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 #3.
Asplenium x clermoniae – 26th January
On Sunday, a trip north into rural Northumberland provided a welcome opportunity to check in on one of the rarest and most intriguing ferns in North East England: Lady Clermont’s Spleenwort Asplenium × clermontiae – a hybrid I hadn’t seen since 2023, when I published a short blog about it here.
To cut a long story short, this is an exceedingly rare hybrid between Wall-rue Asplenium ruta-muraria and Maidenhair Spleenwort Asplenium trichomanes subsp. quadrivalens. On paper, it ought to be more widespread, given the abundance of its parent species, but this is very much not the case. In fact, it is currently known from just three individual plants across the entirety of the British Isles. The Northumberland plant has been known since the early 2000s and has been visited by many pteridologists over the years.
It is a rather unruly-looking fern, showing characteristics of both parents, and so far as this year’s pteridological challenge goes, an excellent one to notch up early on.
Lady Clermont’s Spleenwort Asplenium x clermontiae
A short distance away, another unassuming wall played host to a second rare little spleenwort, though not quite so rare as the species mentioned above. Rustyback Asplenium ceterach is common in many parts of the UK but decidedly scarce in the North East and, despite an abundance of seemingly suitable habitat, remains confined to a small number of quarries and walls across the region. I do wonder whether climate plays a part. In North Northumberland, it is a Rare Plant Register species, meaning it should be reported whenever encountered.
A lover of limestone rocks and lime-rich mortar, this species is easy to identify thanks to its thick, leathery, almost once-pinnate fronds and the dense covering of rust-coloured scales on the underside. The images below show one of two plants observed during a brief pit stop at a well-known site.
Another species down…
Rustyback Asplenium ceterach
Running Total
Seeing as I rarely carry a notebook, we’ll log our running total for the year here…
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-fernDryopteris dilatata, with its broad, wedge-shaped fronds and dark-centred scales, was easily located, as was Male-fernDryopteris 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 frondsMale-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-fernPolystichum 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 touchA 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 FernPolystichum 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-fernPolystichum 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 slopePinnule shape of Hard Shield-fern Polystichum aculeatumA 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 FernBlechnum 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. affinisLowest 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 borreriPale 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…
Motivated by last year’s successful 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.
The premise is simple: any fern growing in a wild situation counts, as do subspecies, hybrids, and species accepted by the major authorities. I will do my utmost to document each new find here, beginning with easily accessible species and, hopefully, progressing to trickier ones further down the line.
Urban Ferns – 16th January
It seemed reasonable to kick-start this year’s pteridological challenge with something low-key and ordinary. Thus, a search for wall ferns was on the cards.
On a typical street in Newcastle, there are four or five ferns that commonly occur on walls, most of which belong to the genus Asplenium. What I find especially interesting about Asplenium is that it is a genus of polar opposites. Perhaps half a dozen species are so widespread as to seem almost mundane, while others rank among our most elusive ferns, known only from a few carefully guarded sites. When it comes to the former group, the good news is that you don’t need to travel far to find them.
Skulking along some Heaton terraces, it wasn’t long before we came across our first species: Wall-rueAsplenium ruta-muraria, growing snugly in the mortar. Around fifteen plants clung to the wall, many stunted but unmistakable on account of their small, fleshy, club-shaped fronds. It is an easy species to recognise, and one of the commonest of our ferns.
A healthy clump of Wall-rue Asplenium ruta-murariaA pitiful example of Wall-rue Asplenium ruta-muraria growing alongside Hart’s-tongue
Mixed in among them were examples of Maidenhair SpleenwortAsplenium trichomanes, its fronds borne on dark, wiry stems and clustered in tight tufts within the mortar. While easy to recognise at first glance, there is more to this little fern than meets the eye. What we collectively know as Maidenhair Spleenwort is, in fact, an aggregate of three subspecies, each occupying its own ecological niche. Two of these are rather rare; the third is incredibly common.
