Fern Finds 2014: G. Garnett Coed Felinrhyd The Temperate Rainforests Along the west coast of Britain are a series of very special woodlands named Atlantic Oak woodlands, Coed Felinrhyd is one of these. The warming effect of the Gulf Stream combined with the high rainfall and humidity typical of the area forms the perfect habitat for an extraordinary number of flora and fauna species. In terms of flora Coed Felinrhyd is richest in lower plants and ferns thriving under a canopy of Quercus petraea and Betula pubescens As well as being biodiverse the woodland is also incredibly beautiful, with ferns, mosses, lichens and liverworts coating the trees and rocks and continuing downwards forming an emerald green carpet on the forest floor. Thelypteridaceae Phegopteris connectilis (Michx.) Watt On entering the forest we came across a large creeping mass of this unmistakable deciduous fern growing on a mossy rock. Throughout the walk we only came across one more colony, growing in similar conditions to the first. This fern features a triangular, bipinnate frond up to 40cm arising singly from a thin, creeping rhizome, the pinnules are entire and the whole topside of the blade is covered in small white hairs. The dark petiole is about twice as long as the blade. Unlikely to be confused with any other fern species. The sori are circular and indusia are absent. Dryopteridaceae Dryopteris aemula Kuntze and Dryopteris dilatata (Hoffm.) A.Gray Hay Scented Buckler Fern and Broad Buckler Fern We came across these ferns growing very close to each other. Both are similar, a possible source of confusion. D. aemula is evergreen has much smaller fronds, up to 60cm compared to 150cm fronds of D. dilatata. Another difference is the presence of a dark stripe up the centre of scales of D. dilatata, this feature is lacking in D. aemula. The most recognisable feature however is the margins of the pinnules being upturned and in many cases slightly overlapping, compared to D. dilatata which has the pinnules curled under at the margins. As the vernacular name suggests, D. aemula smells of hay. Many claim they cannot smell this however so it should not be trusted as a reliable identification feature.

Hymenophyllaceae Hymenophyllum tunbrigense (L.) Sm. and Hymenophyllum wilsonii Hook. Tunbridge Filmy Fern and Wilson’s Filmy Fern Hymenophyllum wilsonii was found growing in deep shade on a boulder at the top of the valley, close in proximity to the main waterfall in the forest. The colony spanned the entire boulder, spreading on a thin, creeping rhizome. There were also other colonies nearby, again on boulders and some clothing the base of trees. Growing further down the valley in slightly less abundance was Hymenophyllum tunbrigense. This species grew on the base of Betula pubescens, covering entire portions of the lower trunk in a dark translucent green. Sadly on one tree a large proportion of a colony had been destroyed by a dog urinating on it, an unfortunate death showing just going to show how sensitive to environmental change this genus is. As the two species were growing in the same forest, it was necessary to learn how to differentiate them, easier said than done! The best way to differentiate the two is by studying the indusium, H. wilsonii has an entire margin to the indusium valves and overall the indusia are more ovoid than in H. tunbrigense. The two species also differ in the position of the indusia, H. wilsonii has the indusia projecting outwards from the frond margin whereas indusial of H. tunbrigense do not project out of the frond margin. Other differences are seen in the shape of the frond and the venation, H. wilsonii having a narrower frond with 3-5 lobes situated on one side of the rachis. H. tunbrigense has 5-11 lobes that are spread more evenly on both sides of the rachis. In H. wilsonii the veins reach the tip of the lobe, in H. tunbrigense the veins do not quite reach the tip of the lobe. Dryopteridaceae Polystichum aculeatum (L.) Roth Hard Shield Fern Polystichum may be confused with Dryopteris, to tell the two genera apart remember: Polystichum has peltate indusia, Dryopteris has reniform indusia. We found this species scattered around the base of the waterfall; a large evergreen fern with glossy, dark green fronds, some reaching nearly a metre long. This was the only species of Polystichum growing in the forest, it can however be confused with Polystichum setiferum which tends to have lighter green fronds that are not as glossy. Another useful identification feature is that the lowest pinnae on P. aculeatum are about half as long as the middle pinnae whereas on P. setiferum the lowest pinnae are about the same length as the middle pinnae.

Hymenophyllum tunbrigense

Dryopteris dilatata

Polystichum aculeatum

Hymenophyllum wilsonii

Dryopteris aemula

Coed Felinrhyd Waterfall

Osmundaceae Osmunda regalis L. Royal Fern We found this scarce species growing low down in the valley growing very close to a large stream. This is probably the largest of all our native ferns. The bipinnate sterile fronds can grow up to 2 metres long and are easily identifiable by their light green colouring and numerous entire pinnules. The fertile fronds are upright and arise from the centre of the plant. These fertile fronds are made of a few pairs of basal sterile pinnae, above these are numerous pairs of narrow pinnae decreasing in length and covered in sporangia. Thelypteridaceae Oreopteris limbosperma Lemon Scented Fern This fern was scattered near the edge of the woodland where it received slightly more light. The deciduous fronds are yellow-green in colour, generally only reaching about 100cm in length. The fronds are lanceolate and bipinnate with up to 30 pinnae and entire pinnules. On the fertile fronds are the small sori, the indusia are obscure or even absent. When crushed, the frond emits a pleasant lemon smell. Many people claim not to be able to smell it however, so this is a bit of an unreliable identification feature.

