Edwards TJ, Mulholland DA.
2008. Regression analyses of southern African ethnomedicinal plants: informing the targeted selection of bioprospecting and pharmacological screening subjects. Journal of
Ethnopharmacology 119: 356–364.
Doyle JJ, Doyle JL. 1987. A rapid DNA isolation procedure for small quantities of fresh leaf tissue. Phytochemical
Bulletin, Botanical Society of America 19: 11–15.
Drew BL, Sytsma KJ. 2012. Phylogenetics, biogeography,
and staminal evolution in the tribe Mentheae (Lamiaceae).
American Journal of Botany 99: 933–953.
Fawole OA, Amoo SO, Ndhlala AR, Light ME, Finnie JF,
Van Staden J. 2010. Anti-inflammatory, anticholinesterase, antioxidant and phytochemical properties of medicinal plants used for pain-related ailments in South Africa.
Journal of Ethnopharmacology 127: 235–241.
Fer I, Tietjen B, Jeltsch F, Trauth MH. 2017. Modelling
vegetation change during Late Cenozoic uplift of the East
African plateaus. Palaeogeography, Palaeoclimatology,
Palaeoecology 467:120–130.
Forster PI. 1992. Five new species of Plectranthus L. Hérit
(Lamiaceae) from Queensland. Austrobaileya 3: 729–740.
Forster PI. 1994. Ten new species of Plectranthus L’Her.
(Lamiaceae) from Queensland. Austrobaileya 4: 159–186.
Forster PI. 2011. Five new species of Plectranthus L. Hér.
(Lamiaceae) from New South Wales and Queensland.
Austrobaileya 8: 387–404.
Fowler DG. 2006. Traditional fever remedies: a list of Zambian
plants. Available at: http://citeseerx.ist.psu.edu/viewdoc/dow
nload?doi=10.1.1.527.9450&rep=rep1&type=pdf. Accessed
16 Dec. 2016.
Gaudeul M, Rouhan G. 2013. A plea for modern botanical
collections to include DNA-friendly material. Trends in Plant
Science 18: 184–185.
369
370
A. PATON ET AL.
Rønsted N, Symonds MR, Birkholm T, Christensen SB,
Meerow AW, Molander M, Mølgaard P, Petersen G,
Rasmussen N, Van Staden J, Stafford GI. 2012. Can
phylogeny predict chemical diversity and potential medicinal activity of plants? A case study of Amaryllidaceae. BMC
Evolutionary Biology 12: 182.
Saslis-Lagoudakis CH, Williamson EM, Savolainen V,
Hawkins JA. 2011a. Cross-cultural comparison of three
medicinal floras and implications for bioprospecting strategies. Journal of Ethnopharmacology 13: 476–487.
Saslis-Lagoudakis CH, Klitgaard BB, Forest F, Francis L,
Savolainen V, Williamson EM, Hawkins JA. 2011b. The
use of phylogeny to interpret cross-cultural patterns in plant
use and guide medicinal plant discovery: an example from
Pterocarpus (Leguminosae). PLoS One 6: e22275.
Shaw J, Lickey EB, Beck JT, Farmer SB, Liu W, Miller J,
Siripun KC, Winder CT, Schilling EE, Small RL. 2005.
The tortoise and the hare II: relative utility of 21 noncoding chloroplast DNA sequences for phylogenetic analysis.
American Journal of Botany 92: 142–166.
Shepherd C, Maybry J. 2016. Solenostemon plant named
‘Monkey Island’. U.S. Patent PP27,179.
Smitha K, Sunojkumar P. 2015. Notes on the identity and
distribution of Plectranthus subincisus (Lamiaceae)—a
poorly known species recollected after 150 years in southern
India. Phytotaxa: 192: 105–111.
Stafford GI, Pedersen ME, van Staden J, Jäger AK.
2008. Review on plants with CNS-effects used in traditional
South African medicine against mental diseases. Journal of
Ethnopharmacology: 119: 513–537.