Distinguishing between the subspecies requires attention to detail: the shape of the pinnules, the point of insertion of the stalk, the colour of the rachis, and the angle of growth against the substrate. Truth be told, it is a fiddly, detailed, and at times frustrating affair – though it is possible to cheat. The simplest shortcut is habitat. The commonest subspecies, quadrivalens, is a calcicole: a lover of lime. In the wild, it grows on calcareous rocks, but it is equally at home in the lime-rich mortar of brick walls. The second, trichomanes, is a much rarer plant of acidic rocks, typically confined to upland areas and occasionally encountered on dry-stone walls. The third, pachyrachis, is so scarce that it barely warrants consideration here, though for completeness it favours damp limestone and is restricted to just a few corners of the British Isles. By process of elimination, our plant could only be subsp.quadrivalens – a conclusion quickly confirmed by the insertion of the stalk at the corner of each pinnule.
A sorry example of Maidenhair Spleenwort Asplenium trichomanes subsp. quadrivalensA healthier colony of Maidenhair Spleenwort Asplenium trichomanes subsp. quadrivalens on a sheltered wall
Where these two species occur, a third often appears as well, though it rarely looks healthy when growing on walls. Hart’s-tongueAsplenium scolopendrium may tolerate such habitats, but it much prefers the shade and humidity of woodland, where it typically grows on mildly alkaline soils. Perhaps our most recognisable native fern, with its glossy, lime-green, tongue-like fronds, it presents few challenges. It is also a particularly useful Asplenium for demonstration purposes. The specific epithet scolopendrium is derived from the Greek skolopendra, meaning centipede – an allusion to the arrangement of the sori on the underside of the frond in parallel lines, a key feature of this genus.
Hart’s-tongue Asplenium scolopendrium emerging from an exterior wall
Moving on to another terrace, along another street lined with delightfully neglected student front gardens, there was one more species on the day’s agenda. Another Asplenium, though one that, in my experience, is typically harder to come by: Black SpleenwortAsplenium adiantum-nigrum. Unlike the wall specialists already encountered, this species is not a strict calcicole. Instead, it favours base-enriched substrates containing modest amounts of calcium or magnesium. For this reason, it is often found on mortared walls, though it grows equally well on natural rock faces and on ruins built from basic stone. It is common in many parts of Britain, but here in the North East, it is by no means abundant.
While it took some finding, after a short while, we managed to locate one small, rather pitiful example peeking out from a crevice. It will do for now!
A stunted example of Black Spleenwort Asplenium adiantum-nigrum on a neighbor’s wall
Running Total
Seeing as I rarely carry a notebook, we’ll log our running total for the year here…
It will come as no surprise to readers of this blog that I’ve developed a slight obsession with ferns of late, centred on both tracking down and identifying wild ones and growing them at home. Despite that, I hadn’t yet tackled the seemingly difficult process of growing ferns from spores. At least, not until this year.
Fern Biology
Ferns are among our most primitive plants, and their reproduction, while fascinating, is less sophisticated than that of flowering plants. Cutting a long story short, spores are produced on the underside of the frond in structures called sori (or a sorus if referring to just one).
Ferns are interesting in that they have two distinct life stages. The first is the gametophyte, or sexual stage, in which the spores grow into a curious, shield-like structure called a prothallus. It looks a bit like a tiny green fish scale and, in truth, rather resembles a bryophyte, but with minute pockets that hold the egg and sperm. When conditions are right, fertilisation takes place, with sperm swimming through water droplets to reach the egg of another prothallus. Only after this stage does what we think of as a “proper” fern develop, as the plant enters the second phase of its lifecycle.
Keen to try this myself – and having sufficiently swotted up with a range of fantastic resources online [here] and [here] – I decided to give it a go this summer. Time for an update!
Lemon-scented Fern Oreopteris limbosperma showing ripe spores in the pinnule margins
Gathering Spores
Ferns produce spores at different times of the year, though most seem to be ready between June and September. It’s fairly easy to tell when they’re ripe: in most species, the sporangia curl back or fall off entirely, revealing brown, yellow, or even black dust – the spores. Gathering them is incredibly simple. You can either tap a fertile frond over a paper envelope or collect a small section of the frond; a little goes a long way. If you choose the latter, it’s best to let it dry on some paper for a few hours, after which you’ll notice the spores beginning to fall and gather on the surface.
