LoughAllenBasin.com: Trips around Lough Allen (No. 12)

This is one of several pages published under this heading by LoughAllenBasin.com We endeavour to highlight what this area of North West Ireland has to offer as a place to live, a place where interesting Plants and Animals may be found, and as a quiet peaceful location for Hi Tech Enterprise.

(You are welcome to use our Ideas and Images but would appreciate acknowledgment of source. The vast majority of material published here is produced in house. LoughAllenBasin.com is an independent scientific effort with no commercial goal and aimed solely at conservation and protecting a part of Ireland’s valuable Heritage.)

BACK (to Index for this Section.)      NEXT Topic (......)    Lough Allen Basin HOME

12. Royal Fern (22nd April 2011)
Primitive... historical... unusual... a significant Lough Allen plant


Location:  Mainly north Lough Allen near the Shannon entry into the Lake.

An amazing large and ancient FERN found at Lough Allen:

Royal Fern is Ireland’s largest fern. It can be a very prolific and impressive species, growing taller than the height of a person. It has one striking colony in a restricted area of north Lough Allen. It is very undisturbed here and seems to be thriving. However, it is a beautiful species and needs to be both appreciated and understood.

Though recorded as being fairly common in the north west of Ireland, this occurrence which we describe here is the only large area of Royal Fern around Lough Allen. These photographs were taken last year, and in 2009, from June to September.

Royal Fern requires very specific conditions if it is to thrive. Its presence here is a sign of an intact environment with ideal growing conditions and little disturbance over many years. Long may Lough Allen be able to provide such conditions for its notable Flora and Fauna and for the people who know and appreciate the area.

Very small outlying groups of plants (or individual plants) do occur around the east and north shores of Lough Allen but they rarely seem to amount to much. Either the local conditions, or Lough Allen’s notoriously changing water levels, mitigate against other large colonies being formed. However this colony is sizeable, intact, and evidently thriving. It is, by virtue of its location, largely unaffected by changing water levels in the lake as a whole and this may be the key to its survival in this one stronghold.

We are unfamiliar with Royal Ferns distribution in the wider Leitrim area and would be very interested in reports from other fans of this species. The old lane separating the Royal Fern marsh from the River Shannon is shown on the left. A section of the colony in Autumn is shown above.

In Ireland, Royal Fern occurs over most Western areas, from north west to south west, with a small concentration also occurring in the south east. It seems to be much less common in the east and midlands. Worldwide, this species is quite widespread, occurring in North, Central and South America; Asia and Africa. However it’s not found in Australia or New Zealand. In Scotland, Royal Fern numbers are declining, (Dumfries and Galloway Co. Council report 2002) due to drainage, sheep farming,and over-collection of specimens for gardens.






Here is a frond of the Royal Fern, showing its bipinnate structure. The pinnae, or leaflets, arise from the central stem, and are subdivided into smaller pinnules.

This is a sterile frond, not involved in plant reproduction, These fronds can be over a metre long.


Local Distribution

Royal Fern, in the right conditions, can form large colonies and always grows near water, along rivers and streambanks, in boggy areas, where the rhizome has access to water. It is less common in wet grasslands,  and is rarely found in open positions or on sand or gravel soils. However, in Boora Parklands, Co. Offaly, new individual plants have become established on the cutaway bog.

This young plant has become established in a stony area close to Annagh Lough and is probably less than 30cm tall. (The daisy-like flower growing next to it is Sneezewort.) There are some small, developing colonies of Royal Fern around this lake, but nothing as extensive as the main colony.




Name and History.

The origin of this fern's name (Osmunda regalis) is may derive from the Saxon God 'Osmunder' (the equivalent of the  Germanic God, Thor), Another possibility is that it was named after King Osmund, who reigned over the South Saxons about 758 A.D. If this is true, the species name, regalis, meaning royal, would then be obvious.  It might also be a simple classical description of a charcteristic of the species. In Latin ‘os’ (= mouth) and ‘munda’ (= clean); it was reputedly used to clean the mouth.

A fossil sporangium and spores of Osmunda regalis were found in sediments dated to about 9500 years old on the island of Utsira, SW Norway. The ages of these  remains indicate that Osmunda came into Norway, perhaps from Britain, during the first 1000 years of the  Holocene.

The family to which the Royal Fern belongs (Osmundaceae) is an isolated group unrelated to other ferns. Fossils of primitive ancestors of Royal Ferns have been found which are estimated to be between 289 and 248 million years old. Fossils of modern Osmunda (like the Royal Fern) have been found in Cretaceous sediments dated at about 65 million years!


Life History.

The Royal Fern is unusual in that it forms new fertile  fronds in autumn, and not in spring or summer as is common in most  ferns. The image on the right shows the outer bipinnate fronds with the tall fertile fronds towards the centre of the plant. The upper part of these fertile fronds (which are sometimes mistaken for flowers) contain thousands of tiny sporangia which in turn house the spores, the reproductive elements. Here, the spores are unripe, and green.

When ripe, (usually from June to August) the upper part of the frond turns reddish-brown and the sporangia fly off the plant when disturbed, releasing the spores. Each mature plant can release as many as 100,000 spores, so in a colony like the one here at Lough Allen, there will be millions of spores being released during a short space of time.

However, in contrast to other fern species, Royal Fern spores only live for 2 days, so they need to find suitable habitat quickly. However, spores are very light and are dispersed by the wind. This is a reason why new plants can often be found quite far from the ‘parent’ plant.

