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Phytotaxa 505 (1): 071–084
https://www.mapress.com/j/pt/
Copyright © 2021 Magnolia Press Article PHYTOTAXA
ISSN 1179-3155 (print edition)
ISSN 1179-3163 (online edition)
Accepted by Adam Karremans: 14 Apr. 2021; published: 28 May 2021
https://doi.org/10.11646/phytotaxa.505.1.5
71
An expanded concept of Madisonia including miscellaneous species of
Pleurothallidinae (Orchidaceae): evidence from molecular analysis
ERIC DE CAMARGO SMIDT1,6*, A. L. V. TOSCANO DE BRITO2,3,7, ANNA VICTORIA SILVÉRIO R. MAUAD1,8
& NICOLÁS GUTIÉRREZ MORALES4,5,9
1Universidade Federal do Paraná, Setor de Ciências Biológicas, Departamento de Botânica, Laboratório de Sistemática e Ecologia
Molecular de Plantas, Centro Politécnico, Caixa Postal 19031, Curitiba, PR, 81531–970, Brazil
2Marie Selby Botanical Gardens, 811 South Palm Avenue, Sarasota, FL 34236-7726, U.S.A.
3Orchid Herbarium of Oakes Ames, Harvard University Herbaria, 22 Divinity Avenue, Cambridge, Massachusetts 20138, USA.
4Programa de Pós-Graduação em Ciências Biológicas (Biologia Vegetal), Instituto de Biociências de- Rio Claro, Departamento de
Botânica, Universidade Estadual Paulista - UNESP, Av. 24 A 1515, Bela Vista, 13506-900, Caixa Postal 199, Rio Claro, São Paulo,
Brazil.
5Grupo de Investigación Schultes, Fundación Ecotonos, Cali, Colombia.
6
�
ecsmidt@yahoo.com.br; https://orcid.org/0000-0002-1177-1682
7
�
a.l.v.toscanodebrito@gmail.com; https://orcid.org/0000-0003-4566-3871
8
�
annavmauad@gmail.com; https://orcid.org/0000-0002-4821-9138
9
�
nicolaiequal@gmail.com; https://orcid.org/0000-0002-6592-9326
*Corresponding author: ecsmidt@yahoo.com.br
A.L.V.T.B., E.C.S., and N.G.M. designed the study and collected samples; A.V.S.R.M. and N.G.M. performed the laboratory
work; E.C.S. did the phylogenetic analyses; A.L.V.T.B., A.V.S.R.M., E.C.S. and N.G.M. wrote the manuscript.
Abstract
Prior taxonomic studies in subtribe Pleurothallidinae have suggested a close relationship between miscellaneous species
featuring long-repent, segmented rhizomes, abbreviated ramicauls, few-flowered inflorescences, and flowers with partially
connate sepals and trilobed lip. The lack of phylogenetic information for most species has prevented further conclusions or
changes in their taxonomy; and as a result, they are currently assigned to several unrelated genera: Anathallis, Madisonia,
Pabstiella, Pleurothallis, Sansonia and Specklinia. We performed phylogenetic analyses using nuclear (nrITS) and five
plastid (matK, psbD-trnT, rps16-trnQ, trnH-psbA and trnS-trnG) markers and demonstrated that these species form an
isolated clade which requires generic recognition. The name Madisonia, previously a monotypic genus endemic of the
Amazon basin, is re-circumscribed and expanded to include nine species distributed in the Atlantic Rainforest and the
Caribbean. Eight new nomenclatural combinations are proposed.
Keywords: Anathallis; Neotropics; Pabstiella; Sansonia; Specklinia; Systematics
Introduction
Genus Madisonia Luer (2004: 258) was described on the basis of Pleurothallis kerrii Braga (1981: 172), a species
endemic to the Amazon basin (Luer 2006, BFG 2015, 2018). It has been considered a monotypic genus (Luer 2004,
2006, Karremans 2016) recognized by the long-repent, segmented rhizome, and short ramicauls, both covered by
ciliate sheaths; sessile, elliptical to subcircular leaves; successively few-flowered raceme, which arises from the apex
of the ramicaul with a long peduncle; small flowers whose lateral sepals are connate at the base to form a mentum, and
a trilobed lip (Luer 2006).
