Drynaria quercifolia is an epiphytic fern often exposed to water- and light-stressed environments. One distinct ecophysiological adaptation of epiphytic ferns is their symbiotic relationship with fungi. This is the first study undertaken to explore the phylogenetic relationship, colonization, occurrence rate, and diversity of RSF found in D. quercifolia. Two hundred seventy-eight RSF isolates were collected from 300 representative root segments. Genomic DNA of the RSF was extracted, and the ITS (internal transcribed spacer) region of the 18S ribosomal DNA (rDNA) was sequenced. Thirteen species were recorded. Eight of the 13 RSF were identified up to the species level using the Basic Local Alignment Search Tool nucleotide search program (BLASTn) to their closest type match available on the databank of NCBI. However, five RSF were undescribed.