Taxonomic Studies of the Diplazium mettenianum Complex (Woodsiaceae; Pteridophyta) in Japan: Morphology, Cytology and Taxonomy of Plants with Normal-Shaped Spores

complex, including two polymorphic species D. mettenianum and D. griffithii, with normal-shaped spores collected from 62 sites. An analysis of 20 qualitative morphological characters showed that the complex can be divided into five forms. A statistical analysis of 16 quantitative morphological characters supported the distinctness of five forms which are regarded as independent species: D. mettenianum, D. fauriei, D. deciduum nom. nov. (=D. mettenianum var. tenuifolium), D. griffithii, and D. hayatamae sp. nov. A cytological study on 150 plants showed that D. deciduum and plants in a single population of D. fauriei are sexual hexaploids (2n=6x=246=123ll), and all others are sexual tetraploids (2n=4x=164=82ll).