All posts by Roger Golding

Perplexed by pseudocomplexa

Perplexed by pseudocomplexa

I think I’m finally started to get to grips with Dryopteris cambrensis ssp. pseudocomplexa (also known as Dryopteris affinis morphotype arranensis). This has been annoying me for a long time. It seems to be very restricted in distribution and is perhaps the least well-known member of the affinis group in Britain. There are records from Arran, Islay and Skye – I don’t know of any other definite ones. It’s also been found in southern Ireland, Norway, France and possibly Austria. Most of the British records have been made by Tony Church. The type was described by Christopher Fraser-Jenkins from specimens collected on Skye in 1984 and 1986: “woods in from gate, just south of Dunvegan Castle car-park”. Several years ago I went there and spent some considerable time fossicking around in the woods south of the car park – now overgrown with rhododendrons and quite difficult to access. I didn’t find anything I could recognise as this fern. I also paid the entry fee and wandered around the castle grounds, again with no success.

The late Ken Trewren pointed to a plant in Kirkbean Glen as being this subspecies. I was with him at the time but couldn’t look at it in detail as we were with a group hurrying on to look at other things, so I just made a note of the spot and determined to come back some time. 2 years ago I visited there again, and could find no sign of anything that matched the description. Mystifying and frustrating. I subsequently learned Ken had later decided it wasn’t pseudocomplexa after all, which explains why I couldn’t find it…

Armed with various descriptions, including those written by Fraser-Jenkins, Ken Trewren and Anthony Pigott, including Ken’s guide Some Taxa within the Dryopteris affinis complex, I headed back to Dunvegan Castle. Another unsuccessful foray into the woods south of the car park, which were even more overgrown than I remembered. In the bits I could get into there were many plants of Dryopteris borreri and filix-mas, D. dilatata, Blechnum spicant, Athyrium filix-femina; no sign of pseudocomplexa. Again I paid the entry fee for the castle grounds (note to self: someday must have a look at the actual castle). Raining hard by this time and I was starting to feel a bit grumpy, dodging tourists while trying to examine every affinis-type fern I could find. Then in a ditch near the walled garden I finally spotted something different – at last a fern that matched the description! Further down the same ditch in the direction of the harbour were two more.

Buoyed up by this success, I decided to explore some more of the woodland outside the castle grounds. This time I followed the path which runs east through the woods. As far as I can tell, since the original collections were made, the car park has been extended, so the gate no longer accesses the woods to the south. Eventually I found two plants some distance apart from each other – big, old clumps with multiple crowns. Not too far away Ostrich Fern (Matteuccia struthiopteris) has escaped from the castle grounds and appears to be having a good time in the boggy wood.

D. cambrensis ssp. pseudocomplexa in the woods near Dunvegan Castle
D. cambrensis ssp. pseudocomplexa in the woods near Dunvegan Castle

Of all the affinis group pseudocomplexa seems to me the least obviously ‘affinis-like’. The name implies similarity to hybrids of D. affinis with D. filix-mas (D. x complexa sensu lato), but although it has some similarities to D. filix-mas I find similarity to the hybrids harder to see. It also lacks much obvious similarity to D. cambrensis ssp. cambrensis.

A single frond
A single frond
Close-up of frond
Close-up of frond

It has a rather thin delicate stipe and the fronds have a fairly soft texture with what I would call a medium level of glossiness (in paint terms, a bit more than satin but not the full gloss of D. affinis); the dark spot at the junction of the stipe and rachis is not particularly strong; and the pinnules appear from a distance mostly almost unlobed and untoothed. Closer inspection of the plants I looked at showed that some of the pinnules – particularly those nearer the rachis – have rudimentary lobes and some have a few rather indistinct teeth at the mostly rounded tips. The pair of pinnules at the base of the pinnae (especially the lower or downward-pointing one) are the most lobed, the lobes having curved rather than straight edges, and are longer and more developed than the others. The pinnae and pinnules are quite well-spaced, not overlapping at all.

Sori nearing maturity
Sori nearing maturity
Base of pinna, lower part of frond
Base of pinna, lower part of frond
Base of pinna, middle of frond
Base of pinna, middle of frond

The stipe scales are a pale tan colour with only slightly darker bases – noticeably pale compared to most of the affinis group.

Scales on stipe
Scales on stipe

With thanks to Tony Church and Alison Evans for the help in confirming the identity of these plants.