Suddee S, Paton AJ, Parnell JAN. 2005. A taxonomic revision of tribe Ocimeae Dumort.(Lamiaceae) in continental
South East Asia II. Plectranthinae. Kew Bulletin 60: 3–75.
Suddee S, Nanthawan Suphuntee N, Sommanussa
Saengrit S. 2014. Plectranthus phulangkaensis (Lamiaceae) a
new species from Thailand. Thai Forest Bulletin (Bot.) 42: 6–9.
Taberlet P, Gielly L, Pautou G, Bouvet J. 1991. Universal
primers for amplification of three non-coding regions of chloroplast DNA. Plant Molecular Biology 17:1105–9.
Thiers B. 2018. Index herbariorum: a global directory of public
herbaria and associated staff. New York Botanical Garden’s
Virtual Herbarium. Available at: http://sweetgum.nybg.org/ih/
Vanaja M, Annadurai G. 2013. Coleus aromaticus leaf
extract mediated synthesis of silver nanoparticles and its
bactericidal activity. Applied Nanoscience 3: 217–223.
Waruruai J, Sipana B, Koch M, Barrows LR, Matainaho
TK, Rai PP. 2011. An ethnobotanical survey of medicinal
plants used in the Siwai and Buin districts of the Autonomous
Region of Bougainville. Journal of Ethnopharmacology 138:
564–577.
Zhong JS, Li J, Li L, Conran JG, Li HW. 2010. Phylogeny
of Isodon (Schrad. ex Benth.) Spach (Lamiaceae) and
related genera inferred from nuclear ribosomal ITS, trnLtrnF region, and rps16 intron sequences and morphology.
Systematic Botany 35: 207–219.
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
riparia (Hochst.) Lamiaceae, a medicinal plant from
Tanzania. European Journal of Medicinal Plants 4: 1462.
Nylander JAA. 2004. MrModeltest v2. Program distributed by
the author. Uppsala: Evolutionary Biology Centre, Uppsala
University.
Oliveras I, Malhi Y. 2016. Many shades of green: the dynamic
tropical forest–savannah transition zones. Philosophical
Transactions of the Royal Society B 371: 20150308.
Pagel M, Meade A, Barker D. 2004. Bayesian estimation
of ancestral character states on phylogenies. Systematic
Biology 53: 673–684.
Paton AJ, Springate D, Suddee S, Otieno D, Grayer
RJ, Harley MM, Willis F, Simmonds MS, Powell MP,
Savolainen V. 2004. Phylogeny and evolution of basils
and allies (Ocimeae, Labiatae) based on three plastid
DNA regions. Molecular Phylogenetics and Evolution 31:
277–299.
Paton AJ, Bramley G, Ryding O, Polhill RM, Harvey YB,
Iwarsson M, Willis F, Phillipson PB, Balkwill K, Lukhoba
CW, Oteino D, Harley RM. 2009. Lamiaceae (Labiatae). In:
Beentje HJ, Ghazanfar SA, Polhill RM, eds. Flora of Tropical
East Africa. Lamiaceae (Labiatae): 1–413. Kew: Royal Botanic
Gardens.
Paton AJ, Bramley G, Ryding O, Polhill RM, Harvey YB,
Iwarsson M, Willis F, Phillipson PB, Balkwill K, Oteino
D, Harley RM. 2013. Lamiaceae. In: Timberlake J, ed. Flora
Zambesiaca, 8,8: 1–331. Kew: Royal Botanic Gardens.
Pastore JFB, Harley RM, Forest F, Paton A. van den Berg
C. 2011. Phylogeny of the subtribe Hyptidinae (Lamiaceae
tribe Ocimeae) as inferred from nuclear and plastid DNA.
Taxon 60: 1317–1329.
Pokorny L, Riina R, Mairal M, Meseguer AS, Culshaw V,
Cendoya J, Serrano M, Carbajal R, Ortiz S, Heuertz M,
Sanmartín I. 2015. Living on the edge: timing of Rand flora
disjunctions congruent with ongoing aridification in Africa.
