A taxonomic revision of genus Phloeophila ( Orchidaceae , Pleurothallidinae ) in Ecuador

. The orchid genus Phloeophila is distributed from southern Mexico to Brazil and Bolivia, as well as Cuba. A taxonomic revision including the three Phloeophila species present in Ecuador is presented. Morphological characteristics, an identification key, maps of known localities and illustrations of the species are also included. In Ecuador, species of Phloeophila are only known from the Amazonian rainforests, growing from 890 to 1600 meters of altitude. Phloeophila condorana is described as a new species based on specimens collected in the Ecuadorian province of Zamora-Chinchipe and compared to Phloeophila nummularia . Phloeophila nummularia is reported for the first time in Peru. A lectotype for Pleurothallis echinantha is selected.


Introduction
The subtribe Pleurothallidinae with more than 5000 species is considered the most diverse in species of all orchids and is currently divided in nine major clades (Karremans 2016). Phloeophila is a small genus of the Pleurothallidinae with three species distributed throughout Tropical America from Mexico, Central America, the Antilles, to Bolivia and Brazil (Karremans & Vieira-Uribe 2020).
The first Phloeophila collections were made in the late 19th century by Charles Wright (1859, Cuba) ( Fig. 1), Joao Barbosa Rodrigues (Brazil) and Friedrich Lehmann (Colombia). In 1865, Reichenbach described the first species attributable to Phloeophila as Pleurothallis nummularia based on material collected by Wright. In 1926, Hoehne and Schlechter established the genus with two species: P. echinantha and P. paulensis, designating the latter as the type species (Luer 2006). Subsequently, Garay (1974) included new taxa from different Pleurothallidinae lineages in the genus (López, Solano & Pérez-Farrera 2007). Later, in his taxonomic study of Pleurothallis Luer (1986) considered Phloeophila as a section of subgenus Acianthera (Chiron et al. 2016;López et al. 2007). In 2006, Luer changed his opinion bringing back Phloeophila as a genus encompassing four species (Luer 2006). Pridgeon et al. (2001), on the basis of DNA analysis, found that the species of Phloeophila form a monophyletic clade together with the species previously placed in Luerella and Ophidion. They subsequently combined these three groups into a broader circumscription of Phloeophila (Pridgeon & Chase 2001). Chiron et al. (2016) maintained this circumscription of Phloeophila from Pridgeon & Chase (2001). Recently, Karremans & Vieira-Uribe (2020) on the basis of molecular analysis of Chumová, Ponert and co-workers (Chumóva et al. 2018;Ponert et al. 2019) and considering the lack of diagnostic features in the broad Phloeophila, reestablished the genera mentioned before to their original concept, transferred P. oricola from Cuba to Acianthera and considered the Mesoamerican P. peperomioides as a synonym of the Brazilian P. echinantha.
Hitherto, a total of two species have been registered in Ecuador: Phloeophila nummularia, and P. ursula (Luer 2006(Luer , 2004. A color photograph of the holotype of P. ursula was included in the book Native Ecuadorian Orchids IV (Dodson 2003). During exploration aimed to determine part of the orchid diversity of the Cordillera del Cóndor in southeastern Ecuador, a new species of Phloeophila was discovered and is described here.
Considering that Phloeophila is a poorly morphologically known genus with cryptic species, without any previous taxonomic revisions in Ecuador, the present study aims: (1) To determine and circumscribe the genus in Ecuador by means of a taxonomic treatment.
(2) To synthesize the taxonomy and the circumscription of the Ecuadorian species of the genus based on data of the geographical distribution, the study of living and herbarium material of plants in flower and description of new taxa.

Materials and methods
Plants of the species examined in this study were collected under permit N°021-2019-IC-FLO-FAU-DPAZCH-UPN-VS / MA granted by the Ministerio del Ambiente of Ecuador. The material collected in the field was illustrated, preserved as exsiccata and stored in 70% ethanol and glycerine. Living specimens are cultivated by the Vivero de Conservación La Paphinia in Zamora and were photographed using a Panasonic ® FZ300 camera and a Raynox DCR-150 50 mm lens. Measurements were based on photos with a 30 cm ruler and using the ImageJ processing program (National Institutes of Health) downloaded from https://imagej.nih.gov/ (Lind 2012). Original descriptions from holotypes of related species (Luer 1996(Luer , 2006 were consulted and compared. The ArcMap program in ArcGIS (ESRI) was employed to produce the distribution maps of described species of Phloeophila in Ecuador and the new species (Fig. 4). Species collection localities were obtained from Luer (2006).