The phylogenetic placement of Madisonia kerrii (Braga) Luer (2004: 258) among the Pleurothallidinae is unknown
and no closely related taxa have been suggested in the available literature (Braga, 1981; Luer 2006). Karremans (2016)
placed Madisonia among the taxa with uncertain affinities and referred to Anathallis spiculifera (Lindley 1859: 43)
Luer (2009: 259) and Pabstiella brasilica Luer & Toscano (2012: 310) as possible relatives given that they share
a long-repent habit, abbreviated ramicauls, elongate peduncle, and small flowers with trilobed lip. Both Pabstiella
SMIDT ET AL.
72 • Phytotaxa 505 (1) © 2021 Magnolia Press
brasilica and Specklinia ianthina Pessoa & Barros (2014: 131) were originally compared with Anathallis spiculifera
in their protologues.
Sansonia Chiron (2012: 80) comprises two species endemic to the Atlantic Rainforest, Sansonia bradei (Schlechter
1922: 39) Chiron (2012: 82) and S. vanderbergii Chiron (2012: 85). They are similar in habit to Anathallis spiculifera
and Pabstiella brasilica, but the single-flowered inflorescence has a very short peduncle. The flowers are also
campanulate, with a well-defined synsepal and a trilobed lip (Chiron 2012). Phylogenetically, Sansonia occupies an
early-diverging position in the subtribe (Chiron et al. 2012, Gutiérrez Morales et al. 2020). Karremans (2016) placed
Sansonia in the Octomeria affinity together with Octomeria R.Br in Aiton (1813: 211), Atoploglossum Luer (2004:
255), and Brachionidium Lindley (1859: 8).
In this work, we have aimed to evaluate the phylogenetic position of the species assigned to Madisonia and
Sansonia, as well as several morphologically similar taxa. We discuss the possible implications of the newly accessed
relationships on the systematics of Pleurothallidinae.
Material & methods
Taxon sampling:—We sampled 49 taxa, five are outgroups belonging to subtribes Bletinae and Laeliinae subtribes
sensu Chase et al. (2015). The remaining 44 taxa belong to the Pleurothallidinae, representing 23 genera and six of the
nine affinities sensu Karremans (2016). Voucher information and GenBank accessions for the 49 taxa are provided in
Table 1.
DNA extraction, amplification and sequencing:—For the newly sequenced taxa, DNA was extracted from fresh
leaf material using the CTAB protocol of Doyle & Doyle (1987) without the addition of RNase A and scaled to 2 mL
microtubes. The amplification was performed in 20 µL PCRs using TopTaq Master Mix kit (QIAGEN Biotechnology),
with 0.2 µM of each primer, and 20–50 ng genomic DNA, following the manufacturer’s guidelines. The targeted
regions were the nrITS with the primers 17SE and 26SE (Sun et al. 1994), partial matK gene with the primers 19F
and 881R (Pridgeon et al. 2001), and four intergenic spacers with the primer pairs psbD and trnT(GGU)-R (Shaw
et al. 2007), rps16x1 and trnQ(UUG) (Shaw et al. 2007), trnHf_05 (Tate 2002) and psbA3-f (Sang et al. 1997), and
trnS(GCU) and trnG(UUC) (Shaw et al. 2005). The thermocycler was programmed for an initial pre-melt at 94°C for
1 minute, followed by 40 cycles of denaturation at 94°C for 30 seconds, annealing at 51°C (nrITS)/ 53°C (plastid)
for 40 seconds, extension at 72°C for 40 seconds, and finalized with another extension step at 72°C for 5 min. PCR
products were purified with 10% polyethylene glycol (PEG) and 80% ethanol (Paithankar & Prasad 1991). Sanger
sequencing reactions were performed by Macrogen Inc. (Seoul, South Korea; http://dna.macrogen.com) or WEMSeq
Biotecnologia (Universidade Federal do Paraná, Curitiba, Brazil), using BigDye Terminator version 3.1 kit (Applied
Biosystems, California, USA).
Sequence alignment:—The sequences were assembled and edited with Geneious Prime® 2019.1.1 (https://www.
geneious.com). Multiple sequence alignments were performed using MAFFT 7 (Katoh & Standley 2013) with default
settings in the auto-strategy algorithm (1 PAM, K = 2), and visually inspected and manually adjusted in Geneious
Prime. Indels (insertions/deletions) were treated as missing data.
