The Kinabalu flora includes about 5000 species of vascular plants, of which some 12% are ferns. They occur from the lowest elevations to the highest and in every conceivable habitat. The first fern specimens from the mountain were obtained by Hugh Low in 1851, and they have been actively collected ever since. The inventory of ferns published in 1992 (Parris, Beaman & Beaman) included 593 taxa (excluding the Lycopodiaceae and Selaginellaceae, which are no longer considered fern allies). The checklist in this volume notes 590 taxa. Some species have been added, others removed, and the names of others changed as a result of progress in knowledge of fern relationships. The 100 species, subspecies and varieties described and illustrated in this guide comprise about 17 percent of the Kinabalu ferns, including members of all 29 families, and 64 of the 135 known genera are represented. Includes a glossary and index to scientific names.