Frontiers in Genetics 6: 154.
Pollard BJ, Paton A. 2009. The African Plectranthus
(Lamiaceae) expansion continues. Vale Leocus! Kew Bulletin
64: 259–261.
Phillipson PB, Steyn CF. 2008. Tetradenia (Lamiaceae) in
Africa: new species and new combinations. Adansonia 30:
177–196.
Rambaut A, Suchard MA, Xie D, Drummond AJ. 2014.
Tracer v1.6. Available at: http://beast.bio.ed.ac.uk/Tracer
Rice LJ, Brits GJ, Potgieter CJ, Van Staden J. 2011.
Plectranthus: a plant for the future? South African Journal
of Botany 77: 947–959.
Ronquist F, Teslenko M, Van Der Mark P, Ayres DL,
Darling A, Höhna S, Larget B, Liang L, Suchard MA,
Huelsenbeck JP. 2012. MrBayes 3.2: efficient Bayesian
phylogenetic inference and model choice across a large model
space. Systematic Biology 61: 539–542.
Rønsted N, Savolainen V, Mølgaard P, Jäger AK. 2008.
Phylogenetic selection of Narcissus species for drug discovery. Biochemical Systematics and Ecology 36: 417–422.
Appendix 1. Species, voucher specimens and GenBank numbers of materials used in analysis. Sequences marked are being deposited in GenBank
Country
Collector and Number
Herbarium
trnL-trnF intron + 3′
exon + spacer
rps16 intron
trnS-trnG
spacer
Aeollanthus buchnerianus Briq.
Malawi
K
AJ505434
AJ505327
MH612699
Aeollanthus densiflorus Ryding
Kenya
K
AJ505435
AJ505328
MH612700
Aeollanthus rhemanii Gürke
Alvesia clerodendroides
(T.C.E.Fr.) Mathew
Alvesia rosmarinifolia Welw.
Anisochilus harmandii Doan
Anisochilus pallidus Benth.
Callicarpa americana L.
Callicarpa japonica Thunb.
Capitanopsis albida (Baker) Hedge
Capitanopsis angustifolia
(Moldenke) Capuron
Capitanopsis cloiselii S.Moore
Clinopodium myrianthum
(Baker) Ryding
Clinopodium vulgare L. subsp.
arundanum (Boiss.) Nyman
Congea tomentosa Roxb.
Dauphinea brevilabra Hedge
Malawi
Tanzania
Brummitt 10401 (cultivated Kew
1970–2734)
Mathew 6137 (cultivated Kew
1970–3760)
M.L.Mwanyambo et al. 746
Sally Bidgood et al. 4547
MAL
K
MH612625
MH612626
MH630063
MH630096
MH612701
MH612741
Zambia
Thailand
Thailand
Cultivated
Cultivated
Madagascar
Madagascar
Harder et al. 3634
S. Suddee et al. 775
S. Suddee et al. 1080
Cult., Kew 081-84-00507
Cult., Kew 1934–12904
P. Lowry 6255
Clement et al. 2117
K
BKF,K,TCD
BKF,K,TCD
K
K
P, MO. Silica K
K
AJ505436
AJ505437
AJ505438
AJ505535
AJ505536
MH612627
AJ505440
AJ505329
AJ505330
AJ505331
AJ505412
AJ505413
MH630093
AJ505333
MH612742
MH612743
MH612744
X
X
MH612736
MH612737
Madagascar
Malawi
R.Capuron 20.490-SF
M.L.Mwanyambo et al. 771
K
MAL
MH612628
MH612629
MH630094
MH630062
MH612738
MH612698
Cultivated
Cult., Kew 453-79-04649
K
AJ505547
AJ505426
X
Cultivated
Madagascar
BHO
K
AJ505530
AJ505441
AJ505411
AJ505334
X
MH612739
Elsholtzia stauntonii Benth.
Gmelina philippensis Cham.
(G. hystrix Schult. ex Kurz)
Hyptis capitata Jacq.
