Anatomy of Tandilia Range Ferns from Argentina: Identifying Diagnostic Traits and Ecological Adaptations

Background and aims: The Tandilia Range in the Pampean Plain of Argentina is a key center of fern diversity in the region. However, anatomical information about the main species is scarce. The aim of the present study was to characterize and compare the leaf blade anatomy and petiole anatomy of six species of native ferns from the Tandilia Range and identify diagnostic features to develop an identification key and recognize ecological adaptations. M&M: Anemia tomentosa, Blechnum auriculatum, Doryopteris triphylla, Haukia crotalophoroides, Rumohra ponceana, and Physematium montevidense were collected. Cross-sections of frond were made. Measurements of some epidermal characters were carried out, and comparisons between species were performed via generalized linear mixed models. Results: The epidermal cells of the pinnae in most of the studied species presented walls with sinuous-wavy edges. Anomocytic were the most frequent stomatal type. Glandular trichomes in A. tomentosa, B. auriculatum, D. triphylla, R. ponceana and P. montevidense were identified. The presence of multiple epidermis, circumendodermal band, epidermal papillae, conical stegmata, and aerophores in the petiole base were detected in some of the species. Conclusions: This is the first anatomical characterization of native ferns from the Tandilia Range. These findings provide valuable information for species identification and may support future ecological research