Resumen de La filotaxis en Osmundales (Filices) fósiles
The phyllotaxis of the fossil Osmundales (Filices). An analysis of fossil and recent stems ofOsmundales is carried out to establish their phyllotaxis. A practical method proposed by Erasmus is used andthus examples of at least 8 genera and 32 species, based mainly on specimens depicted in the literature, aregiven. It may be concluded that in this group of ferns only phyllotactical conditions of 5/13, 8/21, 13/34, 21/55and 34/89 are present with a clear dominance of those of 13/34 and 21/55 in fossils while extant species onlyshow 8/21 phyllotaxis.
