The colonization of land by vascular plants is an extremely important phase in Earth’s life history. This key evolutionary process is thought to have begun during the Middle Cambrian1 period and culminated in the Silurian/Early Devonian period (interval about 509–393 million years ago (Ma)), and is documented primarily by microfossils (that is, by dispersed spores, phytodebris including fragments of algae, tissues, sporangia and cuticles), tubes and rare megafossils2. A newly recognized fossil cooksonioid plant with in situ spores from the Barrandian area, Czech Republic, is of the highest importance because it represents extremely ancient megafossil evidence of land plant diploid generation: sporophytes (~432 Ma). The robust size of this plant places it among the largest known early polysporangiate land plants and it is probable that it attained adequate size for both aeration and effective photosynthetic competence. This would mean not only that sporophytes were photosynthetically autonomous but also that the they might have been able to sustain a relatively gametophyte-independent existence.
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We acknowledge financial support from the Grant Agency of Czech Republic, First vascular land plants and palynomorphs from the Silurian–Lower Devonian of the Barrandian area, Czech Republic (GAČR 17-102333S). Part of this contribution was also supported by the Research Program of the Institute of Geology AS CR, v.v.i. (RVO67985831). Work in this field by V.Ž. was supported by the EU-PLANTORIGINS-ITN project 238640. Special thanks to D. Edwards, School of Earth and Ocean Sciences, Cardiff University, UK, for valuable discussions.
The authors declare no competing interests.
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Libertín, M., Kvaček, J., Bek, J. et al. Sporophytes of polysporangiate land plants from the early Silurian period may have been photosynthetically autonomous. Nature Plants 4, 269–271 (2018). https://doi.org/10.1038/s41477-018-0140-y
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