Pleurothallis mark-wilsonii a new species from the subsection Acroniae series Amphigyae from the Western Andes of Colombia

Abstract

A new species of Pleurothallis from the Western Andes of Colombia is described and illustrated. The new species belongs to subsection Acroniae of the series Amphigyae, morphologically resembles Pleurothallis amphigya, but differs mainly by the ovate-lanceolate lip, with two divergent, elongate keels, located at the base up to about the middle of the lip (vs. triangular trilobed, the disc with a developed glenion at the base).

Full text

Phytotaxa 568 (3): 283–288
https://www.mapress.com/pt/
Copyright © 2022 Magnolia Press Article PHYTOTAXA
ISSN 1179-3155 (print edition)
ISSN 1179-3163 (online edition)
Accepted by Edlley M. Pessoa: 10 Oct. 2022; published: 18 Oct. 2022
https://doi.org/10.11646/phytotaxa.568.3.5
283
Pleurothallis mark-wilsonii a new species from the subsection Acroniae series
Amphigyae from the Western Andes of Colombia
JUAN SEBASTIÁN MORENO1,2,7*, MARIO ALEXEI SIERRA-ARIZA2,3,8, DAVID HOYOS4,5,9 & ROBINSON
GALINDO-TARAZONA4,10
1Departamento de Biología, Universidad del Valle, Calle 13 # 100-00, Cali, Colombia.
2Grupo de Investigación Schultes, Fundación Ecotonos, Valle del Cauca, Cali, Colombia.
3Grupo de investigación en Biodiversidad y Dinámica de Ecosistemas Tropicales (GIBDET), Universidad del Tolima, Ibagué, Colombia.
4Grupo de Investigación en Recursos Naturales Amazónicos – GRAM, Facultad de Ingenierías y Ciencias Básicas, Instituto Tecnológico
del Putumayo – ITP, Mocoa, Putumayo, Colombia.
5Herbario Etnobotánico del Piedemonte Andino Amazónico HEAA, Instituto Tecnológico del Putumayo – ITP, Cra 17 14-85
(Corpoamazonia), Mocoa, Putumayo, Colombia.
6Parques Nacionales Naturales de Colombia, Dirección Territorial Pacífico, Carrera 117 # 16B-00, Cali, Colombia.
7
�
juan.moreno.silva@correounivalle.edu.co; https://orcid.org/0000-0003-4325-1232
8
�
mrsierraariza80@gmail.com; https://orcid.org/0000-0002-5148-08717
9
�
david_076-@hotmail.com; https://orcid.org/0000-0002-2339-9478
10
�
rgtgalindo@gmail.com; https://orcid.org/0000-0003-1081-9418
* Author for corresponde
Abstract
A new species of Pleurothallis from the Western Andes of Colombia is described and illustrated. The new species belongs to
subsection Acroniae of the series Amphigyae, morphologically resembles Pleurothallis amphigya, but differs mainly by the
ovate-lanceolate lip, with two divergent, elongate keels, located at the base up to about the middle of the lip (vs. triangular
trilobed, the disc with a developed glenion at the base).
Keywords: San José del Salado, systematics, taxonomy, Valle del Cauca
Introduction
Pleurothallis Brown (1813: 211), is a neotropical genus with distribution from western Mexico to South America,
with some representation in the Caribbean islands (Doucette et al. 2016). It is represented by 499 species (Karremans
& Vieira-Uribe 2020), excluding new species that have been published in the last two years (e.g. Jiménez et al. 2021,
Sierra-Ariza et al. 2022, Vélez-Abarca et al. 2022).
The species within Pleurothallis subsect. Acroniae ser. Amphigyae Luer (1998: 5) are distinguished by its
caespitose habit with well-developed ramicauls that are usually longer than the leaf and carries a terminal inflorescence
of a single long-pedunculated flower; the flowers could be distinguished by completely connate lateral sepals that form
a synsepal similar to the dorsal sepal; the petals are prominent, membranous, and mostly broad, frequently descending
and sigmoid in outline, and often ciliate, denticulate, fringed, or pubescent; the lip is generally triangular to trilobed,
lateral lobes more or less curved or erect and not prolonged, its base is variously deflected below lateral lobes and
articulated at base of foot of column; the semiterete column, usually short, bears an apical anther and a stigma that is
transverse or bilobed, and the ovoid pollinia have a tiny viscidium (Luer 1986, 1998).
In 2015 and 2017 five new species of Pleurothallis were described from the mountains of San José del Salado, in
the department of Valle del Cauca (Rodríguez-Martínez et al. 2015, Karremans et al. 2017) and from this same area we
found a new species of Pleurothallis from the subsection Acroniae series Amphigyae, that we here described, illustrate
and compare with the most similar species.

