Came to settle in much of Europe and North Africa, coinciding with a period of subtropical climate, warm and moist laurel forests which had its greatest expansion. With the last ice was retreating towards the south and east, fleeing the cold, being held since then in the four archipelagos of Macaronesia, several localities in Portugal where persistent pockets of laurel forest, such as Sierra de Mafra and Sierra de Sintra-Cascais, and some cool, damp locations in northern Africa (Morocco, Algeria and Tunisia).
The symmetry of sori seems designed by a mathematician. The one half is the mirror image of the other half. Have a linear structure and are distributed along the veins of the frond. The photo is immature, yet covered by the indusium which is membranaceous, rigid, narrow and wide.
Underside of frond with sori other mature, with the indusium up for the sporangia to disperse the spores. In the photograph you can see a dark dust around the sori which are the spores. You can also see the long black petiole of fronds. (Double click on the photo to enlarge.)