Vegetative morphological variation in Chamaedorea elatior (Arecaceae), a first approach at species delimitation

Background and aims – Chamaedorea is the largest genus of neotropical palms distributed mainly in lowland rainforests and montane cloud forests from Mexico to Bolivia. Species delimitation in this genus remains problematic due to high morphological variation and inconsistent taxonomic treatment of such variation. Chamaedorea elatior, a climbing species from southern Mexico and northern Central America, exemplifies these challenges with several historical synonyms and informally recognized morphotypes. This study evaluates the morphological variation in vegetative characters between this species’ most characteristic two morphotypes, cespitose and solitary, to evaluate their taxonomic distinctiveness. Material and methods – Six populations of C. elatior were sampled in Mexico and Guatemala, representing both solitary and cespitose morphotypes. Thirteen morphological leaf characters were measured from mature individuals. Data were examined using univariate and multivariate analyses (NMDS, k-means clustering, PCA, MANOVA, LDA) to evaluate morphological variation between the morphotypes and populations. Discriminant analyses were also used to assess classification into either morphotype. Key results – Univariate analyses revealed significant differences between morphotypes in most measured characters, mainly those associated with leaf size. Similarity analyses recovered both morphotypes as being distinct from each other. PCA showed notable separation of the morphotypes along the first component that summarized leaf and median leaflet size. Both MANOVA and LDA confirmed significant differences between morphotypes and resulted in high accuracy classification. Conclusion – Leaf morphology clearly distinguishes the solitary and cespitose morphotypes of C. elatior, supporting their potential delimitation as separate species. The branching habit of the cespitose form further reinforces this distinction. While current results support species-level recognition, additional evidence from reproductive characters, niche, and genetic divergence is recommended to confirm a possible species delimitation.