For this little experiment, I gathered spores from a mix of cultivated plants growing in the garden including Brittle Bladder-fern Cystopteris fragilis, Rustyback Asplenium ceterach, Soft Shield-fern Polystichum setiferum, Scaly Buckler-fern Dryopteris remota, and Beech Fern Phegopteris connectilis; as well as a few common wild species growing in public spaces (remember, you need permission to collect even the smallest hint of plant material from private land). In the end, this meant I collected spores from Western Scaly Male-fern Dryopteris affinis subsp. affinis, Borrer’s Male-fern Dryopteris borreri, and Maidenhair Spleenwort Asplenium trichomanes too.
Sowing the Spores
Having gathered our spores, it was time to sow them. This, it seems, is the stage you really need to get right. First, you need an airtight container that seals in moisture and provides the humidity required for the spores to germinate (we used a multipack of cheap plastic Tupperware). Secondly, you need a fine, sterilised compost. We opted for a fine seed compost, zapped in the microwave for three minutes to kill any nasties lurking in the soil. Other sources suggest that pouring boiling water through the compost or placing it in the oven works just as well.
With your materials prepared, all that remains is to sprinkle on your spores, give them a good spritz of water, label the container, and replace the lid before leaving it somewhere bright for nature to run its course. In our case, we placed all our containers under fluorescent grow lights used for our houseplants.
Watch and Wait
Next comes the hard part: ignoring your containers until you notice signs of life. I didn’t manage this perfectly, which may explain some of the problems mentioned later in this post. Generally, sources online suggest that different ferns take varying amounts of time before any activity becomes visible. I was pleasantly surprised that after only a month, each of our test containers hosted a fine, green, algae-like film spreading across the soil. This was the first sign that our spores were starting to grow into prothalli.
Beech Fern Phegopteris connectilis forming prothalli after one month under supplimentary light
Watch the Prothalli Grow
Eventually, after a variable amount of time depending on the species (around three to four months for most of ours), the initial green, algae-like growth began to transform into the shield-like structures recognisable as prothalli. At this stage, the fern grows its first roots and begins to photosynthesise, and it is also the point at which the all-important fertilisation happens, if you’re successful. To help with this, sources recommend a regular spritz of water to aid cross-fertilisation, something that would normally be provided by rain outdoors but must be administered manually when growing ferns indoors. The photos below show a range of more advanced prothalli.
After some time, these prothalli develop into the sporophyte generation, the form we most closely associate with ferns.
Borrer’s Male-fern Dryopteris borreri prothalliThe rather large prothalli of Borrer’s Male-fern Dryopteris borreri
Signs of Life
Fast forward to early winter and most of our ferns have now begun transitioning into their sporophyte generation. Some, such as Beech Fern and the larger Dryopteris species, are lagging behind, with only the tiniest hint of their first fronds visible. Others are positively romping away, particularly Brittle Bladder-fern which has already warranted the relocation of larger plants to individual pots (again in sealed containers) for growing on over winter. I have also been impressed with Soft Shield-fern.
As we now have so many young ferns growing in containers, we have broken with the usual advice that recommends leaving sporlings in place until they are large enough to handle. Instead, we have opted to split our batches, leaving some in situ while moving small clumps of prothalli to individual containers to see whether this results in healthier, more vigorous plants. All are being kept under plastic to retain that all-important humidity, but I have already begun removing the lids from larger specimens to gradually accustom them to harsher conditions, with the aim of moving some outdoors come spring.
The images below show various species as of 20 November 2026, which is not bad at all for spores sown in June and July.
Young Brittle Bladder-ferns Cystopteris fragilis potted up in Novemeber 2025 (sown in June)Transplanted Maidenhair Spleenwort Asplenium trichomanes with signs of new growthThe first fronds of Soft Shield-fern Polystichum setiferumRather congested Borrer’s Male-fern Dryopteris borreri
A Few Problems
While some of our ferns have been successful, others have failed miserably, and in most cases, this is entirely my fault. I mentioned earlier that you should ignore your spores for a prolonged period, something I confess I didn’t do, as too often I found myself opening the pots for a sneaky look. Doing this, it seems I allowed contaminants into the pots, resulting in mould that quickly overtook many of the young plants. We lost most of our Rustyback specimens this way, but I did discover that you can safely move prothalli to another jar, helping to preserve at least some plants.
