Tag: Dryopteris

Year of Ferns: Woodland in Winter

Motivated by last year’s fern forays and spurred on by my new membership of the British Pteridological Society, I have decided to try something different this year: a personal challenge to see as many of Britain’s fern species as possible in a single year. The idea being that, by seeking out our ferns, I’ll learn more about them, their habitats, and the subtleties involved in identifying them. This blog will be part #2.

Woodland Ferns – 17th January

By January, our woodlands are not looking especially vibrant. Cold, wet, and muddy, they are far removed from their spring splendour, and by this point in the year, most of our ferns are looking rather jaded too.

With this in mind, yesterday saw us meandering through Jesmond Dene, keen to see what could still be picked out in the depths of January. As expected, most of the ferns looked rather gnarled by the frosts, but in sheltered spots our two most familiar woodland species could still be found.

Broad Buckler-fern Dryopteris dilatata, with its broad, wedge-shaped fronds and dark-centred scales, was easily located, as was Male-fern Dryopteris filix-mas with its tapering fronds and toothed pinnules. These are perhaps our most abundant native ferns both will look far better come spring.

Broad Buckler-fern Dryopteris dilatata, with its broad, wedge-shaped fronds
Male-fern Dryopteris filix-mas with its tapering fronds and toothed pinnules.
Toothed, tapering pinnules of Dryopteris filix-mas

Continuing our walk, it was also pleasing to see several healthy clumps of Hart’s-tongue Asplenium scolopendrium looking altogether more robust and vibrant than the straggly individuals spotted on walls during our previous outing.

A healthy example of Hart’s-tongue Asplenium scolopendrium clinging to a bank.

Another group of evergreen woodland ferns still visible at this time of year are the Polystichum species – the Shield-ferns. Our two native species are both fairly common in shady woodland settings and are easily recognised by their distinctly “mitten-shaped” pinnules. They can be told apart by a combination of features, most notably the overall shape of the frond (gradually tapering versus ending abruptly), whether the pinnules are stalked, and the angle of the lowest pair of pinnules (obtuse vs acute).

In images one and three below, we have Soft Shield-fern Polystichum setiferum: soft to the touch, with a truncate base and pinnules set at an obtuse angle. The third image shows an escaped cultivated form, noticeably more frilly in appearance – a reminder of the interesting things we humans have done to ferns. Note in both examples, the pinnules are stalked. This is also a useful factor in separating these species, as set out in the helpful crib here. A good blog on the two native species can also be found here.

Pinnules of Polystichum setiferum, soft to the touch
A cultivated form of Polystichum setiferum with very frilly foliage.
I did toy with the idea of this plant being the hybrid of Soft and Hard Shield-ferns but alas, I think it just P. setiferum

Close to the first Shield-fern, we also noticed a rather lovely Polypody Polypodium sp clinging to a bridge. I have learned through bitter experience how difficult it is to separate these species on visual characters alone, so having collected a small sample, I’ll be checking the spores later. Stay tuned for another post on those.

A nice Polypodium species clinging to the stonework of a bridge.

Last but not least on our morning walk through Jesmond Dene, we stopped to check in on a more unusual fern, first noted last year while recording for my upcoming Urban Flora of Newcastle. At first glance, you might notice that it looks rather similar to the Soft Shield-fern shown previously – and that’s because it is, albeit a little more exotic in nature.

This plant is, in fact, Japanese Lace Fern Polystichum polyblepharon, a widely cultivated garden species that appears to have found its way into the Dene of its own accord. This young plant is growing on a steep, muddy bank where deliberate planting seems highly unlikely, and so can presumably be counted towards this year’s fern fest. As mentioned previously, non-native ferns will count provided they appear to be self-sown.

Japanese Lace Fern Polystichum polyblepharon, an oddity of Jesmond Dene

Right Back at It – 23rd January

After work on Friday, I opted for a rather rainy afternoon walk back into the Dene, this time venturing a little further to see what I could find. It was pleasing to come across another Polypodium, this time growing on a tree, though it lacked the spores needed for identification.

Polypodium species growing on a moss-covered tree in Jesmond Dene

Further along the Ouse Burn, the challenge’s next “new” fern became apparent: Hard Shield-fern Polystichum aculeatum, with its sessile, acute-angled pinnules and tapering fronds. This is one of the scarcer of the ‘common’ ferns in my part of Newcastle, so it’s always nice to see.

