SATURDAY 11th JANUARY 2014          GLENMALURE, CO. WICKLOW

LEADER: JOANNE DENYER

MOSSES AND LIVERWORTS

               A joint DNFC / British Bryological Society (Dublin Group) Event

On Saturday morning, the meeting place at Barravore was packed with cars, and people bristling with excitement. Every DNFC / BBS joint event is popular and well attended, and this outing was no exception. However, the majority of those present were awaiting athletes finishing The Art O’Neill Challenge.  

Extricating ourselves from the crowd, we crossed the river by the footbridge to the track in Glenmalure Valley. There Joanne gave a brief introduction to bryophyte morphology and stated that during the day, as well as examining a wide variety of upland mosses and liverworts, an attempt would be made to re-find the rare liverwort Southbya tophacea. This had not been seen in the Valley since 1988 when it was recorded near the Crusher House, a relic of the area’s mining era.  

Atrichum undulatum, found on the side of the track, was the first species examined. It has long pointed, toothed leaves with the nerve ending in the leaf tip. It is one of the most distinctive acrocarpus mosses, but it can resemble Mnium hornum in whose presence it is often found. Pogonatum aloides was growing nearby. It is a common moss of acidic soils and has reddish stems and triangular leaves. It can be distinguished from other Pogonatum species by its capsule.  

The next species considered, Racomitrium aciculare, was growing on a bolder. Racomitrium mosses can be difficult to identify, but Racomitrium aciculare is the only one without hair points that has toothed, nerveless leaves with blunt tips. As we progressed further along the track, Joanne spotted the pointed leaves and spear-like shoots of Calliergonella cuspidate, one of the commonest and easily recognized mosses. Typically, it forms large patches on tracks and paths, but it is also frequently found in lawns. 

Leaving the track and heading over marshy, boggy ground towards the Crusher House, some time was spent examining a growth of Hypnum cupressiforme on the base of a tree trunk. Hypnum is a difficult genus where a definitive identification is often based on the shape of lid on the capsule. H. cupressiforme is an upland species characterized by curved leaves with pointed tips, and a capsule with a beaked lid. Here too, we found Pleurozium schreberi with its bright red stem and convex, translucent leaves.  

At first glance, a small colony of Polytrichum commune resembled Pogonatum urnigerum, however, the latter is quite glaucous which distinguishes it from Polytrichum species. As the day progressed, we saw many of the more typical large hummocks of the tall, wiry, robust Polytrichum commune, Ireland’s largest moss, with its toothed, narrow pointed leaves that spread away from the stem. Many of the specimens seen were in fruit, the latter being a useful aid when separating Polytrichum species.  

In the vicinity, we admired a frozen patch of Hylocomium splendens that lived up to its name with its red stems and bi-pinnate, fern like leaves. Rhytidiadelphus triquetrus was conspicuous by its large, bushy form and leaves sticking out in all directions giving it a pale, chaffy appearance. This is a moss that also grows in calcareous woodland unlike Rhytidiadelphus loreus, encountered later, which is more of an Atlantic upland species and whose leaves curve backwards. Here too we identified the ubiquitous liverwort, Lophocolea bidentata that smells like rotting wood.  

Adjacent to the Crusher House we explored a stonewall on which, among other species, the liverwort-like moss, Fissidens dubius was evident. It is a frequent inhabitant of dry limestone walls and on its surface patches of calcium had precipitated.  Attempts to locate the elusive Southbya tophacea proved unsuccessful. Attention then turned to the outside wall of the building where, a nice clump of the very variable but strongly calcicole, yellow-green Ctenidium molluscum was spotted. The latter’s presence is an indication that “nicer species” may be located nearby. Also on the wall in the presence of Asplenium trichomanes, we noticed, the aptly named liverwort, Plagiochila asplenoides. The latter can be recognized by its convex leaves, bright pale green appearance, and translucent sheen. Inside the Crusher House a huge sheet of the thalloid liverwort Pellia endiviifolia was on view and, intermixed with it, the small, tree-like Plagiomnium undulatum with its characteristic tongue shaped, wavy leaves.  

It was now early afternoon and lunch beckoned. To avail of a sunny location in the Fraughan Rock Glen for our repast, we made an appetite-inducing climb from the lower ground of the Valley to the track leading to the Glen. On the slope, we were thrilled to find Saccogyna viticulosa, lurking in a damp, shaded place. This is a western oceanic species whose only redoubt in the east of Ireland is County Wicklow. It also happens to be one of the few liverworts with opposite leaves.  

Although we located some Sphagnum fimbriatum along the way, in many instances frozen species of Sphagnum capillifolium and Sphagnum fallax bore a remarkable resemblance to it. Alongside this upper track, Breutelia chrysocoma another species, which is more at home in western mountainous areas with a high rainfall, grew in profusion, as well as other mosses such as Sphagnum denticulatum, Nardia scalaris, and Bryum capillare.  

After lunch, we examined and recorded bryophytes in the vicinity of the stream. These included Scarpania undulata, which was detached from stones in the water, and Andreaea  rothii, which formed black, patches on the wet rocks. As we made our way back to base, Joanne, having given us a master class in bryology, continued to record a wide variety of species, proving her earlier remark that tracks can support a prolific range of mosses and liverworts.
Pat Lenihan 

 

     

Hypnum cupressiforme                  Andreaea rothii                  Ctenidium molluscum

         

   Calliergonella cuspidata                      Polytrichum commune              Racomitrium aciculare

          

Pogonatum aloides                                      Breutelia chrysocoma                              Pellia endiviifolia

     

Plagiomnium undulatum                                  Plagiochila asplenioides                              Saccogyna viticulosa

 

 

Photographs © P Lenihan 

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