Distribution. Known only from Ecuador.
Etymology. The specific name refers to the Cordillera del Cóndor, an important mountain range in southern Ecuador renowned for its high biological diversity.
Habitat and ecology. This species has been reported for the Cordillera del Cóndor of the Zamora Chinchipe Province in Ecuador. Phloeophila condorana occurs as an epiphyte on tree trunks and branches of Dacryodes peruviana (Fig. 3), Schefflera sp. and Chrysophyllum sanguinolentum in premontane forests of a sandstone plateau. The elevation ranges from 893 to 1210 m elevation. In nature, P. condorana blooms from April to September.
The colors of the flowers are also distinct. P. condorana has pale yellow dorsal sepal with cinnamon-brown stripes, and lateral sepals suffused with red (vs whitish gray dorsal sepal with reddish purple stripes and the lateral sepals pale yellow-brown), the petals have yellow stripes (vs brown stripes), the lip is suffused with red and yellow (vs brownish yellow with purple marks) and the column is yellow (vs yellowish brown with stripes).
The new species is also similar to Phloeophila ursula, a restricted endemic species from the Morona-Santiago province in Ecuador. This taxon differs by the larger plants and flowers, the densely pubescent ovary and sepals, the narrowly elliptic dorsal sepal, the obovate synsepal which is connate near the middle, the oblong petals, the ovatetrilobed lip and the column foot pubescent (Luer 2006). Furthermore, all three species have been reported in southeastern Ecuador, Phloeophila condorana has been found growing in sympatry with P. nummularia at lower elevations from 890 to 1210 m in the Zamora-Chinchipe Province; while, according to Luer (2006), P. ursula grows in higher altitudes around 1600 m in the nearby province of Morona-Santiago. No intermediate specimens of P. condorana and P. nummularia have been found at the location where they grow together, suggesting that both species might have their individual pollinators.
Phloeophila condorana could be considered a restricted endemic species because it has not been found in other localities in Ecuador. Because the populations of the new species are not protected for any kind of conservation initiative and are mainly threatened by the abundant mining activity, the species may be considered as near threatened (NT) according to IUCN criteria (IUCN 2012). More research will be conducted to get awareness of populations of P. condorana in the adjacent areas.
Distribution. Cuba, Ecuador, Peru, Bolivia and Brazil. Habitat and ecology. In Ecuador, this species has been reported for the Cordillera del Cóndor in Zamora Chinchipe Province. It was also reported by Luer (2006) from the specimen Hirtz 4807 collected near Tena. Phloeophila nummularia is found as an epiphyte on tree trunks of Dacryodes peruviana (Fig. 3)   Notes. Phloeophila nummularia is considered as a widely distributed species from Cuba, Ecuador, Bolivia, to the south of Brazil (Luer 2006). This geographical distribution with three areas far away from each other is unusual. It is assumed P. nummularia will occur in Venezuela and Colombia when a better exploration of the Amazon is carried out. This species is recorded for the first time here for Peru from a specimen collected in the department of Huánuco.
In Luer's (2006) monograph of Specklinia and vegetatively similar taxa, three line illustrations of morphotypes were included. One of them, collected by Alexander Hirtz in northeastern Ecuador, was mistakenly labelled as from Bolivia which in fact corresponds to a specimen characterized by having longer peduncle and pedicel. This morphotype is also illustrated here (Fig. 6). The same occurs with the specimen from Ecuador corresponding to a collection from Bolivia.

Distribution. Known only from Ecuador.
Habitat and ecology. This species has been only reported for the Chigüinda surrounding area in the Morona-Santiago province, Ecuador. Phloeophila ursula grows apressed upon the mossy bark of the trees (Luer 1996).
Etymology. From the Latin ursula, 'a bear cub', in allusion to the pubescent vegetative and floral parts.
Notes. In this study, no living material of Phloeophila ursula was collected. This species is similar to P. nummularia, but is distinguished by the proportionally larger flowers, the dorsal sepal considerably smaller than the lateral sepals, the petals minutely verrucose at the apex and the apical half of the lip, denticulate and verrucose (Luer 1996).