Young Hard Shield-fern Polystichum aculeatum clinging to a slope
Pinnule shape of Hard Shield-fern Polystichum aculeatum
A larger specimen of Hard Shield-fern Polystichum aculeatum

In the same area that held the shield-fern, it was also pleasing to find two slightly straggly examples of the once-pinnate Hard Fern Blechnum spicant. This species needs little introduction.

Hard Fern Blechnum spicant in Jesmond Dene

Slightly more perplexing are the Scaly Male-ferns Dryopteris affinis agg. These were always going to be the most difficult group to contend with during this year’s fern challenge, and no matter how much time I spend looking at them, they still manage to confuse me. Inevitably, I find myself examining a great many specimens before eventually settling on one that matches the descriptions in the various resources stuffed into my rucksack – most of which contradict one another to some degree.

The two common species involved are Borrer’s Scaly Male-fern Dryopteris borreri and Western Scaly Male-fern Dryopteris affinis subsp. affinis.

A selection of Scaly Male-ferns in Jesmond Dene

D. affinis subsp. affinis is soundly evergreen, so as a first step, I looked for a fern that still appeared reasonably fresh for mid-January. Having succeeded, it was time for a closer inspection. As far as I recall, affinis is the only one of the common Scaly Male-ferns to have an adnate lowest basiscopic pinnule (that is, lacking a stalk). It also has rather lucid veins that extend all the way to the pinnule margin, and lowest pinnules on each pinna that are roughly the same size as their neighbours, unlobed and rounded at the tip.

The fern shown below seemed to fit this description, at least in most respects. With a degree of trepidation, I’m therefore calling it Dryopteris affinis subsp. affinis.

Lowest pinnules of Western Scaly Male-fern Dryopteris affinis subsp. affinis
Lowest basiscopic pinnule of D. affinis

In contrast to affinis, D. borreri has stalked lowest basiscopic pinnules and lowest pinnules that are slightly longer than their neighbours. These are also toothed at the corners (in the typical form, at least) and show slightly more diffuse venation that stops short of the pinnule margins. All quite straightforward in theory.

Taking a frond from one slightly more convincing example and examining it more closely, most of these characteristics are present, particularly in the shape of the pinnules. However, I don’t yet feel that I’ve fully got to grips with the differences in venation. The plant I tentatively labelled as affinis does not appear identical to examples I have seen online. This borreri, however, shows the pale blotching often mentioned in the literature, which is reassuring.

Lowest pinnules of Dryopteris borreri
Pale blotching between veins that (largely) stop short of the pinnule margin

We’ll certainly have to revisit these before attempting any of the rarer ferns within the complex, but hey, practice makes perfect (or so I am told).

Running Total

Seeing as I rarely carry a notebook, we’ll log our running total for the year here…

#1 Wall-rueAsplenium ruta-muraria16 January, Newcastle
#2 Maidenhair SpleenwortAsplenium trichomanes subsp. quadrivalens16 January, Newcastle
#3 Hart’s-tongueAsplenium scolopendrium16 January, Newcastle
#4 Black SpleenwortAsplenium adiantum-nigrum16 January, Newcastle
#5 Broad Buckler-fernDryopteris dilatata17 January, Newcastle
#6 Male-fernDryopteris filix-mas17 January, Newcastle
#7 Soft Shield-fernPolystichum setiferum17 January, Newcastle
#8 Japanese Lace FernPolystichum polyblepharum17 January, Newcastle
#9 Hard Shield-fernPolystichum aculeatum23 January, Newcastle
#10 Hard FernBlechnum spicant23 January, Newcastle
#11 Western Scaly Male-fernDryopteris affinis subsp. affinis23 January, Newcastle
#12 Borrer’s Scaly Male-fernDryopteris borreri23 January, Newcastle

On the hunt for Dryopteris lacunosa

Last week, I visited an abandoned quarry in Upper Teesdale and found myself puzzling over an unusual-looking fern. It seemed to resemble both Borrer’s Male-fern Dryopteris borreri and the Common Male-fern Dryopteris filix-mas, but something didn’t feel quite right – at least to my novice eyes.

The main point of confusion was the distinctive ‘dark spot’ at the base of the costa which typically helps identify the scaly male-ferns. In this specimen, the spot was unusually extensive and, on the underside of the pinna, extended some way up the costa. From my hazy recollection, in D. borreri, this spot is usually fairly faint and confined to the point where the pinna meets the rachis.