Not sterilising the soil sufficiently may also have been a problem, as algae and bryophytes appeared in several pots, leading to competition with the young ferns. The greatest problem of all, however, seems to be overcrowding. It is all too easy to sow far too many spores in a single container, and when this happens, the added competition prevents the prothalli from developing properly. This is currently affecting our Dryopteris affinis containers, but I hope it can be remedied by thinning, just as you would with the seedlings of any other plant.
And with that, the first stage of the challenge is complete. I will post an update further down the line as we progress to potting on and eventually planting out. I am optimistic, as the whole process has been far easier and, dare I say it, quicker than I envisaged at the start. If you have ever fancied growing ferns from spores yourself, I would strongly recommend giving it a go. You may find it slightly addictive and end up with more than you can handle, just as we have.
As a quick further update since drafting this post, we ended up sowing spores from a range of other cultivated species, including Oak Fern Gymnocarpium dryopteris and Limestone Fern Gymnocarpium robertianum, as well as some Narrow Male-fern Dryopteris cambrensis gathered from an unassuming Northumbrian roadside. Being more ambitious, I am also attempting to hybridise Male-fern Dryopteris filix-mas with Borrer’s Male-fern to create Cryopteris × critica, but we will see how that pans out.
For our next plant profile, we’ll take a closer look at one of my favourite ferns – the delicate and beautiful Beech Fern Phegopteris connectilis. This is a rather uncommon species in the North East but one which I have been encountering more frequently thanks to my ongoing Big Fern Challenge. Now seemed like a good time for a closer look.
Beech Fern
Phegopteris connectilis
Beech Fern is not a species many of us will encounter regularly – unless you’re lucky enough to live in parts of Scotland or perhaps Wales.
This delicate and attractive fern tends to grow in special habitats, including ancient woodlands dominated by Sessile Oak and on shaded, humid gully sides where base-rich water seeps through. Locally, I have found it in both habitats, though the greatest concentrations are nestled among boulder scree in upland areas or tucked away in permanently damp, humid spots around waterfalls and burns. Beech Fern is known to be intolerant of grazing and is therefore often found in places out of reach of passing sheep or deer.
Surprisingly, it is seldom found under Beech trees as it avoids overly acidic substrates, favouring instead neutral to mildly acidic.
Beech Fern Phegopteris connectilis spotted at Hen Hole in the Cheviots
Upon further reading, I discovered that Beech Fern has a rather interesting history. It was first reported by Bobart as far back as 1699, who – using typically lengthy Latin – named it Filix minor Britannica pelliculo pallidore alis inferioribus deorsum spectantius. Quite a mouthful, but the name roughly translates to “a small British fern with pale green fronds and downward-pointing pinnae.” Even today, this description remains remarkably accurate!
The name Phegopteris connectilis is a combination of Greek and Latin terms. Phegopteris comes from the Greek words phegos meaning “Beech” and pteris meaning “fern”, describing a fern associated with beech trees. The specific epithet connectilis is Latin and translates “fastened together”.
Although uncommon in lowland areas, the distribution of Beech Fern is considered stable by the BSBI, with new sites being discovered on the edges of its Scottish and Welsh populations. While it may have declined slightly in England, it can still be found in most of its historic haunts.
Unfurling Beech Fern Phegopteris connectilis spotted at Hen Hole in the Cheviots
In terms of its associates, Beech Fern commonly grows alongside Oak Fern Gymnocarpium dryopteris in ancient woodland but in the uplands, may often be found alongside Brittle Bladder-fern Cystopteris fragilis on damp ledges, and in scree alongside Mountain Male-fern Dryopteris oreades.
Identification
Phegopteris connectilis is an easy plant to identify. It is a small, rhizomatous species that can form dense, spreading colonies in suitable habitats. Telling it apart from other ferns shouldn’t be a problem if you focus on a few key features.
