Gametophytic phase of the Indonesian ferns Amblovenatum immersum (Blume) Mazumdar and Christella subpubescens (Blume) Holttum (Thelypteridaceae)

The gametophytic generation of Amblovenatum immersum and Christella subpubescens (Thelypteridaceae), including spore germination, morphological development of the gametophytes, major vegetative features and reproduction strategies, was studied. For both species, the spore germination was of the Vittaria type and the developmental pattern was of the Drynaria type. Adult gametophytes were cordate and hairy, with unicellular and secretory hairs located in the margins and both the ventral and dorsal surfaces of the prothalli. C. subpubescens has another type of acicular hairs only in the margin of the prothallus. Gametangia were of the normal type described for leptosporangiate ferns. In A. immersum all the gametophytes were female. In C. subpubescens the gametophytes produced at first instance female gametangia and then became bisexual with time. Antheridiogen activity was observed in both species, suggested by the presence of small young ameristic gametophytes with antheridia surrounding well-developed female ones.