Taxonomic Significance of Venation Pattern in Pyrrosia

The characteristics of the venation patterns of 17 species of Pyrrosia (Platycerioideae, Polypodiaceae) were studied using anatomical methods. Venation characteristics of eight species in eight genera of three subfamilies of Polypodiaceae were provided for comparative study. The results showed that the anatomizing venation patterns of Pyrrosia included campyloneuroid and pseudo-drynarioid type, which differed from other anastomosing patterns observed in Polypodiaceae based on morphological phylogenetic analysis. Venation patterns are relatively stable traits in classification, and can be used as a stable taxonomic characteristic in Pyrrosia. Based on the venation pattern and other anatomic evidence, the relationships of venation pattern among P. piloselloides M. G. Price Kalikasan and P. angustissima (Giesenh. ex Diels) Tagawa & K. lwats. with Pyrrosia are discussed.