The flora of Myanmar was extensively documented by British botanists and plant hunters in the early nineteenth century. Dickason (1946) reported 460 species of lycophytes and ferns belonging to 104 genera, and listed 140 species as first records for Myanmar. Before that time, only a few lycophytes and ferns had been collected in Myanmar and enumerated sporadically as part of the exploration of flowering plants. Of the 460 species Dickason (1946) reported, 125 are found on the Malay Peninsula, which is south of 6.5^°N. However, most of his collections had been disappeared because of a lack of adequate maintenance in Myanmar. Moreover, no one until recent times has studied ferns in the country because the literature is insufficient and there are few herbarium specimens; most botanists who have studied in Myanmar have worked solely on flowering plants (Angiosperms). In 2005–2008, Thet Yu New (2009) studied the fern diversity of Kyaik-Hti-Yoe Wildlife Sanctuary, reporting 68 species belonging to 46 genera and 19 families. These included 12 species new to Myanmar: Araiostegia imbricata Ching, Bolbitis copelandii Ching ex C. Chr. & Tard., Crypsinus cruciformis (Ching) Tagawa, Crypsinus ebenipes (Hook.) Copel., Doryopteris concolor (Langst. et Fisch) Kuhn, Elaphoglossum malayense Holtt., Davallia trichomanoides Bl., Humata vestita Bl., Lemmaphyllum carnosum (Hook.) Presel., Microlepia strigosa (Thunb.) Kaulf., Microsorum scolopendrium (Burm. f.) Copel., and Pleocnemia irregularis (C. Presl) Holttum. At about the same time, Fraser-Jenkins (unpubl. data) made a list of 599 taxa of lycophytes and ferns after examining and re-identifying early collections from Myanmar kept in the Royal Botanic Gardens Kew (K), British Museum of Natural History (BM), and University of Michigan Herbarium (MICH), as well as his new collections from Myanmar (unpubl. data). However, our knowledge of the lycophytes and ferns of Thailand and Vietnam, each of which has in excess of ca. 600–700 species (Alston et al., 1939–1951; Tagawa and Iwatsuki, 1979, 1985, 1988, 1989; Boonkerd et al., 2004) led us to predict that many more than the 599 species reported by Fraser-Jenkins (unpubl. data) occur in Myanmar.

Natma Taung National Park in southern Chin State, western Myanmar, was established in 1994 and is located at 21^°12′ N, 93^°35′ E, close to the border with India and Bangladesh (Fig. 1). It covers around 723 km² of the Chin Hills and contains the highest peak in southern and central Myanmar: Mt. Natma Taung (Mt. Victoria, elevation 3,051 m). Natma Taung National Park has diverse vegetation that includes a secondary forest consisting mainly of pine and alder near the ridge in Kanpetlet Township situated at an altitude of 1,200 m, a dipterocarp forest dominated by Dipterocarpus and Shorea on the slopes lower than 1,000 m, pine forest on dry ridges and plateaus near the border of the National Park lying at about 1,800 m, oak forests occupying the moist valleys on southern slopes further up, and a laurel and stone oak forest on the northern slopes up to about 2,500 m. The summit of Natma Taung is open meadow (Fujikawa et al., 2009).

Several scientific explorations involving collaboration between the Forestry Department of Myanmar and Japanese botanists (Fujikawa et al., 2009, 2012, 2013) have examined in the Natma Taung National Park, although their activities have focused solely on flowering plants and no inventories of ferns have been conducted. Therefore, we tried to examine the species composition of ferns inhabited in the Natma Taung National Park. The results provide an update to the checklist of ferns of Myanmar.