Isodon lophanthoides (Buch.-Ham. ex
D.Don) Kudô
Lavandula maroccana Murb.
Lavandula minutolii Bolle
Melissa officinalis L.
Mentha suaveolens Ledeb.
Nepeta racemosa Lam.
Ocimum filamentosum Forssk.
Cultivated
Cultivated
Wagstaff, s.n.
Hardy & Rauh 2876 (cultivated
Kew 1998–2417)
Wagstaff 356
Cult., Kew 381-74-02999
BHO
K
AJ505526
AJ505527
AJ505406
AJ505407
X
X
Wongprasert et al. s.n.
H.J.M.
Bowen 3993
Upson s.n.
Upson s.n.
Wagstaff 88-09
Cult., Kew 1970–3169
Z.Jamzad s.n.
Brummitt 18993
BKF,K,TCD
RNG
AJ505449
MH612630
AJ505337
MH630131
MH612795
MH612796
RNG
RNG
BHO
K
TARI
K
AJ505461
AJ505462
AJ505529
AJ505541
AJ505432
AJ505466
AJ505347
AJ505348
AJ505410
AJ505418
AJ505325
AJ505352
X
X
X
X
X
MH612793
Thailand
Malaysia
Cultivated
Cultivated
Cultivated
Cultivated
Iran
Kenya
371
Taxon
PLECTRANTHUS, COLEUS AND ALLIES
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
APPENDICES
372
Appendix 1. Continued
Country
Collector and Number
Herbarium
trnL-trnF intron + 3′
exon + spacer
rps16 intron
trnS-trnG
spacer
Ocimum tenuiflorum L.
Origanum vulgare L.
Thailand
Cultivated
K
K
AJ505473
AJ505543
AJ505358
AJ505422
X
X
Orthosiphon rubicundus (D.Don)
Benth.
Orthosiphon schimperi Benth.
Plectranthus acaulis Brummitt &
Seyani
Plectranthus adenophorus Gürke
Plectranthus africanus (Scott-Elliot)
A.J.Paton
Thailand
Suddee 893
Chase 13334 (Cult., Kew
000-69-19317)
Suddee 809
K
AJ505477
AJ505360
X
Malawi
Zambia
M.L.Mwanyambo et al. 769
M.L.Mwanyambo et al. 742
MAL
MAL
MH612631
MH612633
MH630130
MH630064
MH612794
MH612702
Tanzania
Democratic
Rebublic
Congo
Kenya
K.&T.Pocs 87063
Masens da Musa Y. 632
K
K
MH612634
MH612635
MH630105
MH630103
MH612763
MH612758
Mrs. S.F. Polhill 327
K
MH612636
MH630067
MH612705
Thailand
Malawi
Kenya
Suddee et al. 868
M.L.Mwanyambo et al. 762
Lukhoba et al. 501
BKF, K, TCD
MAL
K
AJ505498
MH612637
MH612638
AJ505376
MH630088
MH630115
MH612746
MH612727
MH612773
Thailand
Suddee et al. 869
BKF
AJ505499
AJ505377
X
Tanzania
Cultivated
Cultivated
Tanzania
Madagascar
Cultivated
K
RNG
K
K
K
K
MH612639
MH612640
MH612641
MH612642
MH612643
AJ505501
MH630068
MH630117
MH630122
MH630104
MH630095
AJ505379
MH612706
MH612775
MH612782
MH612759
MH612740
MH612780
S. Africa
Tanzania
S.Bidgood et al. 1918
T.T.Aye s.n.
