Three new species of Pleurothallis (Orchidaceae: Pleurothallidinae) in subsection Macrophyllae-Fasciculatae from northern South America

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Pleurothallis tenuisepala, a new species in subsection Acroniae, is described and compared to Pleurothallis luctuosa with which it has previously been confused. While the two species are superficially similar, they can be very easily distinguished by the size of the flowers, which are approximately 60 mm long in P. tenuisepala versus approximately 29 mm long in P. luctuosa, or the length of the sepals, which are approximately four-times the length of the petals in P. tenuisepala versus less than twice the length of the petals in P. luctuosa. The two species can also be discriminated by their nuclear internal transcribed spacer (nrITS) sequences. Pleurothallis tenuisepala occurs on Isla Gorgona off the Pacific coast of Colombia and on the western slopes of the Cordillera Occidental of the Colombian Andes, while P. luctuosa is restricted to the Cordillera de Tilarán of Costa Rica. Labellar micromorphology of both species is discussed in relation to possible pollination mechanisms.resuMen. Se describe Pleurothallis tenuisepala, una nueva especie en la subseccción Acroniae, y se compara con Pleurothallis luctuosa, con la cual ha sido previamente confundida. Aunque las dos especies sean superficialmente similares, pueden ser fácilmente reconocidas por el tamaño de las flores, que miden aproximadamente 60 mm de longitud en P. tenuisepala versus cerca de 29 mm en P. luctuosa, así como por la longitud de los sépalos, que son aproximadamente cuatro veces más largos de los pétalos en P. tenuisepala, mientras que en P. luctuosa miden menos que el doble de los pétalos. Las dos especies pueden discriminarse también por las secuencias de su región espaciadora interna nuclear (nrITS). Pleurothallis tenuisepala se encuentra en la Isla Gorgona, frente a la costa pacífica de Colombia y en la vertiente occidental de la Cordillera Occidental de los Andes colombianos, mientras que P. luctuosa está restringida a la Cordillera de Tilarán de Costa Rica. Se discute la micromorfología del labelo de ambas especies en relación a posibles mecanismos de polinización.

Section: Resultsmentioning

confidence: 99%

Hidden in plain sight: a new species of Pleurothallis (Orchidaceae: Pleurothallidinae) from Colombia previously misidentified as Pleurothallis luctuosa

Wilson¹,

Zhao²,

Hampson³

et al. 2019

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“…In none of the observations of living plant material or numerous photographs of the three species have we ever seen any evidence of a liquid nectar-like reward. Nor did SEM indicate the presence of even a vestigial nectary or "glenion" as occurs in Pleurothallis subsections Macrophyllae-Fasciculatae (Wilson et al 2016) and Acroniae (Wilson unpubl. data), or any other possible secretory tissue (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…The labella of P. talpinaria, P. trimeroglossa and the new species were compared in detail by stereo-microscopy, macro-photography and SEM. Flowers for SEM were prepared as described previously (Wilson et al 2016).…”

Section: Methodsmentioning

confidence: 99%

“…These scant field observations are being supplemented by micro-morphological studies of the labellum using scanning electron microscopy (SEM), which can be used to hypothesize putative pollination mechanisms for future field testing. While a preliminary study of labellar morphology of species in Pleurothallis subsection Macrophyllae-Fasciculatae (Wilson et al 2016) has been published, this represents the first study of the labellar morphology in the P. talpinaria group.…”

Section: Introductionmentioning

confidence: 99%

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A clarification of the distinctions between Pleurothallis talpinaria and Pleurothallis trimeroglossa (Orchidaceae: Pleurothallidinae) and an allied new species from Ecuador

Wilson

Baquero

Driessen³

et al. 2017

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aBstract. Pleurothallis trimeroglossa has long been considered a synonym of P. talpinaria. In this study we reviewed types, descriptions, drawings, paintings and living material for both names and concluded that P. talpinaria and P. trimeroglossa should be recognized as distinct species. An anatomical structure important in the distinction between the two is the large dome-shaped callus at the base of the lip in P. trimeroglossa. The approximate distributions and elevational ranges of the two species are discussed. During the study we recognized a novel species, described here as Pleurothallis jostii. Labellar morphology of all three species was examined. We speculate on the pollination mechanism of this group of species based on the observations of labellar micro-morphology.

“…Whilst the phylogenetic relationships among the different subsets of species artificially gathered in this study is not granted, they can nevertheless be easily distinguished as a group from other assemblages of taxa. Informally circumscribed, this group includes some 35 species, distributed from Costa Rica to Peru and Bolivia, with the highest diversity recorded in the northern Andes of Colombia and Ecuador (Luer 2005, Wilson et al 2016.…”

mentioning

confidence: 99%

Two new species of Pleurothallis (Orchidaceae: Pleurothallidinae) from Costa Rica in the P. phyllocardia group

Pupulin

Díaz-Morales²,

Fernández³

et al. 2017

abstract. Two new species of Pleurothallis subsection Macrophyllae-Fasciculatae from Costa Rica are described and illustrated, and their relationships discussed. Pleurothallis pudica, from the central Pacific mountain region, is compared with P. phyllocardia, but it is easily recognized by the densely pubescenthirsute flowers. Pleurothallis luna-crescens, from the Caribbean slope of the Talamanca chain, is compared with P. radula and P. rectipetala, from which it is distinguished by the dark purple flowers and the distinctly longer, dentate petals, respectively. A key to the species of the group in Costa Rica and western Panama is presented.