Disused Lead mine in Gwydyr Aspleniaceae Asplenium septentrionale (L.) Hoffm. Forked Spleenwort This peculiar looking species was growing in well drained rocky soil in a former lead mine. Due to the exposed conditions and the presence of heavy metals, very few other species grew there. This fern was thriving however. It grew forming large clumps in gaps between the rocks. The long stipe is a dark glossy brown and gives way to a shorter stiff, irregularly forked blade that only reaches 2-4mm in width. The linear sori are almost as wide as blade segment and are protected by a similarly shaped indusium. Asplenium adiantum-nigrum was also present, though there was no sign of the hybrid, Asplenium x contrei.

Cwm Idwal The search for Asplenium viride. Cwm Idwal is a glacial valley that was formed during the last Ice Age. At the bottom of the valley is the lake, Llyn Idwal, surrounding this are a number of mountain ridges. We followed the path around the lake, taking in the stunning scenery and admiring the incredible biodiversity. Towards the eastern end of the lake the path started become steeper, after crossing a relatively fast flowing stream, we began to see the large boulders that Asplenium viride grew on. Aspleniaceae Asplenium viride Huds. Green Spleenwort Found growing all over the large calcareous boulders surrounding the path. It appeared that this small evergreen species needs some altitude in order to grow. A. viride looks superficially similar to the more common A. trichomanes but differs in having a green rachis instead of a black rachis. The blade can grow to about 15cm and is made up of a wingless rachis, along which, there are numerous pairs of small, ovate, toothed pinnae. The sori are linear and are protected by slightly toothed, linear indusium. Cystopteridaceae Cystopteris fragilis (L.) Bernh. Brittle Bladder Fern Growing abundantly on the same boulders as Asplenium viride, was what we originally thought was Woodsia alpina, seeing what we thought, was this rare species was incredibly exciting. About three weeks later however, we realised that perhaps it wasn’t Woodsia alpina after all. Both species have a lanceolate blade and are variable in size. Dr Fred Rumsey gives the best description of the distinguishing characteristics between Woodsia alpina and Cystopteris fragilis: “There are boreal forms of Cystopteris, usually with the dickieana –type spores which really do look very similar to Woodsia and often grow with them. They are a real pain to tell apart – although somehow Cystopteris always seems to have a thinner texture to the frond. Woodsia fronds break off above the surface of the substrate – leaving a distinct stalk up to a cm long with a clean broken end. An old plant will have lots of these projecting pegs and that can help tell them apart. Usually you can tell Woodsia alpina because it’s a much smaller plant with much shorter more obtuse pinnules. So the frond is quite narrow.” Cystopteridaceae Gymnocarpium dryopteris (L.) Newman Oak Fern

Found growing in a gap between two boulders. This deciduous species has small delicate 3-pinnate fronds that are a bright lime green colour. The blade is triangular, along it are about six oppositely arranged pinnae. The green rachis joins on to a long greenish yellow stipe, often growing as the long as the blade. The species spreads by a creeping rhizome. The small sori are round and are not protected by indusia. Selaginellaceae Selaginella selaginoides (L.) P. Beauv. ex Mart. & Schrank Lesser Clubmoss I don’t recall much about seeing this species, I believe it was growing in a grassy patch in the boulder field. This particular plant was erect not creeping. The species is evergreen and rather small as can be seen in the photo (about 40mm). The spirally arranged microphylls are very small (3mm) and feature a number of spiny teeth on the margins. The strobilus is terminal and sessile containing few megaspores but numerous microspores. Lycopodiaceae Lycopodium clavatum L. Stag's-Horn Clubmoss This evergreen species grew on the grassy areas on each side of the track leading up to the boulder field. It formed a large branched plant, creeping and rooting at each node. The spirally arranged microphylls reached up to 5mm. There were no fertile branches on the plants we saw.

