Pleurothallis chicalensis, a new species in subsection Macrophyllae Fasciculatae (Orchidaceae: Pleurothallidinae) from northwestern Ecuador
A new species of Pleurothallis in subsection Macrophyllae Fasciculatae from Ecuador is described, illustrated and its relationship with other species is discussed. Pleurothallis chicalensis is compared with P. dewildei, from which is distinguished by the ovate leaves, the yellow flowers with broadly obovate synsepal and the transversely cordate lip with apiculate apex. resuMen. Una especie nueva de Pleurothallis de la subseccion Macrophyllae Fasciculatae de Ecuador es descrita, ilustrada y su afinidad con otras especies es discutida. Pleurothallis chicalensis se compara con P. dewildei, de la cual difiere por las hojas ovadas, las flores amarillas con el sinsepalo ampliamente obovado y el labelo transversalmente cordado con el apice apiculado. key Words: Andes, Carchi, Pleurothallis bovilingua, Pleurothallis dewildei, taxonomy Received 22 January 2018; accepted for publication 31 May 2018. First published online: 20 July 2018. Licensed under a Creative Commons Attribution NonCommercial NoDerivs 3.0 Costa Rica License doi: https:/doi.org/10.15517/lank.v18i2.34050 Introduction. In the genus Pleurothallis R.Br. sensu Pridgeon et al. (2005) there are between 478 and 625 species (Wilson unpubl. data) depending on synonymy, making it the third largest genus in Pleurothallidinae, after Lepanthes Sw. and Stelis Sw. The genus is distributed from Central America and the Caribbean Islands to South America, where most of the species are epiphytes in cloud forests of the Andes (Doucette et al. 2016) Section Macrophyllae Fasciculatae Lindl. was created as part of Pleurothallis infrageneric classification by Lindley (1859) which was later considered by Luer (1986) in his initial systematics of genus Pleurothallis and subsequently demoted to a subsection of the same name (Luer 1988) However, in 2005 he resurrected the genus Acronia C.Presl, grouping the subsections Acroniae (C.Presl) Luer and Macrophyllae Fasciculatae (Lindl. Luer (Luer 2005) Recently, phylogenetic relationships of Pleurothallis have been evaluated from DNA sequence analysis (Pridgeon et al. 2001, Wilson et al. 2011, 2013, unpubl. data) The studies revealed the close relationship of subsection MacrophyllaeFasciculatae with the type species Pleurothallis ruscifolia (Jacq. R.Br. that supports the inclusion of this group within Pleurothallis versus Acronia (Wilson et al. 2016) Luer (2005) in revision of subsection Macrophyllae Fasciculatae indicated that members of the group are distinguished by their sessile leaves with a cordate base, single flowers with lateral sepals connate into a synsepal, and a bilobed stigma. Since