Cult., Kew 1999-14
Sally Bidgood et al. 3413
Cult., Kew 1988–3186
Chase 8514 (Cultivated
K-1970–3559)
Balkwill et al. 10880
Sally Bidgood et al. 3335
J, K
K
AJ505502
MH612644
AJ505380
MH630070
MH612760
MH612708
Zimbabwe
T.Müller 3592
K
MH612645
MH630087
MH612726
Cultivated
Chase 13336 (Cultivated
K-1991–6)
Cult., Kew 1970–3233
P.I.Forster PIF15180
Brummitt 9700 (Cult., 1991–6)
K
AJ505532
AJ505409
MH612730
K
K
K
MH612646
MH612647
AJ505504
MH630098
MH630120
AJ505382
MH612748
MH612778
MH612761
Plectranthus agnewii Lukhoba &
A.J.Paton
Plectranthus albicalyx S.Suddee
Plectranthus alboviolaceus Gürke
Plectranthus alpinus (Vatke)
O.Ryding
Plectranthus amboinicus (Lour.)
Spreng.
Plectranthus annuus A.J.Paton
Plectranthus argentatus Blake
Plectranthus barbatus Andr.
Plectranthus betonicifolius Baker
Plectranthus bipinnatus A.J.Paton
Plectranthus buchananii Baker
Plectranthus calycinus Benth.
Plectranthus candelabriformis
Launert
Plectranthus chimanimaniensis
S.Moore
Plectranthus ciliatus E.Mey
Plectranthus coeruleus (Gürke) Agnew Malawi
Plectranthus congestus R.Br.
Australia
Plectranthus crassus N.E.Br.
Malawi
A. PATON ET AL.
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
Taxon
Country
Collector and Number
Herbarium
trnL-trnF intron + 3′
exon + spacer
rps16 intron
trnS-trnG
spacer
Plectranthus daviesii (E.A.Bruce)
Mathew
Plectranthus dissectus Brenan
Plectranthus diversus S.T.Blake
Plectranthus djalonensis (A.Chev)
A.J.Paton
Plectranthus ecklonii Benth.
Plectranthus elegans Britten
Plectranthus emirnensis
(Baker) Hedge
Plectranthus esculentus N.E.Br.
Malawi
M.L.Mwanyambo et al. 792
MAL
MH612648
MH630099
MH612749
Malawi
Australia
Zambia
J.D.&E.G.Chapman 7195
J.R.Clarkson&V.J.Neldner 10114
G.Pope, A-R Smith & D.Goyder
2120
T.T.Aye s.n.
J.D.Chapman 6065
R.A.Clement et al. 2057
K
K
K
MH612650
MH612651
MH612652
MH630078
MH630118
MH630107
MH612716
MH612776
MH612765
RNG
K
K
X
MH612653
MH612654
MH918091
MH630089
MH630090
X
MH612728
MH612729
MAL
MH612655
MH630109
MH612767
Plectranthus glabratus
(Benth.) Alston
Plectranthus glandulosus Hook.f.
Plectranthus goetzii Gürke
Plectranthus gracilis Suesseng.
Plectranthus gracillimus (T.C.E.Fr.)
Hutch. & Dandy
Plectranthus guerkei Briq.
Plectranthus hadiensis (Forssk.)
Sprenger
Plectranthus hockii De Wild.
Plectranthus ignotus A.J.Paton
Plectranthus lactiflorus
(Vatke) Agnew
Plectranthus lanuginosus (Benth.)
Agnew
Plectranthus lasianthus (Gürke)
Vollesen
Plectranthus laxiflorus Benth.