MORENO ET AL.
284 • Phytotaxa 568 (3) © 2022 Magnolia Press
FIGURE 1. Pleurothallis mark-wilsonii J.S.Moreno, Gal-Tar & Sierra-Ariza. A. Habit. B. Flower. C. Dissected perianth.
D. Column and lip, lateral view and longitudinal section of the column. E. front and side view of lip. F. Column,
ventral and side view. Drawing by J.S. Moreno based on the holotype.

A NEW PLEUROTHALLIS FROM COLOMBIA Phytotaxa 568 (3) © 2022 Magnolia Press • 285
Taxonomy
Pleurothallis mark-wilsonii J.S.Moreno, Gal-Tar & Sierra-Ariza, sp. nov. (Figures 1–2).
Type:—COLOMBIA. Valle del Cauca: Municipio de Dagua, Corregimiento de San José del Salado, 1750 m, August 2020, R. Galindo-T
& D.L. Mora 3927 (holotype: CUVC!).
Pleurothallis mark-wilsonii is most similar to P. amphigya Luer & Escobar (1981: 128) but could be distinguished
its petals oblong-lanceolate, revolute and strongly acuminate (vs. elliptical-ovate or subsigmoid, oblique and slightly
acuminate) and the lip ovate-lanceolate, with two diverging keels, elongated, located at the base to near the middle of
the lip (vs. triangular trilobed, the disc with a developed glenion at the base).
Description:—Plant epiphytic, caespitose, medium-sized herb to 17 cm tall. Roots slender, ca. 1.5 mm in
diameter. Ramicauls terete, suberect, slender, 3–12 cm long, 1.2–2.2 mm in diameter, pale green, provided with tubular
sheaths, short and truncated up to 2.5 cm long at the base, the bracts brown, papyraceous. Leaf suberect, coriaceous,
rigid, sessile, elliptical-ovate, acute, slightly acuminate, 4–6 × 2–3.5 cm. Inflorescence, a fascicle of single-flowered
peduncles, is born from a reclined spathaceous bract, lanceolate, 0.8 mm long, brown, papyraceous and fibrous when
mature, eventually dissolving with age. Ovary straight, striate, papillate, 6–15 mm long. Flowers beige with vinaceous
colored microdots, on the lip the dots are much larger and more visible. Dorsal sepal ovate-lanceolate, concave at the
base, very involute forming a tube, acute, long-attenuate, 30–35 × 8–13 mm, 3 veined. Lateral sepals connate into
a narrow ovate-lanceolate synsepal, concave at the base, very involute forming a tail, acute, long-attenuate, 38–40 ×
6–9 mm, 4 veined. Petals oblong-lanceolate, downward inclined, revolute, ciliate, vesiculose to the base, strongly
acuminate, 17–20 × 2–4 mm, 3 veined. Lip triangular, trilobed, curved at the basal part when viewed laterally, irregular,
salient margins, acuminate, 3.2–3.5 × 2.5–2.8 mm, with two diverging keels, elongated, located at the base to near the
middle of the lip. Column semiterete, ventrally vesiculose, stigma apical, prominent margins, 2.8 × 1.5 mm. Anther
cap broadly ovate, pale yellow, 2-celled, ca. 0.8 mm long. Pollinia two, narrowly oblong, pyriform, 0.9 mm long,
attached to an elliptic viscidium. Fruits not seen.
Distribution and ecology:—The species is apparently endemic to the Western Andes in Colombia in the
department of Valle del Cauca. It has been found growing as an epiphyte on an Andesanthus lepidotus (Humboldt &
Bonpland 1808: 38) Guimarāes & Michelangeli (2019: 948) (Melastomataceae) wood fence at 50 cm from the ground
along the edge of a pasture in close proximity to a very well-preserved forest.
Additional specimens examined (paratype):—COLOMBIA. Valle del Cauca: Municipio de Dagua,
Corregimiento de San José del Salado, Altos de San José del Salado, 1860 m, July 2016, J.S.Moreno & A.L. Erazo 493
(CAUP!).
Etymology:—Named after Mark Wilson from the Colorado College in USA. A friend and an arduous researcher
of the genus Pleurothallis. His contributions have provided valuable information to solve several taxonomic difficulties
within the genus (Figure 3)
Taxonomic Discussion:—Pleurothallis mark-wilsonii belongs to the P. subsect. Acroniae ser. Amphigyae (Luer
1998). The most morphologically similar species is probably Pleurothallis amphigya with purple flowers (vs. beige
and white flowers with vinaceous dots in the lip and petals), the petals elliptical-ovate or subsigmoid, oblique and
slightly acuminate (vs. oblong-lanceolate, revolute, downward inclined and strongly acuminate) and a lip triangular
trilobed, the disc with a well-developed glenion at the base (vs. curved at the basal part when viewed lateral, irregular,
salient margins, acuminate, with two diverging keels, elongated, located at the base to near the middle of the lip). From
Ecuador, Pleurothallis thoerleae (Luer 2012: 337) in Shaw (2016: 39) also from the series Amphigyae is similar to the
new species but the latter has rose purple sepals and light yellow-orange petals (vs. beige and white sepals and petals
with vinaceous dots), petals linear and gradually acuminate into filamentous tail (vs. oblong-lanceolate and downward
inclined and strongly acuminate) finally the lip light-yellow thickly 3-lobed, with the apex broadly rounded with
an abrupt apiculum at the center of the margin and the disc with a central pair of rounded parallel calli (vs. ovate-
lanceolate, acuminate, with the apex acuminate with two diverging keels, elongated, located at the base to near the
middle).