Llyn Idwal

Lycopodium clavatum

Selaginella selaginoides

Diphasiastrum alpinum

Asplenium viride

Cystopteris fragilis

Identification of the parent species Before attempting to identify the hybrids it is important to be able to identify the parent Asplenium species of which the hybrids are intermediate. Asplenium adiantum-nigrum and Asplenium obovatum appear superficially similar, both having 2-3 pinnate fronds. They can however, be differentiated by other morphological characteristics. Asplenium adiantum-nigrum fronds are triangular in shape whereas A. obovatum has fronds that are lanceolate in shape. Another key difference is the arrangement of the sori on the underside of the pinnae, A. adiantum-nigrum sori are arranged close to the centre of the pinnule, in A. obovatum the sori are arranged near the margin of the pinnule. The new fronds of the two species are also useful in identification. A. adiantum-nigrum pinnae start off swept upwards at an angle. A. obovatum pinnae, on the other hand, start off curled under at the margins. Asplenium scolopendrium is rather eas to identify and is unlikely to be confused with any other British native fern. It is evergreen and has a simple, lanceolate, glossy frond with an entire margin and auriculate base.

Ecology of the parent species Asplenium adiantum-nigrum This species can tolerate a wide range of conditions and can be found in acid soil in hedgebanks and cracks in granite walls. Asplenium obovatum This species will not tolerate alkaline conditions, as a result of this it generally does not grow on the walls in Guernsey. It occurs predominantly in hedgebanks where the soil is acidic. Apparently the two species are similar in that they both need “damp but well drained edaphic conditions” (Gibby, et al., 1996).

The hybrids A hybrid by its very nature, is an intermediate between its parent plants, because of this, every plant will look slightly different, this can pose a problem in identification and so an effort has been made to show the most consistent identification features for each hybrid as well as pointing out the differences between juvenile and adult forms. Asplenium x microdon Guernsey Fern A hybrid between Asplenium obovatum ssp. lanceolatum and Asplenium scolopendrium; from personal observation this appears to be the most common of the three hybrids, it is also probably the easiest to identify.

The frond is lanceolate in shape averaging about 20cm in length and on new fronds the pinnae are curled under at the margins these are obvious signs that A. obovatum is part of the parentage. A. scolopendrium can be seen in the entire or shallowly lobed pinnae margins and the glossy lime green colour to the frond. All of these features are consistent from plant to plant. The pinnae themselves almost look like small A. scolopendrium fronds. Young plants are neater looking due to the smaller, more regular elliptic pinnae. Larger plants have longer lanceolate pinnae, often with crisped margins on the larger pinnae. At the end of the frond, most plants, regardless of age have at least some pinnae conjoined to each other and to the rachis. The sori are linear and are arranged on the bottom of the pinnae in a similar way to that of A. scolopendrium.

Asplenium x sarniense Guernsey Spleenwort This is a hybrid between A. adiantum-nigrum and A. obovatum. It looks extremely similar to A. adiantum-nigrum. Generally the fronds are triangular rather than lanceolate and the sori are arranged up the centre of the pinnule. For these reasons the A x sarniense is often dismissed as being A. adiantum-nigrum, or overlooked completely. The most effective way of differentiating it from the parent species in the field is to observe the newly flushing fronds. Although the plant may look like A. adiantum-nigrum, often the new fronds are curled under at the margins just like A. obovatum. If a plant is suspected of being a hybrid it can be confirmed by checking under a microscope for the characteristic abortive, misshapen spores.

Asplenium x jacksonii Jackson’s Spleenwort A hybrid between A. scolopendrium and A. adiantum-nigrum. The rarest of the three hybrids, personally I have only seen it in herbarium specimens. It does occur in the same habitats as the other two hybrids and is still being found however, which gives me hope in finding one in the wild. Morphologically, it looks similar to A x microdon. It differs from this species in having a triangular frond rather than a lanceolate frond (for obvious reasons). Also the basal pinnae are often quite long and really do look like miniature A. scolopendrium fronds! The only other obvious difference I have observed is that the frond is generally much smaller than A x microdon.

Bibliography Gibby, M., Rumsey, F., Vogel, J. & Paul, A., 1996. Conservation of Guernsey's rare ferns, London: The Natural History Museum . Jermy, A., Rumsey, F. & Vogel, J., 1998. BSBI Asplenium Crib. [Online] Available at: http://www.bsbi.org.uk/Asplenium_Crib.pdf [Accessed 25 July 2014].

About the herbarium My personal herbarium was created purely for fun; soon, however, I realised that it also had a more practical use. Sensible collecting of herbarium specimens and writing the accompanying notes is a really good way to learn more about the species and its habitat and personally, has helped me far more than just reading about the species after seeing it in the field. Of course it is also a great resource to have and is put to use frequently in identifying and comparing species. I do set myself some rules when collecting to ensure no damage is done to the population and in most cases, to avoid damaging the plant itself. The population must have at least 15 plants OR the plant must be of a substantial size. Try not to uproot any plants however on some occasions this is necessary, in these instances the population must be >20. Never pick threatened plants, even if the population is large. Picking threatened plants for a personal herbarium is illegal and unethical. Write good notes in the field, a herbarium sheet without good notes can be useless and does not provide a good record. These are a short set of personal rules, for more detail on collecting: http://bsbi.org.uk/Collecting.pdf