Plectranthus leptophyllus (Baker)
A.J.Paton
Plectranthus longipes Baker
Plectranthus masukensis Baker
Plectranthus melleri Baker
Plectranthus modestus Baker
India
M.L.Mwanyambo
et al. 707
J.Klackenberg & R.Lundin 176
K
MH612657
MH630097
MH612747
Nigeria
Malawi
Malawi
Tanzania
J.D.Chapman 4015
M.L.Mwanyambo et al. 765
E.Phillips 3636
S.Bidgood & K.Vollesen 3229
K
MAL
K
K
MH612658
MH612659
MH612660
MH612661
MH630084
MH630076
MH630075
MH630108
MH612722
MH612714
MH612713
MH612766
Tanzania
Ethiopia
L.Festo 723
M.G.Gilbert et al. 9265
K
K
MH612662
MH612663
MH630101
MH630121
MH612752
MH612779
Tanzania
Tanzania
Ethiopia
Goyder et al 3904
S.Bidgood et al. 2544
I.Friis et al. 8874
K
K
K
AJ505443
MH612664
MH612665
AJ505335
MH630110
X
MH612753
MH612768
X
Tanzania
J.M.Grimshaw 9341
K
MH612666
MH630124
MH612785
Botswana
P.A.Smith 2090
K
MH612667
MH630123
MH612784
Ethiopia
Tanzania
M.G.Gilbert et al. 9245
S.Bidgood et al. 4207
K
K
MH612668
MH612669
MH630083
MH630102
MH612721
MH612754
Tanzania
Tanzania
Cameroon
Zambia
O.Hedberg 6825
S.Bidgood et al. 792
R.Letouzey 14998
M.L.Mwanyambo et al. 752
K
K
K
MAL
MH612670
MH612671
X
MH612672
MH630077
MH630071
MH630113
MH630106
MH612715
MH612709
MH612771
MH612764
Cultivated
Malawi
Madagascar
Malawi
373
Taxon
PLECTRANTHUS, COLEUS AND ALLIES
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
Appendix 1. Continued
374
Appendix 1. Continued
Country
Collector and Number
Herbarium
trnL-trnF intron + 3′
exon + spacer
rps16 intron
trnS-trnG
spacer
Plectranthus mollis (Aiton) Spreng.
Plectranthus montanus Benth.
Plectranthus oertendahlii T.C.E.Fr.
Plectranthus parishii Prain
Plectranthus parviflorus Willd.
Plectranthus parvus Oliv.
India
Cultivated
Cultivated
Thailand
Cultivated
Kenya
K
K
K
BKF, K, TCD
RNG
K
MH612673
AJ505538
AJ505534
AJ505511
MH612674
MH612675
MH630072
AJ505383
MH630091
AJ505390
MH630119
MH630081
MH612710
MH612781
MH612731
MH612745
MH612777
MH612719
Plectranthus pauciflorus Baker
Plectranthus petiolaris E.Mey. ex
Benth.
Plectranthus pinetorum A.J.Paton
Plectranthus puberulentus K.Morton
Plectranthus pubescens Baker
Plectranthus punctatus (L.f.) L’Hér.
subsp. edulis (Vatke) A.J.Paton
Plectranthus rungwensis A.J.Paton
Plectranthus sallyae A.J.Paton
Plectranthus sanguineus Britten
Plectranthus schizophyllus Baker
Plectranthus scutellaroides (L.) R.Br.
Plectranthus shirensis (Gürke) A.J.
Paton
Plectranthus sigmoideus A.J.Paton
Plectranthus stenophyllus Baker
Plectranthus stenosiphon Baker
Plectranthus stolzii Gilli
Plectranthus sylvestris Gürke
Plectranthus tenuicaulis (Hook.f.)
J.K.Morton
Plectranthus termiticola A.J.Paton
Tanzania
S. Africa
J.Klackenberg & R.Lundin 260
Chase 8518 (Cult., 1996-1453)
Chase 3380 (Cult., 1969–5789)
Suddee 1144
T.T.Aye s.n.
