Taxonomy

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

Presence

Present.

Notes

Hybrid of P. cambricum L., 1753 × P. interjectum Shivas, 1961. Tetraploid (2n = 148).

This hybrid is common, although probably under-observed, and occurs in mixed populations of P. cambricum and P. interjectum. It can be recognized in the field by its large size and beige sori, and by an intermediate morphology between the two parent species, in particular fronds that gradually narrow (as in P. interjectum) with a long terminal segment and pointy pinnae (as in P. cambricum). Search for aborted spores and observation of the sporangia is necessary to confirm the identification.

Spores are grayish and variable in size, with some large viable diplospores. Sporangia have an annulus made of 6-8 cells, with 2-3 cells between the pedicel and the base of the annulus.

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

• Prelli, R., & Boudrie, M. (2024). Les fougères et plantes alliées d’Europe (2nd ed., p. 425). Biotope.

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