In most other species of fern, the spores appear on the underside of the frond in little round clusters called Sori.

Royal Fern habitat:

These 3 photographs show the habitat, the local geography (if you like), in which this striking Fern has settled and now thrives. In the wet and rushy area Royal Fern grows well. It is the dominant large plant but associated with  Alder and Willow.

A very short distance away, in grassland, no Royal Ferns occur. The trees are well established here and  the ground has risen above the water level and is too dry for the Ferns.




Below is a shot taken from the rough grassland looking west towards the permanent wetland where a wall of Royal Fern defines the change in geography. Behind the Ferns small trees have become established along the lane built alongide the wet area.

Other attractive Plants that thrive in this Habitat:

Marsh Cinquefoil

A five-leafed flower signifying hope and joy. Cinquefoils were held by the ancient heralds to represent various flowers according to the colours which they bore.

A beautiful and unusually coloured star-shaped flower which can be seen from May to July. It is widespread in Ireland, and locally common. The crimson sepals are contrasted by thin pointed purple petals, in a most uncharacteristic set of colours for a native plant.

Leaves are aranged in groups of 5 like fingers on a hand, and this explains their heraldic french name (= ‘five leaves’).

This species is also related to both Wild and Garden Strawberries.



Also known as Flags, this is the sole ‘Iris’ native to Ireland though many introduced varieties, in many colours, can be found. The Yellow Flag is a very common plant of wetlands and wet grassland.

A common plant throughout Europe, its striking flowers can be seen from May to July. It can spread to form dense stands, but drainage of land will control its growth.  It has a most beautiful flower, the delight of photographers. Look out for examples with beads of water on their petals after an early Summer shower.

Interestingly, not far from here, a very rare cousin of this plant exists. Also a member of the Iris family (but not the  ‘iris’ genus), the Blue-eyed Grass (so called) occurs in significant quantities at one part of the north shore. This important rare species is described HERE.





 Common Valerian.

A tall common plant of both wet and dry woodlands and grasslands.

We just love the variegated pinks and whites typical of the fresh flowers of this species.

Close up of a Hairy-cap Moss (Polytrichum spp.)

This moss grows in wet and boggy areas, forming large soft (and wet!) cushions on the ground. Typical in the habitat where Royal Fern are found, this moss can grow into quite large, spreading colonies, sometimes up to 25cm, depending on how wet the ground is.

The so-called caps, shown on the left, are Sporangia and these burst and release their spores when mature.

Heath Spotted Orchid

Same species also in the picture on the right, but a very different colour! We have worked hard to get this colour right and to the best of our recollection this represents the colour as seen in deep shade. In bright sunshine these specimes were showing a rosy tint but it was the lavender colour that attracted us to them.

To be technical, red/blue colour balance in Orchids is notoriously tricky to reproduce. This image was taken on a sophisticated camera and, being aware of the issue, we worked on the white balance to accurately render these unusual specimens. You will note that the green vegetation has come up similarly in both images. Photographic images of orchids like these can vary enormously depending on light, exposure and white balance, and it is always advisble to hold your playback image on the camera next to the orchid to check for colour matching!

Magnificient Tall Orchids.

One of Ireland’s commonest orchids, a delight to see on roadside verges, woodlands and meadows. Often found intermingled with the Common Spotted Orchid (its close relative) the Heath Spotted Orchid is an attractive and highly photogenic flower. You can find many colour varieties of this orchid, from almost white, to pink to violet. The dark green leaves have grey spots, and are easy to see when you are searching for orchids, even before the flower has come out.

These magnificient specimens were found along the lane running south parallel to the Shannon, with the Royal Fern to the East and the Orchids in dense woodland leading down to the river.

Up to 40cms. high and growing in groups, they were mainly located in a shaded but fairly bright location adjacent to the lane. Specimens as good as these are hard to come by. The wet, shaded and undisturbed area must be suiting them?





Four spotted Chaser.

In among all the flowers, we were struck by this peaceful fella enjoying a bit of sunshine! The Four-spotted Chaser is a sturdy Dragonfly common in Ireland. Bogs and fens and marshy areas near water are amongst the best places for these insects. If you stand quietly and watch for a while, you may be rewarded by the sight of some of these magnificent flyers. They dart around, searching for prey, sometimes hovering like a hummingbird, often coming back to rest on a favourite ‘perch’.

Dragonfly larvae live for many years as aquatic insects... in ponds, lakes and boggy pools. When they are ready to change, they develop soft wings and emerge onto vegetation by the water. Here, they will rest for a while, letting the wings lengthen and strengthen, and then they are ready to fly.

Adult dragonflies require good feeding areas so sites with additional habitats such as woodland, scrub or unimproved grassland and wetland vegetation close to breeding sites will support the strongest dragonfly populations. Just what we have here in the Royal Fern patch!

A farewell to the Royal Fern patch, but we will be back:

This amazing mixture of Orchids of many colours looked beautiful in among the grasses and horsetails with Willows providing the shade  and part of the large colony of Royal Fern starting to appear in the background. So many people nowadays are renewing their interest in Natural History, Photography, and Painting... this is a wonderful location for them and perhaps a potential  tourism attraction for serious artists and students of nature?




[MORE TRIPS to come! If you have any interesting records of animals or plants from the Lough Allen basin, or want to write
about your experience of Nature in this area, we will be very pleased to reproduce them here.]