Phylogenetic analyses:—Phylogenetic analyses were performed using Maximum Likelihood (ML) and Maximum
Parsimony (MP) to explore results under different assumptions. ML phylogenetic trees were calculated using IQ-
TREE 2.1.2 (Minh et al. 2020) in a single run, with 1,000 ultra-fast bootstrap replicates with -bnni strategy to reduce
overestimation risk (Minh et al. 2013, Chernomor et al. 2016). The best-fit substitution model was also estimated
in IQ-TREE using ModelFinder (Kalyaanamoorthy et al. 2017), under Akaike information criterion (AIC, Table
2). MP phylogenetic trees were performed with Fitch (1971) parsimony using PAUP 4.0b10a (Swofford 2002). The
analyses included 1,000 random taxon-addition replicates, holding 10 trees per replicate, and using the tree-bisection
reconnection (TBR) swapping algorithm, followed by a second search to explore all topologies from the previous
one, limited to 10,000 trees. Support was estimated by 1,000 bootstrap replicates (Felsenstein 1985) using simple
addition, the TBR algorithm, and 20 trees held per replicate. Bootstrap percentages were categorized as weak (51–75),
moderate (76–90), and strong support (91–100), while percentages under 50 were disregarded (e.g., Whitten et al.
2007). Individual dataset trees, strict consensus trees and bootstrap consensus trees were visually examined to assess
congruence among datasets. Due to the absence of moderate to strongly supported phylogenetic incongruences, the
matrices of plastid and nuclear markers were combined (Wiens 1998, Whitten et al. 2005). The resulting phylogenetic
trees were edited in FigTree v.1.4.4 (http://tree.bio.ed.ac.uk/) and CorelDRAW© v.18.0.0.448 (http://www.coreldraw.
AN EXPANDED CONCEPT OF MADISONIA Phytotaxa 505 (1) © 2021 Magnolia Press • 73
com). The aligned data matrix with 6,725 characters (769 from nrITS and 5,956 from cpDNA) is available in TreeBASE
(http://purl.org/phylo/treebase/phylows/study/TB2: 27227).
TABLE 1. Taxa included in this study, vouchers and GenBank (NCBI) accession numbers. Bold accession numbers refer to
new sequences generated for this study.
Taxon Voucher nrITS matK psbD-trnT rps16-trnQ trnH-psbA trnS-trnG
Anathallis adenochila (Loefgr.)
F.Barros
A.L.V. Toscano de Brito 3357
(UPCB)
MN332331 MN332511 MN332420 - MN331573 MN307746
Anathallis articulata (Lindl.)
Luer & Toscano
A.L.V. Toscano de Brito 3845
(UPCB)
MW166880 MW166886 MW166902 MW166919 MW166894 MW166910
Anathallis gert-hatschbachii
(Hoehne) Pridgeon & Chase
A.L.V. Toscano de Brito 2913
(UPCB)
MN332345 MN332524 MN332433 MN332263 MN331585 MN307758
Anathallis obovata (Lindl.)
Pridgeon & Chase
A.L.V. Toscano de Brito 3240
(SEL)
MN332358 MN332534 MN332446 - MN331597 MN307768
Anathallis spiculifera (Lindl.)
Luer
A.L.V. Toscano de Brito 3843
(UPCB)
MW166881 MW166887 MW166903 MW166920 MW166895 MW166911
Barbosella australis (Cogn.)
Schlechter
M.E. Engels 392 (UPCB) MF669943.1 MF669949 MN332461 MN332286 MN331611 MN307782
Bletia catenulata Ruiz & Pavón A.V.S.R. Mauad 9 (UPCB) MN332374 MN332549 MN332463 MN332288 MN331613 MN307784
Brachionidium restrepioides
(Hoehne) Pabst
W.S. Mancinelli 1349 (UPCB) MN332375 MN332550 MN332464 MN332289 MN331614 -
Brachionidium valerioi Ames
& Schweinfurth
- (Pridgeon et al., 2001) AF262913 AF265488 - - - -
Cattleya coccinea Lindley -, T.F. Santos & M. Machnicki-
Reis 146 (UPCB)
AY008646 MN332551 MN332465 - MN331615 -
Cattleya forbesii Lindley E.C. Smidt 967 (UPCB) MN332376 MN332552 MN332466 MN332290 MN331616 MN307785
Dilomilis montana (Sw.)
Summerhayes
- (Pridgeon et al., 2001) AF262915 AF263765 - - - -
Dryadella lilliputiana (Cogn.)
