New Species of Pleurothallis (Orchidaceae: Pleurothallidinae), a New Country Record, and Labellar Morphology in the P. cardiostola-P. lilijae Complex of Subsection Macrophyllae-Fasciculatae

Abstract. Pleurothallis subsection Macrophyllae-Fasciculatae is the most species-rich infrageneric grouping within this genus. Within this subsection, based on floral and vegetative morphology, we recognize the P. cardiostola-P. lilijae complex, an expansion of Luer's previously proposed subsection Cardiostolae. The nature of the two species P. cardiostola and P. lilijae is clarified here to allow comparison to an additional 24 possible members of the complex. Recognizing P. lanigera as distinct from P. cardiostola, and the other putative species as distinct from each other, brings the complex of previously described species to 26. In the process of reviewing living material and photographs of these species, as well as of the many plants misidentified as P. lilijae, it quickly became apparent that there are multiple undescribed species in this group. Six new species from Colombia, Ecuador and Peru are described herein. Each species is typified, described and illustrated, in most cases with a drawing, a composite digital plate, photos to show floral variability, and a scanning electron micrograph of the lip. Including these additional 6 species brings the P. cardiostola-P. lilijae complex to 32 members, which is both more numerous and more widely distributed than the P. cardiothallis-P. titan complex. One characteristic of species in this group is the copious production of nectar-like liquid on the lip and a prominent glenion.