Ameiotic Alternation of Generations: A New Life Cycle in the Ferns

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Science  17 Jan 1964:
Vol. 143, Issue 3603, pp. 261-263
DOI: 10.1126/science.143.3603.261


The fern Polypodium dispersum Evans (ined.) has a completely somatic alternation of generations. During sporogenesis the sporophyte exhibits 111 unpaired chromosomes, 16 spore mother cells, and 32 viable diplospores. The sporophyte arises by proliferation from a gametophyte lacking sex organs. This is the first completely documented report of this type of life cycle in the ferns.