Luer
W.S. Mancinelli 1065 (UPCB) MN332380 MN332556 MN332470 MN332294 MN331620 MN307788
Epidendrum armeniacum
Lindley
W.S. Mancinelli 1369 (UPCB) MN332381 MN332557 MN332471 MN332295 MN331621 MN307789
Epidendrum tridactylum
Lindley
G.F. Gonçalves 49 (SP) MN332382 MN332558 MN332472 MN332296 MN331622 MN307790
Lankesteriana caudatipetala
(C. Schweinf.) Karremans
A.L.V. Toscano de Brito 3277
(UPCB)
MN332384 MN332559 MN332474 MN332298 MN331624 MN307792
Lepanthes helicocephala
Reichenbach
M.R. Cabral 5 (UPCB) MN332387 MN332560 MN332477 MN332300 MN331627 MN307793
Lepanthopsis floripecten
(Rchb. f.) Ames
A.L.V. Toscano de Brito 2912
(UPCB)
MN332388 MN332561 MN332478 MN332301 MN331628 MN307794
Madisonia kerrii (Braga) Luer A.L.V. Toscano de Brito 2852
(SEL)
MN332389 MN332562 MN332479 MN332302 -MW166912
Myoxanthus lonchophyllus
(Barb. Rodr.) Luer
M.L. Klingelfus 187 (UPCB) MN332390 MK642625 MN332480 MN332303 MN331629 MN307795
Myoxanthus punctatus (Barb.
Rodr.) Luer
A.L.V. Toscano de Brito 2871
(UPCB)
KX686538 MK642626 MN332481 MN332304 MN331630 MN307796
Neocogniauxia hexaptera
(Cogn.) Schlechter
C. van den Berg 244 (K) AF260148 AF263766 - - - -
Octomeria gracilis Lodd. ex
Lindley
E.C. Smidt 947 (UPCB) MN332392 KX686527 MN332483 MN332306 MN331631 MN307797
......continued on the next page
SMIDT ET AL.
74 • Phytotaxa 505 (1) © 2021 Magnolia Press
TABLE 1. (Continued)
Taxon Voucher nrITS matK psbD-trnT rps16-trnQ trnH-psbA trnS-trnG
Octomeria grandiflora Lindley W.S. Mancinelli 1372 (UPCB) MN332393 MN332564 MN332484 MN332307 MN331632 MN307798
Pabstiella brasilica Luer &
Toscano
A.L.V. Toscano de Brito 3836
(UPCB)
MW166882 MW166888 MW166904 MW166921 MW166896 MW166913
Pabstiella brasilica A.L.V. Toscano de Brito 3842
(UPCB)
MW166883 MW166889 MW166905 MW166922 MW166897 MW166914
Pabstiella carrisii (Brade) Luer A.L.V. Toscano de Brito 3602
(UPCB)
MW166885 MW166892 MW166908 MW166925 MW166898 MW166917
Pabstiella carrisii M. Bolson 569 (UPCB) - MW166890 MW166906 MW166923 MW166899 MW166915
Pabstiella carrisii M. Bolson 572 (UPCB) MW166884 MW166891 MW166907 MW166924 MW166900 MW166916
Pabstiella mirabilis (Schltr.)
Brieger & Senghas
E.C. Smidt 921 (UPCB) MN332394 MN332565 MN332485 MN332308 MN331633 MN307799
Pabstiella yauaperiensis (Barb.
Rodr.) Barros
A.L.V. Toscano de Brito 3054
(UPCB)
MN332395 MN332566 MN332486 MN332309 MN331634 MN307800
Platystele edmundoi Pabst M.R. Cabral 4 (UPCB) MN332396 MN332567 MN332487 MN332310 MN331635 MN307801
Pleurothallis isthmica Luer A.L.V. Toscano de Brito 2945
(SEL)
MN332398 MN332569 MN332489 MN332311 MN331637 MN307803
Pleurothallis loranthophylla
Reichenbach
A.L.V. Toscano de Brito 2961
(SEL)
MN332399 MN332570 MN332490 - - -
Pleurothallopsis nemorosa
(Barb. Rodr.) Porto & Brade
A.L.V. Toscano de Brito 3414
(UPCB)
MN332400 MN332571 MN332491 MN332312 MN331638 -
Restrepia trichoglossa F. Lehm.
ex Sander
M.L. Klingelfus 117 (UPCB) MN332402 MN332573 MN332493 MN332314 MN331640 MN307804
Restrepiella ophiocephala
(Lindl.) Garay & Dunsterville
A.L.V. Toscano de Brito 3126
(SEL)
MN332403 MN332574 MN332494 MN332315 MN331641 MN307805
Sansonia bradei (Schltr.)
