Classification ofAthyrium and allied genera of Japan

The classification ofAthyrium sensu lato is revised on the basis of evidence from anatomical and morphological observations. Although parallelism is found in several characteristics, stipe base, groove of frond axis, laminar margin, venation, sorus and dermal appendage are important to classify the genus and elucidate the relationship within it.Athyrium sensu lato is divided into four generaAthyrium, Cornopteris, Deparia andDiplazium, small genera being referred toAthyrium orDiplazium, Deparia is construed in a broad sense to includeAthyriopsis, Dryoathyrium andLunathyrium. The four genera with infrageneric groups or sections are described in detail. Among the genera,Athyrium, particularly theA. puncticaule group, may be considered to have primitive characteristics, andCornopteris may have been derived fromAthyrium by abortion of the indusia.Cystopteris is also related toAthyrium on the basis of reniform sori inC. douglasii.