Beyond that, I was stumped. Aside from snapping the photos below, I decided to leave it there. However, having revisited a few Facebook posts from local botanist, John Durkin, mentioning that same feature in another species, Alpine Male-fern Dryopteris lacunosa, I am beginning to wonder…

Unknown Dryopteris from Upper Teesdale

After a deep dive on the internet, I found relatively little information about Dryopteris lacunosa. It appears to be a fairly recent split from the Dryopteris affinis aggregate and has only recently started to be recorded in parts of the UK. From what I can gather, most records are concentrated in Cumbria, western Scotland, Wales, and southern Ireland. Pleasingly, however, the species has now been recorded at a few select sites in North East England – thanks to the efforts of recorders far more knowledgeable than I.

One of these sites, Blaydon Burn, lies just a short distance from home so with a day off work, I thought I’d try to seek it out for myself.

Dryopteris lacunosa at Blaydon

The most helpful information I’ve found on Dryopteris lacunosa comes from an excellent page by Roger Golding, which includes images highlighting the key features to look out for – most notably, that extended dark blotch on the costa. A very informative online talk by Alison Evans offers further insight, mentioning additional traits such as the distinctive double teeth, funnel-shaped gaps between the teeth, and the long stalks on the pinnae. A third mention, on a blog by the Kirkcudbrightshire Botany Group, echoed many of these points. All of it made for very useful reading on the bus to Blaydon!

Blaydon Burn Nature Reserve was entirely new to me, but with its steep, well-vegetated banks lining the burn, it immediately looked promising for ferns. And indeed, it delivered with plenty of Male-fern, Borrer’s Male-fern, and Broad Buckler-fern Dryopteris dilatata noted, along with Hard-fern Blechnum spicant, Lady-fern Athyrium filix-femina, and Hard Shield-fern Polystichum aculeatum. All species one can expect to encounter in Tyneside’s humid denes.

The first interesting fern (pictured below) came about 15-minutes into the walk…

Possible Dryopteris lacunosa showing extensive dark spot
Upperside of the pinnules showing teeth
The whole plant

In the individual pictured above, the dark mark at the junction of the costa and rachis was extremely pronounced extending, in some cases, a good inch up the stem. In this neck of the woods, that would suggest either D. borreri or D. lacunosa (it certainly wasn’t D. affinis). If you look closely at the zoomed-in image below, you can also make out double teeth on the auricles (the ‘ear’ or lobe at the base of the pinnule). These were distinctive in some cases but rather variable, and certainly not present on all of the lowest pinnules I examined.

The gaps between the teeth were even less clear-cut, and I must admit this isn’t an area I’m particularly familiar with. That said, in many instances, they could reasonably be described as funnel-shaped, though I do rather like the ‘fjord-shaped’ description mentioned in the video linked above.

A closer look at those teeth

After pottering further into the woods, I came across two more promising individuals on a slope among patches of both D. filix-mas and D. borreri. In these specimens, the dark marking was even more extensive and far more convincing. The pinnae stalks also appeared longer, and at least some double teeth were clearly visible. I still can’t quite wrap my head around the reference to ‘islands’ in this resource, but otherwise, the features seemed to line up well.

Possible Dryopteris lacunosa #2
and #3
A more impressive dark spot
Funnel-shaped teeth?
The most extensive of the dark markings

The fourth and final candidate I found was a small, immature specimen perched above an eroded area further up the bank. Most of its fronds had yet to develop the characteristic dark mark, but on one mature frond, the blotch was incredibly extensive – more so than I’ve seen on any fern before. This feature alone was more convincing than the presence of double teeth, though the auricles on the more mature frond were clearly toothed as well.

Possible Dryopteris lacunosa #4
Dark marking extending up costa
The whole plant

Having spent a good few hours now examining collected fronds and poring over photos from the trip, I feel reasonably confident that I’ve found something different from the ferns I usually encounter. After comparing my specimens to images associated with accepted records of Dryopteris lacunosa in the local area, I’m cautiously optimistic that this may, in fact, be it. That said, I wouldn’t be at all surprised if I’m mistaken – ferns are a notoriously tricky group, and despite the time I’ve been dedicating to learning them, they continue to frustrate me no end. If, by chance, a proper pteridologist stumbles across this post, please do feel free to correct me!

As for my original Teesdale fern – the jury is still out. The dark spot is certainly promising, but the absence of double teeth (or lobes, for that matter, as seen in Roger Golding’s images) is a bit disconcerting. I won’t be submitting a record for that one unless someone with more expertise can weigh in and help clarify things.