Chiron
M. Bolson 565 (UPCB) MN332404 MN332575 MN332495 MN332316 MN331642 MN307806
Scaphosepalum microdactylum
Rolfe
A.L.V. Toscano de Brito 2957
(SEL)
MN332405 MN332576 MN332496 MN332317 MN331643 -
Specklinia grobyi (Bateman ex
Lindl.) Barros
J. Klein 94 (UPCB) MN332406 MN332577 MN332497 MN332317 MN331644 MN307807
Specklinia ianthina Pessoa &
Barros
L. Guimarães s.n. (SP 491489) - MW166893 MW166909 MW166926 MW166901 MW166918
Stelis aprica Lindley M.E. Engels 1599 (UPCB) MN332407 MN332578 MN332498 MN332319 MN331645 MN307808
Stelis argentata Lindley A.L.V. Toscano de Brito 3377
(UPCB)
MN332408 MN332579 MN332499 MN332320 MN331646 -
Stelis ciliaris Lindley E.C. Smidt 960 (UPCB) MN332409 MN332580 MN332500 MN332321 MN331647 -
Stelis grandiflora Lindley E. Caglioni & C. Signorelli
288 (UPCB)
MN332410 MN332581 MN332501 MN332322 MN331648 MN307809
Stelis mystax (Luer) Pridgeon
& Chase
A.L.V. Toscano de Brito 2948
(SEL)
MN332391 MN332563 MN332482 MN332305 - -
Stelis papaquerensis
Reichenbach
W.S. Mancinelli 1341 (UPCB) MN332411 MN332582 MN332502 MN332323 MN331649 MN307810
Stelis ruprechtiana
Reichenbach
M.C. Santos et al. 14 (UPCB) MN332412 MN332583 MN332503 MN332324 MN331650 MN307811
Zootrophion atropurpureum
(Lindl.) Luer
A.B.R. Almeida 32 (HUCP) MN332413 - MN332504 MN332325 MN331651 MN307812
AN EXPANDED CONCEPT OF MADISONIA Phytotaxa 505 (1) © 2021 Magnolia Press • 75
Results
We analysed 263 DNA sequences, of which 51 (19,47%) are newly produced for this study (Table 1). Both phylogenetic
inferences produced similar topologies for the nrITS and cpDNA datasets available in supplementary material (S1).
Only the results from combined datasets are presented, the bootstrap percentages from both ML (MLBP) and MP
(MPBP) analyses (Fig. 1), and parsimony statistics for all datasets are given (Table 2).
FIGURE 1. Maximum-likelihood tree of the Pleurothallidinae emphasising the Madisonia clade. Numbers below branches represent
ML and MP bootstrap percentages ≥ 50, respectively. In detail, the ML tree with branch lengths. Red lines correspond to the Octomeria
affinity.
SMIDT ET AL.
76 • Phytotaxa 505 (1) © 2021 Magnolia Press
TABLE 2. Characteristics of each dataset, the results of heuristic searches with their respective indexes, and the best
substitution models according to AIC. VC = variable characters (percentage from total length), PIC = parsimony-informative
characters (percentage from VC), CI = consistency index, RI = retention index.
Dataset taxa Length
(bp)
VC PIC Trees
retained
steps CI RI Component
information
Model (AIC)
matK 48 1,065 402 (37.7%) 183 (45.5%) 3,240 735 0.65 0.69 0.82 K3Pu+F+R3
psbD-trnT 46 1,331 390 (29.3%) 177 (45.4%) 10,000 654 0.70 0.71 0.59 TIM+F+R3
rps16-trnQ 42 1,204 323 (26.8%) 113 (35.0%) 10,000 564 0.73 0.63 0.57 TIM+F+R2
trnH-psbA 43 1,258 316 (25.1%) 119 (37.6%) 9,941 542 0.73 0.63 0.61 TIM+F+R4
trnS-trnG 38 1,098 274 (25.0%) 118 (43.1%) 3,204 485 0.68 0.60 0.72 GTR+F+R3
cpDNA 49 5,956 1,705 (28.6%) 710 (41.6%) 10 3,181 0.65 0.59 0.91 Combined
nrITS 46 769 397 (51.7%) 276 (69.5%) 36 1,366 0.47 0.61 0.84 TIM3+F+I+G4
nrITS+cpDNA 49 6,725 2,102 (31.2%) 986 (46.9%) 4 4,603 0.59 0.58 0.95 Combined
Pleurothallidinae is retrieved as monophyletic (69 MLBP; and 80 MPBP), with the Dilomilis affinity highly
supported (100 MLBP; and 100MPBP) and sister to the rest (94 MLBP; and 52 MPBP) of the affinities and their genera.
