Herein, Diplazium maonense Ching is confirmed to grow in Taiwan. The morphological description and a key to related Diplazium spp. are provided. The chromosome number of the sporophyte was counted 123 which indicates it is a triploid. The spore number per sporangium is 32. The first young frond is pinnate. All these characteristics indicate that its sporophytes are reproduced through apogamy.