Spore Morphology of Platycerium (Polypodiaceae) and Its Implications

The spore characteristics of ferns play an important role in taxonomy; however, comprehensive spore data for most species of the genus Platycerium remain scarce. In this study, spores of Platycerium were examined using light microscopy and scanning electron microscopy. We established the first comprehensive dataset on spore morphology in Platycerium. Based on morphological characteristics, we classified the spores into four distinct types, each described in detail. Spore surface ornamentation proved to be an effective diagnostic feature for Platycerium coronarium, P. madagascariense, P. ridleyi, and P. stemaria. The systematic significance of spore morphology in Platycerium was discussed, while no significant linear correlation was found across Platycerium between spore sizes and genome sizes. Our findings are important for understanding the relationship between spores and ploidy levels in Polypodiaceae and their evolutionary implications.