The next clade, the Octomeria affinity, is weakly supported (88 MLBP; < 50 MPBP) and includes the Madisonia clade
(93 MLBP and 70 MPBP). The Madisonia clade is composed by Madisonia kerri and M. brasilica as sister clade of M.
carrisii, which is sister to M. spiculifera, M. bradei, M. articulata, and M. ianthina.
Except for Brachionidium, the other genera within Pleurothallidinae are retrieved in accordance with the
classification proposed by Karremans (2016). The recovered affinities have received moderate to strong support,
with Octomeria followed by Restrepia (95 MLBP; 76 MPBP), which is sister to the subsequent clade formed by the
affinities of Lepanthes (100 MLBP; 100 MPBP), Specklinia (96 MLBP; 93 MPBP), and Pleurothallis (100 MLBP; 99
MPBP).
Discussion
Madisonia kerrii and several morphologically similar species assigned to diverse genera in the Pleurothallidinae are
recovered in a well-supported clade sister to Octomeria. The generic concept of Madisonia is therefore expanded to
include genus Sansonia and miscellaneous species in Anathallis Barbosa Rodrigues (1877: 23), Pabstiella, Brieger &
Senghas (1976: 193) and Specklinia Lindley (1830: 8) (see section Taxonomy below). The close relationship among
most of these taxa had been suggested in previous taxonomic studies (Luer & Toscano de Brito 2012, Karremans 2016,
Karremans et al. 2016), and is now confirmed based on DNA evidence from both nuclear and plastid sequences.
The re-circumscription of Madisonia implies the recognition of a poorly understood but well-supported, early-
diverging lineage in the Pleurothallidinae. It is widespread throughout the Caribbean and the Guyanas, the Amazon,
and the Atlantic Forest in South America. Madisonia kerrii, an Amazon endemic (Luer 2006), is closely related to M.
spiculifera, which occurs from Jamaica and Trinidad and Tobago to northern Brazil (Luer 2006, Silva & Silva 2010),
and to several Atlantic Rainforest endemics most of which are restricted to narrow geographic ranges in the Brazilian
states of Bahia, Rio de Janeiro, and São Paulo. These distribution patterns within Madisonia constitute an important
basis for future biogeographical hypotheses for the past connection between the Atlantic Rainforest and the Amazon,
and may have implications in the estimate of the origin of the Pleurothallidinae (Pérez-Escobar et al. 2017, Gutiérrez
Morales et al. 2020).
Our results are compatible with the Pleurothallidinae genera classification into affinities proposed by Karremans
(2016). Although not definite, genus Madisonia seems to belong in the Octomeria affinity. The position of Brachionidium
is the only divergence from the Karremans (2016) classification and the only supported incongruence between our
ML and MP results. This incongruence may be due to long-branch attraction (Felsenstein 1978, Bergsten 2005,
AN EXPANDED CONCEPT OF MADISONIA Phytotaxa 505 (1) © 2021 Magnolia Press • 77
Kolaczkowski & Thornton 2009) and the limited taxon sampling. Both Pérez-Escobar et al. (2017), using a broader set
of species, and Serna-Sánchez et al. (2021), using extensive genomic data from plastomes, find Brachionidium placed
together with Octomeria at the base of the subtribe. Madisonia was not included in either and further DNA-based
studies focusing on these early-divergent lineages in the subtribe are needed to confidently establish the relationships
between these genera and adequately assess their biogeographical patterns.
A taxonomic revision of Madisonia may increase the number of species currently accepted for the genus. Population
studies are needed to establish whether broadly distributed taxa, such as Madisonia spiculifera, truly represent a single
species. A detailed morphological analysis should focus on the segmented, creeping rhizome, the trilobed lip, and the
number of pollinia, key features to distinguish Madisonia from other pleurothallid genera.
Taxonomy
Genus Madisonia is re-circumscribed to accommodate species previously assigned to Anathallis, Pabstiella,
Specklinia, and Sansonia. A morphological characterisation, distribution and synopsis of the genus and its nine species
are presented below.
