Abstract: The object of this paper is to deal with the taxonomical problems of the family Aspidiaceae from the mainland of Asia. In recent years I have had the opportunity to study copious materials of the family from this region, and recognized the following nine genera, namely, Lastreopsis Ching, Ctenitis C. Chr., Ctenitopsis Ching, Pleocnemia Presl, Arcypteris Underw., Tectaria Cavanilles, Quercifilix Cop., Hemigramma Christ and Pteridrys C. Chr. et Ching. The members of this family are middle-sized, terrestrial ferns; rhizome erect or suberect, dictyostelic, scaly; leaves tufted, generally uniform, simple pinnate to tripinnatifid; veins free or anastomosing, forming areoles with or without free included veinlets; rachis and costa raised on the upper surface, and, as a rule, covered with pale brown multicellular articulate hairs (ctenitis-hairs); sori round or in a few cases acrostichoid; indusia reniform, or in some genera absent; spores bilateral with perispore. Dryopteridaceae and Lomariopsidaceae are closely related to Aspidiaceae, and both were placed in the latter family by the fern students in the past. The main differences of Dryopteridaceae from Aspidiaceae are: leaves pale green when dried; costa and costule grooved and free from articulate hairs (ctenitis-hairs) on the upper side; veins free or very rarely anastomosing (venatio cyrtomii). In general appearance the genus Ctenitis of Aspidiaceae is very similar to the bipinnate species of Dryopteridaceae, such as Dryopteris filix-mas (Linn.) Schott, but its costa and costule are raised and covered by ctenitis-hairs on the upper side, and the leaves turning dull brown when dried, so that it has no difficulty in distinguishing the genus from the true Dryopteris. The recognition of the free-veined Ctenitis and its allies as the primitive tectarioid ferns is very important in delimiting both Aspidiaceae and Dryopteridaceae, which were all mixed up in the past. Moreover, from the standpoint of plant geography, these two families are also distinct, for the Dryopteridaceae are mainly ferns of the temperate regions and the mountains in subtropics in the Northern Hemisphere, but the Aspidiaceae are pantropical by origin. The chief differences of Lomariopsidaceae from the Aspidiaceae are: rhizome creeping or high-climbing; leaves strongly dimorphous, free from the ctenitis-hairs; sori acrostichoid. That Holttum has made Aspidiaceae a subfamily Tectarioideae of the family Dennstaedtiaceae proves to be very unnatural, because there is hardly any affinity between the two families; while Aspidiaceae of Copeland is a terrible mixture of Thelypteridaceae, Athyriaceae, Dryopteridaceae and Aspidiaceae (sen. strict.) and a few other families, for even he himself admitted that no one can use the definition to identify any unknown members of his family. Finally, I feel grateful to my teacher, Professor R. C. Ching, for his constant encouragement and warm guidance received both in the course of my study and in the prepara-tion of the present paper.