# Parablechnum wattsii

**Parablechnum wattsii** (Tindale) Gasper & Salino, commonly known as the hard water-fern, is a species of fern in the family [Blechnaceae](https://www.edgepedia.org/blechnaceae) native to eastern and southeastern Australia. It was first described as *Blechnum wattsii* by Tindale in 1963 and transferred to the genus *Parablechnum* in 2016.<sup>[1](https://powo.science.kew.org/taxon/urn%3Alsid%3Aipni.org%3Anames%3A17430860-1)</sup><sup> • </sup><sup>[2](https://www.ipni.org/n/17430860-1)</sup><sup> • </sup><sup>[3](https://www.inaturalist.org/taxa/48433-Blechnum)</sup>

| Key fact | Detail |
|---|---|
| Scientific name | *Parablechnum wattsii* (Tindale) Gasper & Salino; basionym *Blechnum wattsii* Tindale<sup>[1](https://powo.science.kew.org/taxon/urn%3Alsid%3Aipni.org%3Anames%3A17430860-1)</sup> |
| Original publication | Contr. New South Wales Natl. Herb. 3: 247 (1963); type distribution Australia<sup>[2](https://www.ipni.org/n/17430860-1)</sup> |
| New combination | Phytotaxa 275(3): 217 (2016), in the recircumscription of Blechnaceae by de Gasper, Dittrich, Smith, and Salino<sup>[2](https://www.ipni.org/n/17430860-1)</sup><sup> • </sup><sup>[4](https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=393587)</sup> |
| Family and subfamily | Blechnaceae, subfamily Blechnoideae<sup>[4](https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=393587)</sup> |
| Native range | Eastern and southeastern Australia: New South Wales, Queensland, South Australia, Tasmania, and Victoria; grows primarily in the subtropical biome<sup>[1](https://powo.science.kew.org/taxon/urn%3Alsid%3Aipni.org%3Anames%3A17430860-1)</sup> |
| Common name | Hard Water-Fern<sup>[3](https://www.inaturalist.org/taxa/48433-Blechnum)</sup> |

## Taxonomy and nomenclature

The species was described by Tindale in 1963 in *Contributions from the New South Wales National Herbarium*, with the type from Australia.<sup>[2](https://www.ipni.org/n/17430860-1)</sup> In 2016, de Gasper and colleagues published a revised classification of the Blechnaceae that split the broadly defined genus *Blechnum* into several genera, including *Parablechnum*, and made the combination *Parablechnum wattsii*.<sup>[2](https://www.ipni.org/n/17430860-1)</sup><sup> • </sup><sup>[4](https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=393587)</sup> The genus *Parablechnum* C.Presl is the most diverse genus in the family, with about 65 species whose range has two major centers of diversity, one in Meso and South America and a second centered in Eastern Australasia.<sup>[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC9836480/)</sup>

Databases differ in which name they accept. Plants of the World Online treats *Blechnum wattsii* as the accepted name and lists *Parablechnum wattsii* as its homotypic synonym, following authorities such as the 2022 census of Tasmanian vascular plants by de Salas and Baker; the World Ferns checklist instead cites the species as *Parablechnum wattsii*.<sup>[1](https://powo.science.kew.org/taxon/urn%3Alsid%3Aipni.org%3Anames%3A17430860-1)</sup> The NCBI Taxonomy Browser records *Parablechnum wattsii* as the current name with *Blechnum wattsii* as basionym.<sup>[4](https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=393587)</sup>

## Distribution and records

The native range covers the Australian states of [New South Wales](https://www.edgepedia.org/new-south-wales), Queensland, South Australia, Tasmania, and Victoria, and the species is associated primarily with the subtropical biome.<sup>[1](https://powo.science.kew.org/taxon/urn%3Alsid%3Aipni.org%3Anames%3A17430860-1)</sup> [Herbarium](https://www.edgepedia.org/herbarium) material documents the species beyond mainland Australia: the [National Museum of Natural History](https://www.edgepedia.org/national-museum-of-natural-history) in Paris holds a specimen, P01462494, collected on Norfolk Island, which was earlier determined as *Blechnum capense* (L.) Schltdl. and redetermined as *Parablechnum wattsii* in 2021.<sup>[6](https://science.mnhn.fr/institution/mnhn/collection/p/item/p01462494?listIndex=13)</sup> The species also appears in phylogenetic sampling of the genus alongside other Australasian members such as *P. novae-zelandiae*, *P. minus*, and *P. ambiguum*.<sup>[7](https://academic.oup.com/evolut/advance-article-pdf/doi/10.1093/evolut/qpae159/60338441/qpae159.pdf)</sup>

## References

1. [Blechnum wattsii Tindale, Plants of the World Online, Kew Science](https://powo.science.kew.org/taxon/urn%3Alsid%3Aipni.org%3Anames%3A17430860-1)
2. [Blechnum wattsii, International Plant Names Index](https://www.ipni.org/n/17430860-1)
3. [Hard ferns (Genus Blechnum), iNaturalist](https://www.inaturalist.org/taxa/48433-Blechnum)
4. [Taxonomy Browser: Parablechnum wattsii, NCBI](https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=393587)
5. [Morphological and molecular evidence reject conspecificity of Malagasy and Mascarene Parablechnum (Blechnaceae), PMC](https://pmc.ncbi.nlm.nih.gov/articles/PMC9836480/)
6. [Specimen P01462494, Muséum national d'Histoire naturelle](https://science.mnhn.fr/institution/mnhn/collection/p/item/p01462494?listIndex=13)
7. [Phylogenetic tree, Evolution (2024)](https://academic.oup.com/evolut/advance-article-pdf/doi/10.1093/evolut/qpae159/60338441/qpae159.pdf)

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*Topic: Encyclopedia › Life and health › Plants and algae › Ferns and lycophytes › Polypod fern families › Blechnoid ferns and former Blechnum synonyms › Parablechnum*

*Initially written Sep 17, 2026 · Reviewed: Oct 21, 2026 · Edited: Oct 15, 2026; Oct 21, 2026 · Last review: Oct 21, 2026*

*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*

License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license