M.G.Gilbert & Mesfin Tadessa
6713
Mrs. M. Richards 22953
Univ. of Natal K-1996–2729
K
K
MH918093
AJ505512
MH630085
AJ505391
MH612723
MH612725
Malawi
Kenya
Malawi
Kenya
D.J.Goyder & A.J.Paton 3660
Mathew 6830 (Cult., 1970–3784)
M.L.Mwanyambo et al. 778
Lukhoba et al. 505
K
K
voucher, MAL
K
MH918094
AJ505507
MH612676
MH612677
MH630080
AJ505386
MH630074
MH630116
MH612718
MH612783
MH612712
MH612774
Tanzania
Tanzania
Malawi
Malawi
Trinidad
Tanzania
L.B.Mwasumbi 16222
S.Bidgood et al. 2661
Brummitt s.n. (Cult., 1970–2072)
M.L.Mwanyambo et al. 796
Barnard et al. 193
S.Bidgood et al. 4725
K
K
K
MAL
RNG
K
MH612678
MH612679
AJ505513
MH612680
MH612681
MH612682
MH630086
MH630114
AJ505392
MH630125
MH630127
MH630128
MH612724
MH612772
MH612762
MH612786
MH612788
MH612789
Malawi
Tanzania
Malawi
Tanzania
Malawi
Angola
E.G.Chapman 264
S.Bidgood et al. 1951
R.K.Brummitt et al. 16050
M.Richards 9880
R.K.Brummitt 12332
C.Henriques 323
BM
K
MAL
K
K
K
MH612683
MH612632
MH612684
MH612685
MH612687
MH612688
MH630126
MH630066
MH630079
MH630082
MH630112
MH630129
MH612787
MH612704
MH612717
MH612720
MH612770
MH612790
Zimbambwe
Heany Teachers Training College
H.69
Chase 13332 (Cult.,
563-87-04012)
J.A.Mlangwa 631
R.I.Ludanga 1301
K
MH612689
MH630073
MH612711
K
AJ505533
AJ505405
MH612750
K
K
MH612690
MH612691
MH630100
MH630069
MH612751
MH612707
Plectranthus thyrsoideus (Baker)
B.Matthew
Plectranthus triangularis A.J.Paton
Plectranthus vesicularis A.J.Paton
Tanzania
Tanzania
A. PATON ET AL.
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
Taxon
Taxon
Country
Collector and Number
Herbarium
trnL-trnF intron + 3′
exon + spacer
rps16 intron
trnS-trnG
spacer
Plectranthus viphyensis Brummitt &
Seyani subsp. zebrarum (Brummitt
& Seyani) A.J.Paton
Plectranthus welwitschii (Briq.) Codd
Plectranthus xerophilus Codd
Plectranthus zombensis Baker
Prostanthera petrophila B.J.Conn
Prosthanthera nivea Benth.
Pycnostachys reticulata (E.Mey.)
Benth.
Pycnostachys umbrosa Perkins
Pycnostachys urticifolia Hook.
Rosmarinus officinalis L.
Salvia nilotica Juss. ex Jacq
Tectona grandis L.f.
Tetradenia fruticosa Benth.
Tetradenia nervosa Codd
Tetradenia tanganyikae Phillipson
Malawi
M.L.Mwanyambo &
E.S.Kathumba 797
MAL
MH612692
MH630065
MH612703
Cultivated
S.Africa
Malawi
Cultivated
Cultivated
S. Africa
Cult., 1999-15;
Cult., 1989-1322; Hardy 3966
J.L. Balaka & K. Kaunda 378
Chase 6980
Chase 6975
Cult., Kew 1999–2425
K
K
K
K
K
AJ505505
AJ505515
MH612693
AJ505525
AJ505524
AJ505516
AJ505384
AJ505394
MH630111
AJ505404
AJ505403
AJ505395
MH612791
MH612792
MH612769
X
X
MH612755
Kenya
S. Africa
Cultivated
Malawi
Cultivated
Madagascar
Madagascar
Malawi
K
K
K
MAL
BHO
K
K
MAL
AJ505517
AJ505518
AJ505546
MH612695
AJ505528
AJ505519
AJ505520
MH612696
AJ505396
AJ505397
AJ505425
MH918092
AJ505408
AJ505398
AJ505399
MH630092
MH612757
MH612756
X
MH612697
X
MH612732
MH612733
MH612734
S. Africa
Cultivated
Mathew 6067 (Cult., 1970–3755)
Cult., Kew 1999–2426
Cult., Kew 1973 14217
M.L.Mwanyambo et al. 728
Waimea 73P172
Hardy 2910A (Cult., 1989-1324)
Hardy 2910B (Cult., 1993–3116)
M.L.Mwanyambo & E.S.
Kathumba s.n.
