Taxonomic classification of Philippine Eria sensu lato (Eria Lindl., Mycaranthes BI. and Trichotosia BI.) (Orchidaceae: Eriinae) species inferred from morpholoical, physiological, and ecological data

Over the years of reclassification within Orchidaceae, Eria Lindl. has been taxonomically ambiguous based on morphological and molecular studies. Mycaranthes Bl. and Trichotosia Bl. were originally established as genera but subsequently subsumed within Eria as sections. Eventually, recent taxonomic efforts resurrected these two genera at generic level. However, the taxonomic classification of Philippine Eria, Mycaranthes, and Trichotosia species remain unassessed. Herbarium and collected specimens of native Eria, Mycaranthes, and Trichotosia were meticulously examined and analyzed using clustering and principal component analyses. Generally, stem hair color and presence of hair on inflorescence, lateral sepals, dorsal sepal, and pedicelled ovary circumscribed the three genera based on morphological analysis. Carbon isotope discrimination was conducted to characterize the photosynthetic strategy of the species. Philippine Trichotosia was found to exhibit C3 and Facultative CAM photosyntheses. A maximum entropy (Maxent) modeling approach was performed to predict potential suitable niches for Philippine Eria, Mycaranthes, and Trichotosia species based on occurrence records and environmental variables. Each taxonomic group obtained distinct combination of environmental conditions that greatly influenced their predictive species distribution. A total of two Eria species, twelve Mycaranthes, and nine Trichotosia species were herein recognized. Numerous nomenclatural novelties, specifically one new species, four reinstated names, and one new combination, were presented. Extensive photosynthetic characterization is needed to determine photosynthetic strategy can separate the species. Molecular approach may be conducted to reassess the morphological, physiological, and ecological findings