The royal ferns (Order Osmundales, Class Polypodiopsida) comprise the extant family Osmundaceae, which contains 26 species in 6 genera (Encyclopedia of Life, https://eol.org/pages/3121225).
Leaving aside the phylogenetic network of the Osmundales generated by Bonfleur et al (2017), which is difficult to compare with the phylogenetic trees presented in this website, the only recent phylogenetic analysis is that by Wang et al (2014). This is the basis of the phylogenetic time tree shown below:
Leaving aside the phylogenetic network of the Osmundales generated by Bonfleur et al (2017), which is difficult to compare with the phylogenetic trees presented in this website, the only recent phylogenetic analysis is that by Wang et al (2014). This is the basis of the phylogenetic time tree shown below:
Figure 1. Time tree of the stem-Osmundales
The oldest known member of the osmundalean stem group is Grammatopteris rigollotii, described from the Autunian (latest Carboniferous to Early Permian) of France (Renault, 1891; Wang et al, 2014). No image of this species is available in the public domain, but another member of the genus, together with a few other members of the stem group for which public domain images are available, are illustrated below (for a larger view, click on image):
Names in red indicate that the fossil is younger than the oldest known crown-group fossil.
Figure 2. Images of stem-Osmundales
The above images are ordered from most basal to most crownward, but they are too few, and present too little information, to allow any trend to be discerned.
The oldest known member of the crown-Osmundales is Osmunda claytoniites, described from siltstones of Late Triassic age in Member C of the Lashly Formation in the Allan Hills, southern Victoria Land, Antarctica (Phipps et al, 1998; Table S2 in Grimm et al, 2015). No image is available in the public domain.
The osmundalean stem line includes a ghost lineage (shown as a blue bar in Figure 1), because the oldest known stem-group member of the Polypodiidae (the genus Senftenbergia, the oldest species of which are of Early Carboniferous age; Phillips and Galtier, 2011) is older than the stem-group Osmundales, which are of latest Carboniferous (Gzhelian) and younger age. Given that the two stem groups must have appeared at the same time, the osmundalean stem-group transition must also have begun in the Early Carboniferous (Serpukhovian). Comparing this age with that of the oldest member of the crown-Osmundales indicates that the stem-to-crown transition lasted between 86 and 130 million years, from the Early Carboniferous to Late Triassic time.
The oldest known member of the crown-Osmundales is Osmunda claytoniites, described from siltstones of Late Triassic age in Member C of the Lashly Formation in the Allan Hills, southern Victoria Land, Antarctica (Phipps et al, 1998; Table S2 in Grimm et al, 2015). No image is available in the public domain.
The osmundalean stem line includes a ghost lineage (shown as a blue bar in Figure 1), because the oldest known stem-group member of the Polypodiidae (the genus Senftenbergia, the oldest species of which are of Early Carboniferous age; Phillips and Galtier, 2011) is older than the stem-group Osmundales, which are of latest Carboniferous (Gzhelian) and younger age. Given that the two stem groups must have appeared at the same time, the osmundalean stem-group transition must also have begun in the Early Carboniferous (Serpukhovian). Comparing this age with that of the oldest member of the crown-Osmundales indicates that the stem-to-crown transition lasted between 86 and 130 million years, from the Early Carboniferous to Late Triassic time.
References
Bomfleur, B., Grimm, G. W., & McLoughlin, S. (2017). The fossil Osmundales (Royal Ferns)—a phylogenetic network analysis, revised taxonomy, and evolutionary classification of anatomically preserved trunks and rhizomes. PeerJ, 5, e3433.
Grimm, G. W., Kapli, P., Bomfleur, B., McLoughlin, S., & Renner, S. S. (2015). Using more than the oldest fossils: dating Osmundaceae with three Bayesian clock approaches. Systematic Biology, 64(3), 396-405.
Phipps, C. J., Taylor, T. N., Taylor, E. L., Cúneo, N. R., Boucher, L. D., & Yao, X. (1998). Osmunda (Osmundaceae) from the Triassic of Antarctica: an example of evolutionary stasis. American Journal of Botany, 85(6), 888-895.
Renault, B., 1891. Note sur la famille des Botryoptéridées. Bull. Soc. Hist. Nat. Autun 4, 349-373.
Wang, S. J., Hilton, J., He, X. Y., Seyfullah, L. J., & Shao, L. (2014). The anatomically preserved stem Zhongmingella gen. nov. from the Upper Permian of China: evaluating the early evolution and phylogeny of the Osmundales. Journal of Systematic Palaeontology, 12(1), 1-22.
Grimm, G. W., Kapli, P., Bomfleur, B., McLoughlin, S., & Renner, S. S. (2015). Using more than the oldest fossils: dating Osmundaceae with three Bayesian clock approaches. Systematic Biology, 64(3), 396-405.
Phipps, C. J., Taylor, T. N., Taylor, E. L., Cúneo, N. R., Boucher, L. D., & Yao, X. (1998). Osmunda (Osmundaceae) from the Triassic of Antarctica: an example of evolutionary stasis. American Journal of Botany, 85(6), 888-895.
Renault, B., 1891. Note sur la famille des Botryoptéridées. Bull. Soc. Hist. Nat. Autun 4, 349-373.
Wang, S. J., Hilton, J., He, X. Y., Seyfullah, L. J., & Shao, L. (2014). The anatomically preserved stem Zhongmingella gen. nov. from the Upper Permian of China: evaluating the early evolution and phylogeny of the Osmundales. Journal of Systematic Palaeontology, 12(1), 1-22.
Image credits – stem-Osmundales
- Header (Cinnamon fern - Osmunda cinnamomea – photographed in Ohio, USA on 23 May 2015): James St. John, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons
- Figure 2 (Grammatopteris baldaufi): Museum für Naturkunde Chemnitz; Licence: CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0/)
- Figure 2 (Guairea carnieri): Museum für Naturkunde Chemnitz; Licence: CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0/)
- Figure 2 (Osmundacaulis asiatica): From Open Access article Cheng, Y., Liu, F., Yang, X., & Sun, T. (2020). Two new species of Mesozoic tree ferns (Osmundaceae: Osmundacaulis) in Eurasia as evidence of long-term geographic isolation. Geoscience Frontiers, 11(5), 1875-1888.
- Figure 2 (Osmundacaulis sp., life restoration): Zeiram1990 on Dinopedia, Attribution-ShareAlike 3.0 Unported (CC BY-SA 3.0)
- Figure 2 (Millerocaulis zamunerae): Photo courtesy of Ana Sagasti, in Open Access article Mustoe, G. E. (2017). Wood petrifaction: A new view of permineralization and replacement. Geosciences, 7(4), 119.