New seed morphological features in Moehringia L. (Caryophyllaceae) and their taxonomic and ecological significance

Seeds of 27 species of Moehringia and four related representatives of Arenaria (old M. sect. Pseudomoehringia) were examined by scanning electron microscopy. Novel morphological features were observed in addition to those found in a previous similar study. The new information thus obtained provided new insight into the taxonomic value of discrete morphological characters considered in a recent phylogenetic context. Main Moehringia sections are undoubtedly defined by different types of strophioles, and by the corresponding testa cell features. This study also shows the different ontogenesis of hilar appendages previously attributed to Iberian taxa, now belonging to Arenaria. In addition to phylogenetic differences, ecology seems to play a role in the differentiation of seed morphological features with clear convergences among plants living on cliffs.