Is the labellum informative to distinguish species of Scaphyglottis(Orchidaceae)? Insights from geometric morphometrics

Hiding in the Atlantic Forest: Leaf geometric morphometrics redefines endangered Aristolochia (Aristolochiaceae) sibling species and allows conservation strategies

“…The "Tps" software series (e.g. Nery & Fiaschi 2019;Karbstein et al 2020;Pessoa et al 2020;Cheng et al 2021;Danila & Alejandro 2021;Araújo et al 2023) and the MorphoJ (e.g. Pessoa et al 2020;Guamba et al 2021;Danila & Alejandro 2021;Araújo et al 2023) have been used in several GM studies with plants.…”

“…Plant morphometrics allows the assessment of pattern variation at low cost, provides consistent results, and helps solving taxonomic uncertainties at both species and population levels (Marhold 2011;Turco et al 2022). Geometric Morphometrics (GM) has been applied to assess leaf (Cheng et al 2021;Danila & Alejandro 2021;Guamba et al 2021) and/or flower quantitative variation to distinguish species (Fragoso-Martínez et al 2015;Menini-Neto et al 2019;Freitas et al 2020b;Guamba et al 2021;Pessoa et al 2020;Araújo et al 2023), by identifying homologous points across samples, called landmarks, and comparing the format of each one of the structures in its entirety (Christodoulou et al 2020). Linear morphometrics, on the other hand, uses only measurable values, such as length and width, not considering the shape (Christodoulou et al 2020).…”

Vanilla pompona Schiede: Morphological variation of the labellum in localities of Veracruz, Puebla, Jalisco and Oaxaca, Mexico

“…(These groups should consist of 12 to more than 30 replicates [46,47]). Recently, studies have been carried out in orchids based on morphometric analysis of flowers where CVA is used to differentiate between species of the genus Epidendrum [48], to delimit the species Trichocentrum cepula, T. caatingaense and T. sprucei [49], and to distinguish species of the genus Scaphyglottis [36]. On the other hand, principal component analysis (PCA) is used to reduce dimensions and explore the overall structure of the database according to Wickens [50] and Lattin et al [44], and is performed based on the correlation matrix between the selected variables [51].…”

“…In the study of morphological variation of orchid flowers, it is important to use an integrated approach, with classic taxonomy [20] and also morphometric analysis of the labellum, as has been used in different orchid species, for example, to differentiate between species of the genus Scaphyglottis [36]; and differentiate between Dryadella edwallii Luer, D. wuerstlei Luer and D. zebrina Luer [37]. The evaluation includes the morphological variation of Pseudolaelia vellozicola Hoehne populations [38] and populations of Pseudorchis straminea Fernald and P. albida Á.Love and D.Love [39].…”