MORENO ET AL.
286 • Phytotaxa 568 (3) © 2022 Magnolia Press
FIGURE 2. Pleurothallis mark-wilsonii J.S.Moreno, Gal-Tar & Sierra-Ariza. A. Habit. B. Flower. C. Dissected perianth. D. Column and
lip, lateral view and longitudinal section of the column. E. front and side view of lip. F. Column, ventral and side view. Anther cap and
pollinia. LCDP by J.S. Moreno based on the holotype.

A NEW PLEUROTHALLIS FROM COLOMBIA Phytotaxa 568 (3) © 2022 Magnolia Press • 287
FIGURE 3. Photograph of Mark Wilson.
Acknowledgements
The first author is especially grateful to José Otocar Reina and his son Juan Fernando Reina for their company and
hospitality in the Altos of San José del Salado. We would like to thank Humberto Dominguez Escobar from El Carare
Natural Reserve for allowing us to explore his property in San José del Salado (Dagua) and Argemiro Vargas Rodriguez
for providing access to his territory in El Limonar (Dagua, Valle del Cauca). To Fundación Grupo Conserva for its
logistical support. DH highlights the effort of Instituto Tecnológico del Putumayo for its funding to research. The
authors are very grateful to Danny Leandro Mora for his support during the field trips to the areas of San José del
Salado where the new species was found.

