Abstract
Autotetraploid Osmunda banksiifolia (2n=4x=88) was produced by induced apospory for the first time. The sizes of guard cells and mature spores showed the differences between the autotetraploid and the diploid sporophytes (p<0.01). The spematozoids of 2x antheridia were also larger than those of x antheridia (p<0.01). The meiotic chromosome configuration of the autotetraploid sporophyte showed univalent, bivalent and multivalent chromosomes at metaphase I and lagging chromosomes were frequently observed at both anaphase I and anaphase II. Among 30 spores one showed to be unreduced. From the 4x gametophyte 8x sporophytes could not be produced in O. banksiifolia.
