Floating Quillwort :: Isoetes wormaldii

Bad at Goodbyes :: Episode 076

On today’s show we learn about the Floating Quillwort, a critically endangered freshwater semi-aquatic plant native to South Africa, specifically to the Eastern Cape province, found roughly 25 miles from the coast. Its scientific name is Isoetes wormaldii and it was first described in 1906.

• (00:05) Intro
• (02:05) Species Information
• (19:13) Citations
• (20:57) Music
• (27:10) Pledge

Research for today’s show was compiled from:

• Azzella, M. M., Vecchia, A. D., Abeli, T., Alahuhta, J., Amoroso, V. B., Ballesteros, E., Bertrin, V., Brunton, D., Bobrov, A. A., Caldeira, C., Ceschin, S., Chemeris, E. V., Čtvrtlíková, M., de Winton, M., Gacia, E., Grishutkin, O. G., Hofstra, D., Ivanova, D., Ivanova, M. O., … Bolpagni, R. (2024). Global assessment of aquatic Isoëtes species ecology. Freshwater Biology, 69, 1420–1437. – https://doi.org/10.1111/fwb.14316
• Freund, F. D. (2022). The Genus Isoëtes L., evolution, diversification and population structure in a free-sporing heterosporous lycophyte. UC Berkeley. ProQuest ID: Freund_berkeley_0028E_21171. Merritt ID: ark:/13030/m5nx0dn2. – https://escholarship.org/uc/item/937695n1
• iNaturalist – https://www.inaturalist.org/observations?lat=-33.33523469222247&lng=26.571899142994628&quality_grade=research&radius=1.6281024631201406
• Larsén, E., Wikström, N., Khodabandeh, A. et al. Phylogeny of Merlin’s grass (Isoetaceae): revealing an “Amborella syndrome” and the importance of geographic distribution for understanding current and historical diversity. BMC Ecology and Evolution v 22, 32 (2022). – https://doi.org/10.1186/s12862-022-01988-w
• Larsén, E., Khodabandeh, A. & Rydin, C. (2025). Spore morphology and evolution in Isoëtes (Isoëtales). Botanical Journal of the Linnean Society, boaf078 – https://doi.org/10.1093/botlinnean/boaf078
• Mucina, Ladislav, Michael C. Rutherford, Johannes L. Nel, Jan H. J. Vlok, Doug I. W. Euston-Brown, Leslie W. Powrie, Anthony P. Dold, and Robert A. Ward. 2006. "Azonal Vegetation." In The Vegetation of South Africa, Lesotho and Swaziland, edited by Ladislav Mucina and Michael C. Rutherford, 614–648. Strelitzia 19. Pretoria: South African National Biodiversity Institute. – https://www.sanbi.org/wp-content/uploads/2024/05/2006_Strelitzia19.pdf
• Sim, T. R. 1915. The Ferns of South Africa, Containing Descriptions and Figures of the Ferns and Fern Allies of South Africa. Cambridge [Eng.]: University Press. – https://www.biodiversitylibrary.org/page/51313623
• Victor, J. E., and A. P. Dold. 2003. "Threatened Plants of the Albany Centre of Floristic Endemism, South Africa." South African Journal of Science 99 (9/10): 437–446. – https://hdl.handle.net/10520/EJC97693
• Victor, J. E., & Dold, A. P. (2007). "Isoetes wormaldii Sim". National Assessment: Red List of South African Plants version 2024.1. South African National Biodiversity Institute. – http://redlist.sanbi.org/species.php?species=2184-15
• Victor, J.E. & Dold, A.P. 2010. Isoetes wormaldii. The IUCN Red List of Threatened Species 2010: e.T185429A8409995. – https://dx.doi.org/10.2305/IUCN.UK.2010-3.RLTS.T185429A8409995.en
• Wickell, D., Kuo, LY., Yang, HP. et al. Underwater CAM photosynthesis elucidated by Isoetes genome. Nature Communications v.12, 6348 (2021). – https://doi.org/10.1038/s41467-021-26644-7
• Wood D, Besnard G, Beerling DJ, Osborne CP, Christin PA (2020) Phylogenomics indicates the “living fossil” Isoetes diversified in the Cenozoic. PLOS ONE 15(6): e0227525. – https://doi.org/10.1371/journal.pone.0227525
• Wikipedia – https://en.wikipedia.org/wiki/Isoetes

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A note on accuracy: I strive for it! These episodes are well-researched and built from scholarly sources, hoping to provide an informed and accurate portrait of these species. That said, I’m a musician! I am not an academic and have limited scientific background. I may get things wrong! If you are using this podcast for scholarship of any kind, please see the cited sources and double-check all information.