Madisonia Luer (2004: 258).
TYPE:—Madisonia kerrii (Braga) Luer (2004: 258). Fig. 2, 3.
Basionym: Pleurothallis kerrii Braga (1981: 172).
Etymology:—Named in honour of Michael Madison, co-collector of the type specimen.
Plants small, epiphytic or rupicolous, long-repent; rhizome slender, segmented between the ramicauls, nodes with
ribbed, slightly ciliate sheaths. Ramicaul shorter than the leaf, enclosed by 1–2 ribbed, more or less ciliate sheaths.
Leaf decumbent to erect, cuneate below a short petiole, broadly elliptical to lanceolate, minutely tridenticulate to
apiculate, thick to coriaceous. Inflorescence a successively few-flowered raceme, shorter or longer than the leaf.
Flower resupinate or not, dark-red to purple, glabrous; dorsal sepal lanceolate to oblong, lateral sepals connate at least
to the middle, adnate to the column-foot, sometimes forming a mentum; petals linear to oblong; lip oblong to ovate,
trilobed, disc generally smooth, with or without callosities, lateral lobes erect, apical lobe acute to rounded, smooth,
pilose or irregular; column semiterete usually bidentate at the apex, anther subapical, stigma ventral.
Distribution:—Know to occur in Trinidad and Tobago and Jamaica in the Caribbean, the Amazon from Bolivia,
Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname and Venezuela, and the Brazilian Atlantic
Rainforest.
1. Madisonia articulata (Lindl.) Toscano & Smidt, comb. nov.
Basionym: Pleurothallis articulata Lindley (1842: 83).
Homotypic synonyms: Humboltia articulata Kuntze (1891: 667). Anathallis articulata (Lindl.) Luer & Toscano (2009: 257).
Distribution: Brazil, originally described from an unknown locality. A recent collection (Toscano de Brito 3845–UPCB) made in the
municipality of Una, Bahia state, confirms the presence of this species in the Atlantic Rainforest.
2. Madisonia bradei (Schltr.) Toscano & Smidt, comb. nov.
Basionym: Physosiphon bradei Schlechter (1922: 39).
Homotypic synonyms: Sansonia bradei (Schltr.) Chiron (2012: 82). Phloeophila bradei (Schltr.) Garay (1974: 117). Pleurothallis
neobradei Luer (1986: 17). Specklinia neobradei (Luer) Luer (2004: 262).
Distribution: Brazil, São Paulo and Espírito Santo, Atlantic Rainforest (Schlechter 1922, Chiron 2012).
3. Madisonia brasilica (Luer & Toscano) Toscano & Smidt, comb. nov.
Basionym: Pabstiella brasilica Luer & Toscano (2012: 310).
Homotypic synonym: Pleurothallis brasilica (Luer & Toscano) Pfahl (2013: 1).
Distribution: Brazil, Bahia, Atlantic Rainforest (Luer & Toscano de Brito 2012, Rêgo & Azevedo 2017).
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FIGURE 2. Illustration of Madisonia kerrii (Braga) Luer. A. Habit. B. Detail of the habit. C. Resupinated flower in lateral view. D.
Dissected perianth. By Stig Dasltröm based on Luer 17019.
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FIGURE 3. Photographs of Madisonia kerrii (Braga) Luer. A. Habit. B. Detail of the habit. C. Detail of the flower in natural position. By
Gustavo Romero based on Romero 3371.
4. Madisonia carrisii (Brade) Toscano & Smidt, comb. nov. Fig. 4.
Basionym: Pleurothallis carrisii Brade (1951: 75).
Homotypic synonym: Pabstiella carrisii (Brade) Luer (2007: 119).
Specklinia carrisii (Brade) Luer (2004: 259).
Distribution: Brazil, Rio de Janeiro (Brade 1951) and Espírito Santo, municipality of Santa Teresa (Bolson 569, 572–UPCB), Atlantic
Rainforest.
5. Madisonia gomesii-ferreirae (Pabst) Toscano & Smidt, comb. nov.
Basionym: Pleurothallis gomesii-ferreirae Pabst (1975: 53).
Homotypic synonyms: Pabstiella gomesii-ferreirae (Pabst) Luer (2007: 119). Stelis gomesii-ferreirae (Pabst) Pridgeon & Chase (2001:
263). Specklinia gomesii-ferreirae (Pabst) Luer (2004: 260).
