Dryopteris × deweveri (J.T.Jansen) Jansen & Wacht., 1934

Common names

🇫🇷 Dryoptéride de Dewèvre, Dryoptéris de Dewèvre

Taxonomy

Kingdom: Plantae
Clade: Tracheophytes
Clade: Monilophytes
Class: Polypodiopsida
Subclass: Polypodiidae
Order: Polypodiales
Suborder: Polypodiineae
Family: Dryopteridaceae
Subfamily: Dryopteridoideae
Genus: Dryopteris
Species: Dryopteris × deweveri

Presence

Present.

Notes

Hybrid of D. carthusiana (Vill.) H.P.Fuchs, 1959 × D. dilatata (Hoffm.) A.Gray, 1848.

Possible confusion with D. expansa (C.Presl) Fraser-Jenk. & Jermy, 1977, which is absent below 800 m of altitude.

The first individual below was found in close proximity to its parent species in a mixed population. It shows light brown, concolorous scales on the petiole, pinnules that gradually narrow, and a long petiole, typical of D. carthusiana, and strongly expanded basal pinnae, typical of D. dilatata. Some of the petiole scales show a darker area at their point of insertion.

The second was found in a population of D. carthusiana. It shows light brown, concolorous scales on the petiole, typical of D. carthusiana, and strongly expanded basal pinnae, pinnules that narrow abruptly, and a short petiole, typical of D. dilatata. It is larger than the surrounding individuals of D. carthusiana, with fronds ≃ 100 cm long, which is not uncommon by itself for its parent species, but may indicate hybrid vigor.

Tetraploid (2n = 164).

Named after Alfred Dewèvre (1866-1897), a Belgian botanist.

While I am reasonably confident about the hybrid nature of these individuals based on macroscopic criteria, they have not been subjected to cytological examination or spore verification; thus, they remain potential hybrids.

Photographs

img/dryopteris-deweveri.webp — *Dryopteris × deweveri*

img/dryopteris-deweveri-2.webp — *Dryopteris × deweveri*

img/dryopteris-deweveri-3.webp — *Dryopteris × deweveri* - Pinnae

img/dryopteris-deweveri-4.webp — *Dryopteris × deweveri* - Pinnules

img/dryopteris-deweveri-5.webp — *Dryopteris × deweveri* - Pinnules

img/dryopteris-deweveri-6.webp — *Dryopteris × deweveri* - Basal pinna

img/dryopteris-deweveri-7.webp — *Dryopteris × deweveri* - First pinnules of basal pinna

img/dryopteris-deweveri-8.webp — *Dryopteris × deweveri* - Petiole showing light brown, concolorous scales

img/dryopteris-deweveri-16.webp — *Dryopteris × deweveri* - Petiole scale showing a darker area

img/dryopteris-deweveri-9.webp — *Dryopteris × deweveri*

img/dryopteris-deweveri-10.webp — *Dryopteris × deweveri*

img/dryopteris-deweveri-11.webp — *Dryopteris × deweveri* - Pinnae

img/dryopteris-deweveri-12.webp — *Dryopteris × deweveri* - Pinnules

img/dryopteris-deweveri-13.webp — *Dryopteris × deweveri* - Pinnules, abaxial side showing indusia and sori

img/dryopteris-deweveri-14.webp — *Dryopteris × deweveri* - Basal pinna

img/dryopteris-deweveri-15.webp — *Dryopteris × deweveri* - Petiole showing light brown, concolorous scales

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. 399). Biotope.