The choice is that a less effective one in the chemical characteristics of cytokinin seems to be more suitable for this purpose. This is similar to the findings reported by Higuchi et al. (1987) for Nephrolepis cordifolia Presl and by Higuchi and Amaki (1989) for Asplenium nidus. We found 2.22 มิวM 2ip with 5.37 มิวM NAA to be a better combination to accomplish these tow goals( sporophyte depressing and diameter increasing) than could be expected from the addition of BA to the medium (Table 4). However, for long-term maintenance or subculturing of pure GGB tissues without sporophyte regeneration, BA might be the best choice.