Distribution: Brazil, Pernambuco, Atlantic Rainforest.
Although we have been unable to obtain specimens of Pleurothallis gomesii-ferreirae for inclusion in our phylogenetic
analyses, we do not hesitate to add this taxon to our list of Madisonia species. The tiny plants possess an elongate,
articulate rhizome, which is ca. 1 cm long between ramicauls; the leaf is erect, linear-lanceolate, 1–1.5 cm long; the
inflorescence is erect, ca. 3 cm long; the flower is minute and patent; the sepals are ca. 5 mm long, the lateral sepals
almost entirely connate to near the apex to form a synsepal; the lip is oblong, trilobed, rounded and obtuse, with lateral
lobes erect and placed slightly above the middle of the lip.
6. Madisonia ianthina (E.M.Pessoa & F.Barros) Toscano & Smidt, comb. nov.
Basionym: Specklinia ianthina Pessoa & Barros (2014: 131).
Distribution: Brazil, Bahia, Atlantic Rainforest (Pessoa & Barros 2014).
Karremans et al. (2016) included Specklinia ianthina under the synonymy of Pabstiella brasilica. Our results show
that they are not closely related species, despite the morphological and geographical proximity.
SMIDT ET AL.
80 • Phytotaxa 505 (1) © 2021 Magnolia Press
FIGURE 4. Lankester Composite Dissection Plate of Madisonia carrisii (Brade) Toscano & Smidt. A. Habit. B. Flower. C. Dissected
perianth. D. Column and lip, lateral view. E. Lip. F. Column, ventral view. G. Anther cap and pollinarium.
AN EXPANDED CONCEPT OF MADISONIA Phytotaxa 505 (1) © 2021 Magnolia Press • 81
7. Madisonia kerrii (Braga) Luer. Figs. 2, 3.
Basionym: Pleurothallis kerrii Braga (1981: 172).
Distribution: Northern Brazil, Colombia (Cárdenas-López 24034 (COAH)), Peru, and Venezuela, Amazon Rainforest (Luer 2006, Betancur
et al. 2015).
8. Madisonia spiculifera (Lindl.) Toscano & Smidt, comb. nov.
Basionym: Pleurothallis spiculifera Lindley (1859: 43).
Homotypic synonym: Humboltia spiculifera (Lindl.) Kuntze (1891: 668).
Specklinia spiculifera (Lindl.) Pridgeon & Chase (2001: 259).
Anathallis spiculifera (Lindl.) Luer (2009: 259)
Distribution: Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Jamaica, Suriname, Trinidad and Tobago and Venezuela. It
inhabits moist broadleaf forests including the Amazon Rainforest (Luer 2006, Silva & Silva 2010, Koch et al. 2014, Betancur et al.
2015).
9. Madisonia vandenbergii (Chiron) Toscano & Smidt, comb. nov.
Basionym: Sansonia vandenbergii Chiron (2012: 85).
Homotypic synonym: Pleurothallis vandenbergii (Chiron) Shaw (2014: 77).
Distribution: Brazil, Bahia, Atlantic Rainforest (Chiron 2012).
We have been unable to obtain samples of Sansonia vandenbergii to include in our phylogenetic analyses. We follow
Chiron (2012) and Chiron et al. (2016) who found this species to be related to S. bradei.
Acknowledgements
We thank the anonymous reviewers whose comments were valuable for improving our study. E.C.S. was supported by
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for Bolsa de Produtividade em Pesquisa CNPq-
Nível 1D [grant number 314642/2020-0]. A.V.S.R.M. and N.G.M. was supported by Coordenação de Aperfeiçoamento
de Pessoal de Nível Superior (CAPES). A.L.V.T.B. thanks Wade Collier for revising the English, and for his friendship,
companion, and assistance in the field and in the herbarium during the last twelve years; Stig Dasltröm for inking the
line drawings; and Gustavo A. Romero for the images of M. kerrii. We thank Instituto Chico Mendes de Conservação
da Biodiversidade (ICMBio) [Process 30642-1; 50482-1, 50482-2] for the collection authorizations.
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SUPPLEMENTARY MATERIAL. Maximum-likelihood tree of the Pleurothallidinae emphasizing the Madisonia clade.
Numbers on nodes represent ML bootstrap percentages ≥ 50. A. Tree from nrITS data. B. Tree from plastid data (matK,
psbD-trnT, rps16-trnQ, trnH-psbA, and trnS-trnG).
