Taxonomy

• Kingdom: Plantae
• Clade: Tracheophytes
• Clade: Monilophytes
• Class: Polypodiopsida
• Subclass: Polypodiidae
• Order: Polypodiales
• Suborder: Polypodiineae
• Family: Polypodiaceae
• Subfamily: Polypodioideae
• Genus: Polypodium
• Species: Polypodium interjectum

Presence

Present.

Conservation status

• Red List (Metropolitan France): LC Least Concern
• Red List (Europe): LC Least Concern

Notes

Possible confusion with P. cambricum L., 1753, which has wider fronds (length/width ratio < 2) and paraphyses in the sori, while P. interjectum has narrower fronds (length/width ratio > 2 and ≤ 3) and lacks paraphyses.

Possible confusion with P. vulgare L., 1753, which has narrower fronds (length/width ratio ≥ 3) and sporangia with a dark brown annulus made of 11-14 cells, while P. interjectum has wider fronds (length/width ratio > 2 and ≤ 3) and sporangia with a light brown annulus made of 7-9 cells.

Individuals of P. interjectum with a higher count of indurated cells are not uncommon. In that case, the number of basal cells (2-3 in P. interjectum, 0-1 in P. vulgare) should be taken into consideration (Ivanova, 2006).

Allohexaploid (2n = 222).

Hybridizes with:

• P. cambricum L., 1753 to produce P. × shivasiae Rothm., 1962, P;
• P. vulgare L., 1753 to produce P. × mantoniae Rothm., 1962, P.

Photographs

Sources

• Badré, F., & Deschatres, R. (1979). Les Ptéridophytes de la France : liste commentée des espèces (taxinomie, cytologie, écologie et répartition générale). Candollea, 34(2), 379-457. https://doi.org/10.5169/seals-880127

• Christenhusz, M., Bento Elias, R., Dyer, R., Ivanenko, Y., Rouhan, G., Rumsey, F., & Väre, H. (2017). Polypodium interjectum (Europe assessment). The IUCN Red List of Threatened Species, 2017. https://www.iucnredlist.org/species/83650727/85447694

• Ivanova, D. (2006). Polypodium interjectum and P. ×mantoniae (Polypodiaceae: Pteridophyta), new to the Bulgarian flora. Phytologia Balcanica, 12 (2), 191-202.

• Prelli, R., & Boudrie, M. (2024). Les fougères et plantes alliées d’Europe (2nd ed., p. 420). Biotope.

• Tison, J.M., & de Foucault, B. (2014). Flora Gallica : Flore de France (p. 23). Biotope.