Cytological and Reproductive Studies on Japanese Diplazium (Woodsiaceae; Pteridophyta): Apomictic Reproduction in Diplazium with Evergreen Bi- to Tripinnate Leaves

Diplazium , including polymorphic terrestrial species with evergreen bi- to tripinnate leaves. Diplazium hachijoense, D. virescens var. virescens, var. conterminum, var. okinawaense, and two other unnamed varieties, D. kawakamii var. kawakamii, D. dilatatum var. heterolepia, D. taiwanense, D. × kawabatae (=D. dilatatum × taiwanense), D. × takii (=D. hachijoense × virescens var. virescens), and D.× nakamurae (= D. hachijoense × 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. × kawabatae, D. × takii, and D. × nakamurae, are triploid, apomictic, and fertile taxa, therefore they are not the result of hybridization between known pairs of Japanese Diplazium plants. Received 16 March 1999/ Accepted in revised form 30 September 1999