Phenotypic Variations in Mt. Hamiquitan Ferns as Revealed by Multivariate Techniques

In situ morphological characterization, using 23 qualitative and 21 quantitative morphological traits subjected to Principal Components Analysis (PCA) and Cluster Analysis, was carried out to determine the phenotypic relationships and diversity of 55 fern species documented in Mt. Hamiguitan, Lupon, Davao Oriental and identify the underlying causes of phenotypic variability exhibited by these fern species. PCA reduced the 44 characters into 12 principal components which cumulatively explained 79.9% of total variance observed and clustered the ferns into groups based on discriminant traits such as length of lateral pinnae (LLP), width of blade (WB), receptacle position (RP) and true indusium (TI). Cluster analysis using UPGMA and UPGMC further revealed similar groupings and trends. Both trees showed the divergence of 3 fern species (Sticherus hirtus (Bl.) Copel., Dipteris conjugata Reinw. and Cyathea sp.) and the morphological homogeneity of the rest of the fern species. Moreover, UPGMA outperformed UPGMC in terms of classifying the fern species into functional groups on the basis of dissimilarity. This study predating molecular diversity analysis has demonstrated the functionality of this low-level taxonomic tool when used in conjunction with powerful multivariate statistical techniques.