Tuesday, September 3, 2013

Marginal Wood Fern (Dryopteris marginalis)

Also known as the Marginal Shield Fern, and having been re-classified several times by other binomial epithets such as Thelypteris marginalis, Aspidium marginale and Polypodium marginale.

Due to a paucity of photos this striking fern was glossed over in A Duo of Dryopteris. In the month since those photos were taken my fern spotting skills have improved and I've encountered several other Marginal Wood Ferns closer to home in our local woodlands. This is the overall aspect or growth form of the fern, note how the fronds grow in a more or less circular pattern from the same place.

A look at the undersides of the pinnae – note how the sori are situated along the margins of the leaflets (a.k.a. pinnae).

The bottom view of the blade from another specimen.

Some closeup shots of the blade's underside, these are by far the nicest examples of how the sori arranged along the margins of the pinnae that I've encountered to date – a textbook case.

A chaffy stipe is by no means unique to the Marginal Wood Fern, but it is another identifying characteristic.