The morphology of phytoliths for tropical pteridophytes in southwestern China

Phytolith analysis of pteridophytes (ferns and lycophytes) is significant for reconstructing paleoenvironments and understanding their evolutionary histories. However, current research on phytoliths in extant pteridophytes remains scarce compared to these for angiosperms. This study focused on the highly diverse pteridophytes in Xishuangbanna, a tropical region in East Asia, and 20 species from 16 genera of pteridophytes were collected for this study. The morphology and production of their phytoliths were observed in detail, and a statistical analysis was conducted. Results revealed significant differences in both the production and morphology of phytoliths among species. Nine genera were identified as typical phytolith producers, with a total of 27 distinct morphotypes. We also identified potential diagnostic morphotypes of phytolith with taxonomic significance in 10 species. Among them, EPIDERMAL OVATE ORNATE and CYLINDRICAL VERRUCATE exhibited distinct characteristics and were produced in high quantities within plants, making these phytoliths the most promising morphotypes for classification. Meanwhile, the phytolith data encompassing 258 pteridophyte species was amassed in the present study. This study increased new information on the morphology of pteridophyte phytoliths in tropical regions, thereby offering pivotal insights for the utilization of pteridophyte phytoliths in research fields such as taxonomy, archaeology, and paleoecology.