Firstly, unlike any other British fern, the pinnae are winged – meaning they’re connected to the rachis along their entire length. This is the origin of the specific epithet connectilis.
Secondly, take a close look at the lowest pair of pinnae. These are opposite, backward-facing, and angled at about 90° to each other. They typically stand erect – resembling a pair of rabbit ears!
That’s all there is to it with this one.
Beech Fern Phegopteris connectilis at Hareshaw Linn, Northumberland
Distribution
In the North East, Beech Fern is an uncommon species. As the orange dots indicate, it hasn’t been recorded at many of its historic sites since the turn of the millennium.
Nevertheless, the species persists in several locations, with notable clusters in the Kielder and Cheviot areas of Northumberland, as well as in the North Pennines of County Durham. It can also be found along watercourses and in remnants of ancient woodland along the River Tyne, from Haltwhistle to Hexham.
Given the lack of recent records, it seems reasonable to conclude that Beech Fern has been lost from most lowland areas of the region.
Phegopteris connectilis in the The ferns of Great Britain and Ireland (Plate IV)
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 spotUpperside of the pinnules showing teethThe 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 #2and #3A more impressive dark spotFunnel-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 #4Dark marking extending up costaThe 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.
For our first plant profile, we’ll cover an unobtrusive yet beautiful little fern found in only a select few corners of North East England: Lobed Maidenhair Spleenwort.
This is an extremely rare plant that thanks to an unexpected trip to Hareshaw Linn in Northumberland, I recently had the chance to see for the first time.
Lobed Maidenhair Spleenwort
Asplenium trichomanes subsp. pachyrachis
Many of us are familiar with with Maidenhair Spleenwort (Asplenium trichomanes), the delicate, trailing fern adorning garden walls and other structures throughout our towns and cities. What you may not know, however, is that the UK is home to several subspecies of this lovely little fern, one of which is the Lobed Maidenhair Spleenwort (Asplenium trichomanes subsp. pachyrachis).
This unassuming fern grows on calcareous rocks such as limestone in shaded, humid settings. Often under rock overhangs, on steep valley sides or beside waterfalls, such as at Hareshaw Linn. Unlike it’s more familiar cousins, it is seldom found on mortared walls and is unlikely to crop up in towns.
A genuinely rare subspecies in the UK, Lobed Maidenhair Spleenwort is found at only a scattering of sites. A notable concentration can be found in south Wales, with a further cluster of records near Chester. Elsewhere, it is found sporadically in small populations at isolated sites.
This fern is widespread in Southern Europe, particularly in Spain, France and Italy, so may well be under-recorded in the UK.
The specific epithet trichomanes refers to a Greek word for fern
Lobed Maidenhair Spleenwort, spotted at Hareshaw Linn in Northumberland
Identification
Lobed Maidenhair Spleenwort is a small, tufted plant that often appears to grow flat against the surface of rock. Its narrow, green fronds are usually 5-30mm long and contain at their centre a dark, glossy mid-rib – a useful feature for seperating this group from Green Spleenwort (Asplenium viride). The pinnae or leaflets usually number in at 20-30 pairs and are arranged oppositely along the frond. All of this, however, appeals to other Maidenhair Spleenworts too, so what sets this subspecies apart?
The main difference between Lobed Maidenhair Spleenwort and other subspecies is the margin of pinnae. As its name suggests, those of this fern are distinctly lobed, almost scalloped. In contrast, those of other subspecies may be asymmetrical or rectangular but only slightly toothed. It may only be an anecdotal observation, but I think the lobes give the leaflets of this fern an arrow-like shape…
Given it’s similarities to other Maidenhair Spleenworts, it is little wonder this fern is poorly recorded. Sure, it may be rare, but it must be present unnoticed at further sites. Will you find it?
Distribution
In the North East, Lobed Maidenhair Spleenwort is restricted to just a few locations: one in South Northumberland (VC67) and three in County Durham (VC66).
In Northumberland, the most notable colony is found at Hareshaw Linn SSSI, where the species thrives on the humid rock faces surrounding the site’s waterfall. In County Durham, it has been recorded at two sites near Barnard Castle and on crags along the River Tees near Bowlees.