MORENO ET AL.
288 • Phytotaxa 568 (3) © 2022 Magnolia Press
References
Brown, R. (1813) Clasis XX. Gynandria-Monandria. Hortus Kewensis; or, a Catalogue of the Plants Cultivated in the Royal Botanic
Garden at Kew 5: 188–220.
Doucette, A., Wilson, M., Portilla, J., Kay, A., Moreno, J.S. & Cameron, K.M. (2016) Two new species of Pleurothallis and a new name
for Acronia rinkei. Orquideología 33: 123–139.
Guimarāes, P.J.M. & Michelangeli, M.A. (2019) Systematics of Tibouchina and allies (Melastomataceae: Melastomateae): A new
taxonomic classification. Taxon 68: 937–1002.
https://doi.org/10.1002/tax.12151
Humboldt, F.H.A. & Bonpland, A.J.A. (1808) Monographie des Melastomatacées, Rhexies. De L’imprerie de J. Smith, Paris, 160 pp.
Jiménez, M., Ocupa Horna, L. & Vélez-Abarca, L. (2021) Anew species of Pleurothallis (Orchidaceae: Pleurothallidinae) from Zamora in
the Province of Zamora Chinchipe, Ecuador. Phytotaxa 518: 79–86.
https://doi.org/10.11646/phytotaxa.518.1.11
Karremans, A.P., Rodriìguez-Martiìnez, L. & Rincoìn-Useche, C. (2017) Four new species of Pleurothallis (Orchidaceae: Pleurothallidinae)
from The Valle del Cauca Department in Colombia. Lankesteriana 17: 251–260.
https://doi.org/10.15517/lank.v17i2.30155
Karremans, A.P. & Vieira-Uribe, S. (2020) Pleurothallids: Neotropical jewels, vol I. Mariscal, Quito, 320 pp.
Luer, C.A. & Escobar, R.R. (1981) Miscellaneous new species in the Pleurothallidinae (Orchidaceae). Orquideología 14: 114–187.
https://doi.org/10.5962/bhl.part.15137
Luer, C.A. (1986) Icones pleurothallidinarum III. Systematics of the genus Pleurothallis (Orchidaceae). Monographs in Systematic Botany
from the Missouri Botanical Garden 20: 1–108.
Luer, C.A. (1998) Icones Pleurothallidinarum XVII: Subgenus Pleurothallis (Orchidaceae). Monographs in Systematic Botany from the
Missouri Botanical Garden 72: 1–63.
Luer, C.A. (2012) Miscellaneous new species in the Pleurothallidinae (Orchidaceae). Harvard Papers in Botany 17: 333–368.
https://doi.org/10.3100/025.017.0214
Rodriìguez-Martiìnez, L., Rincoìn-Useche, C. & Karremans, A.P. (2015) A New Pleurothallis from Colombia, with a Note on Ancipitia
and Colombiana (Orchidaceae: Pleurothallidinae). Systematic Botany 40: 75–78.
https://doi.org/10.1600/036364415X686350
Shaw, J.M.H. (2016) Quarterly supplement to the international register and checklist of orchid hybrids (Sander´s List), January – March
2016 Registrations. The Orchid Review 124: 1–40.
Sierra-Ariza, M.A., Rincón-González, M., Wilson, M. & Villanueva, B. (2022) Una nueva especie de Pleurothallis (Pleurothallidinae)
subsección Macrophyllae-Fasiculatae para la región Andina Colombiana. Lankesteriana 22: 25–35.
https://doi.org/10.15517/lank.v22i1.50823
Vélez-Abarca, L., Jiménez, M.M., GutiérreZ, D. & Baquero, L.E. (2022) Pleurothallis ariana-dayanae, a new species in subsection
Macrophyllae-Fasiculatae (Pleurothallidinae) from the Cordillera del Condor, Ecuador. Lankesteriana 22: 101–109.
https://doi.org/10.15517/lank.v22i2.51750