After a long time a fern is topic of this blog again and it's even one of the well known and most common ferns at all. It's Dryopteris filxi-mas (L.) Schott (Common Male Fern” in Englisch and “Echter Wurmfarn” in German), a member of the Dryopteridaceae.
D. filix.mas - habitus of a frond
It's a medium sized fern with dark green and single pinnate fronds, which are narrowing toward the base. The individual leaflets are rounded and a little bit serrated. The sori (groups of sporangia) are sitting in two rows at the underside of fertile fronds, which are not shaped differently toward sterile fonds. They are kindney- or dot-shaped. Each Sorus is alos covered by a small, grey veil, which is called “Indusium”
D. filix-mas - closer look at the leaflets
D. filix-mas - Sori with grey indusia
Sometimes, D. filix-mas is confused with Athyrium filix-femina (L.) Roth. (Woodsiaceae) or Dryopteris affinis (Lowe) Fraser-Jenk. by beginners, because these three species looks very similar to each other. However, the fronds of A. filix-femina are much finer feathered and the sori are comma-shaped. D. affinis on the other side has chaff scales all of its frond and a small violet ring at the base of each leaflet.
D. filix-mas - this a very young frond,
which hasn't outspred yet. So in this state
the fern looks like the scroll of a violin
D. filix-mas - Old frond
D. filix-mas - Sori at an old frond;
the indusia has dissarpeared
D. filix-mas is common throughout the whole Northern Hemisphere, e g. Europe, North America or North and Central Asia. It likes fresh forests, bushes or tall herb lands and clearings.