L.McDade LM1281
Chase 13331 (Cult., 1975-1177)
J
K
AJ505521
AJ505544
AJ505401
AJ505423
MH612735
X
Cultivated
Chase 8757 (TCMK 15)
K
AJ505539
AJ505416
X
Thorncroftia longifolia N.E.Br.
Thymus serpyllum L. var. citriodorum
(Pers.) Becker
Vitex trifolia L.
PLECTRANTHUS, COLEUS AND ALLIES
375
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
Appendix 1. Continued
376
A. PATON ET AL.
Appendix 2. Medicinal use of sampled species not recorded in previous review of the medicinal uses of Plectranthus
(Lukhoba et al., 2006)
Use
Category (Cook, 2005)
Reference
Aeollanthus buchnerianus
Aeollanthus densiflorus
Anisochilus harmandii
infection/fever
skin
infection/fever
Moteetee & Van Wyk (2011).
Awas & Demissew (2009).
Lekphrom, Kanokmedhakul,
Kanokmedhakul (2010).
Plectranthus argentatus
cure for colds in children
eye and skin diseases
tonic – antimalarial and
antimycobacterial
properties
stomach pain, inflammation
Anthoney & Ngule (2013)
Plectranthus scutellarioides
Plectranthus scutellarioides
headache, coughs
malaria, diarrhoea
Plectranthus shirensis
Plectranthus sylvestris
Pycnostachys reticulata
Pycnostachys urticifolia
Pycnostachys urticifolia
Tetradenia riparia
traditional fever remedy
anti-inflamatory
pain-related ailments
mental diseases
antibacterial
antimicrobial
gastro-urinary,
infection fever, skin
respiratory, pain
infection/fever,
gastro-urinary,
infection/fever
infection/fever
pain
other mental
infection/fever
infection/fever
Waruruai et al. (2011)
Kaou et al. (2008)
Fowler (2006)
Juch & Rüedi (1997).
Fawole et al. (2010)
Stafford et al. (2008)
Bascombe & Gibbons (2008)
Njau et al. (2014)
SUPPORTING INFORMATION
Additional Supporting Information may be found in the online version of this article at the publisher's web-site:
Table S1. Amplification of plastid DNA markers: primers used and thermocycling conditions.
Figure S1. Dated analyses produced by BEAST. Bars indicate 95% highest posterior density interval (HPD).
Numbers give mean ages for crown nodes of named clades. P – Plectranthus clade comprising Alvesia, Aeollanthus
and Plectranthus clades I–IV and C – Coleus clade comprising Coleus clades A and B.
Figure S2. Consensus tree with geographical distribution optimized: sub-Saharan Africa (blue); Madagascar
(green); Asia (yellow) and Australia (black). Grey indicates proportion of trees in which optimization is unresolved. Red indicates proportion in which node is absent. P – Plectranthus clade comprising Alvesia, Aeollanthus
and Plectranthus clades I–IV and C – Coleus clade comprising Coleus clades A and B.
Figure S3. Consensus tree with habitat optimized: dry woodland (green); evergreen forest margins (blue); montane grassland (black); seasonally flooded grassland (white). Grey indicates proportion of trees in which optimization is unresolved. Red indicates proportion in which node is absent. P – Plectranthus clade comprising Alvesia,
Aeollanthus and Plectranthus clades I–IV and C – Coleus clade comprising Coleus clades A and B.
Figure S4. Consensus tree with medicinal use optimized: medicinal use recorded (black); medicinal use not
recorded (white). Grey indicates proportion of trees in which optimization is unresolved. Red indicates proportion
in which node is absent. P – Plectranthus clade comprising Alvesia, Aeollanthus and Plectranthus clades I–IV and
C – Coleus clade comprising Coleus clades A and B.
© 2018 The Linnean Society of London, Botanical Journal of the Linnean Society, 2018, 188, 355–376
Downloaded from https://academic.oup.com/botlinnean/article/188/4/355/5139384 by guest on 16 December 2021
Species