Cytological and reproductive studies on Japanese Diplazium (Woodsiaceae; Pteridophyta):: Apomictic reproduction in Diplazium with evergreen bi- to tripinnate leaves

Mitotic and meiotic chromosomes were examined in a total of 162 plants representing 16 taxa in the Japanese Diplazium, including polymorphic terrestrial species with evergreen bi- to tripinnate leaves. Diplazium hachijoense, D. virescens var. virescens, var. conterminum, var. okina waense, and two other unnamed varieties, D, kawakamii var, kawakamii, D, dilatatum var. heterolepia, D. taiwanense, D. x kawabatae (=D. dilatatum X taiwanense), D,X takii (=D, hachijoense x virescens var. virescens), and D. x nakamurae (=D, hachijoense X virescens var. conterminum) are apomictic triploids (2n=n=123), Diplazium amamianum and D. esculentum are sexual diploids (2n= 82, n=41) and D, subtripinnatum is a sexual tetraploid (2n=164,n=82), Diplazium dilatatum var. dilatatum includes both sexual diploid and apomictic triploid populations. Cultivated gametophytes of six triploid taxa produced sporophytes apogamously, confirming their apomictic reproduction. All three putative hybrids, D.Xkawabatae, D.xtakii, and D.Xnakamurae, are triploid, apomictic, and fertile taxa, therefore they are not the result of hybridization between known pairs of Japanese Diplazium plants.