Formosan rhododendron (Rhododendron formosanum Hemsl.) is an endemic species of Erica-les in Taiwan. The Rf28 fungal strain was isolated from the roots of Formosan rhododendron and identified as an endophytic species of Phialocephala based on its morphological characteristics. This identification was further supported by a DNA sequence analysis. This species is a new addition to the fungal flora of Taiwan. In ericoid-mycorrhizal synthesis, Rf28-inoculated Formosan rhododendron seedlings exhibited vigorous growth, and an examination of the root ultrastructure revealed the occurrence of hyphal complexes and hyphal coils in cortical cells. These results demonstrated that Formosan rhododendron can form ericoid mycorrhiza in vitro with Phialocephala spp. 台灣杜鵑為台灣原生種杜鵑科植物。本研究自台灣杜鵑根系分離純化杜鵑類內生菌Rf28菌株，並以其ITS1-F/TW13序列與基因庫已知的杜鵑類內生菌資料比對，鑑定為Phialocephala菌株，此種真菌為台灣絲孢菌類新紀錄種。以Rf28菌株接種台灣杜鵑無菌苗再合成菌根試驗發現，菌根合成苗生長良好，且自其根部皮層細胞的微細構造中發現具有菌絲複合體和菌絲圈，此結果證實Phialocephala spp.內生菌能與台灣杜鵑形成典型的杜鵑類菌根。
