Taxonomy
Sphagnum denticulatum | Cow-horn Bog-moss
Distribution
Status
Conservation status
| HABITATS DIRECTIVE ARTICLE 17 REPORTING* |
| Range | N/A |
| Population | N/A |
| Habitat | N/A |
| Future Prospects | N/A |
| Overall Assessment of Conservation Status | Inadequate |
| Overall Trend in Conservation Status | Stable |
Sources: NPWS 2013; European Topic Centre on Biological Diversity.
| IUCN Conservation Status |
| Ireland (1) | Least Concern |
| Europe (2)** | Not evaluated |
| Global (2) | Not evaluated |
**Although not published separately, an evaluation of 'Least Concern' at a European level is indicated in the Ireland Red List No.8: Bryophytes. This evaluation was carried out under the auspices of the European Committee for Conservation of Bryophytes.
Sources: (1) Lockhart, N., Hodgetts, N. & Holyoak, D. 2012; (2) The IUCN Red List of Threatened Species. Version 2014.3.
Legal status
Protected by the following legal instruments:
- Habitats Directive [92/42/EEC] Annex V
Native status
Native.
Species Biology
Identification
Members of the Sphagnum genus are distinguished from other moss species by the combination of the following, amongst other, characteristics;
- The absence of rhizoids in the gametophyte
- The presence of groups of spreading and / or pendent branches (these groups referred to as fascicles) arranged at intervals along the main stem.
- As well as chlorophyllose cells (chlorocysts) Sphagnum leaves have adapted large dead cells, 'hyaline' cells, that allow Sphagnum species plants to retain water in relatively large amounts.
- The sporangium lacks the peristome seen in many other moss genera.
- Rather than the seta (stalk) seen in other mosses, in Sphagnum species the spore bearing capsule is borne on a pseudopodium.
- The top end of the plant, where new fascicles are formed, contain many young compact fascicles which give Sphagnum species a distintive 'mop-head' look. This terminal head is termed a capitulum.
- The lack of a leaf mid-rib or 'costa'.
Sphagnum subsecundum is one of a group of five Irish Sphagnum species that are often referred to collectively as section Subsecunda. In this group the defining characteristics are primarily microscopic e.g. that the stem cortex is between 1 and 3 cell layers thick.
There are other characteristics that may aid identification in the field.
- Branch leaves are not conspicuously hooded at the apex.
- Stem cortex makes up rather less than 1/4 of the stem diameter.
- Either
the branches or the leaves are somewhat curved to follow the curve of
the stem core or branch core respectively ('secundum' indicates
'following' in this case a plane of rotation is being followed.)
- Branch leaves not markedly 'squarrose' i.e.suddenly bent back and away from branch stems, although branch leaf apices may bend to one side.
- Branch leaves are not markedly thin in comparison to length.
- Branch leaves do not become markedly undulate (wavy) or otherwise markedly alter appearance when dry.
- In some species (S. platyphyllum, S. denticulatum)
the spreading branches generally appear swollen, with a smooth outline
and are usually curved to one side to resemble cow horns. In these
species branch leaves near the base of branches are straight when viewed
from above.
- In contrast other species (S. subsecundum, S. inundatum, S. contortum), have spreading branches that appear swollen, with an uneven outline and may be straight or curved. In these species branch leaves near the base of branches appear curved to one side when viewed from above.
- In good growing conditions S. denticulatum may measure to 2.5cm in diameter, including fascicles although 1.5cm is more usual.
- Stem leaves to maximum 2.7mm in length although 2mm is perhaps more usual, which is a relatively large leaf size.
- Stem leaves may be appressed and orientated so the apex points down (away from capitulum), up towards the capitulum, or may spread at an angle of up to 90° to the stem.
- Stem leaves rather tongue shaped.
- Stems may be dark brown or, in shaded or submerged plants, green.
- Branch leaves are ovate, to 2.5mm in length and generally appressed and overlapping although some may be at an angle of 45° to the branch, and some may be turned slightly in the plane of rotation of the branch core.
- Branch leaves towards the branch tip, particularly in those branches towards the outside of the capitulum, are tightly appresseed and overlapping, giving those branch tips a rather pointed tip.
- When viewed from above branches towards the outside of the capitulum are distinctly curved to follow the curve of the stem core. This, with the pointed tips, gives these branches the 'cow-horn' appearance that inspires the common name.
- S. denticulatum has 2 to 3 spreading branches and 1 to 3 pendent branches although branches in fascicles on the stem further away from the capitulum may not be as clearly differentiated into spreading and pendent branches. When 5 branches are present in a fascicle a couple may be very poorly developed.
- Capsules produced occasionally, in the summer.
- Well grown shoots to 20cm long.
- Very variable in appearance depending on pH status, base enrichment and whether or not submerged, and microscopic examination may be necessary to determine to species level, particularly as shaded or submerged plants of this species, S. inundatum and S. subsecundum can be very difficult to separate.
Habitat
Genrally found in acidic conditions which may be very wet or drier but also found in moderately utrient rich situations with the particular conditions it is found in affecting its appearance.
Habitats may include but are not necessarily limited to;
- Bogs (PB)
- Poor fen and flush (PF2)
- Transition mire and quaking bog (PF3)
- Wet Heath (HH3)
- Montane Heath (HH4)
- Dystrophic Lakes (FL1)
- Acid oligotrophic Lakes (FL2)
- Non-calcareous springs (FP2)
- Oak-birch-holly woodland (WN1)
- Bog woodland (WN7)
- Conifer plantation (WD4)
- Exposed siliceous rock (ER1)
Sources: Atherton, I., Bosanquet, S., Lawley, M., 2010; Smith, A.J.E. 2004; Rodwell, J.S. (ed.) 1991; Hill, M.O. et al 1992; Fossitt, J.A. 2001.
Reproduction
Classic alternation of generations with diploid sporophyte and haploid gametophyte generations. In mosses the haploid gametophyte is the longer lived and obvious plant seen in the field.
The sporophyte is the capsule which is borne on a pseudopodium produced from tissue of the gametophyte.
Fertilization of female gametes by male gametes produces the diploid sporophyte. Meiosis of spore mother cells produce haploid spores, which are disseminated when the capsule opens. Spores germinate into a filamentous 'protonema' which will eventually produce the familiar moss gametophyte.
Sources: Porley, R. Hodgetts N. 2005.Sphagnum species can also spread vegetatively through the development of new stems from branches and may also spread via plant fragments.
Threats faced
In the Article 17 Habitats Directive reporting for the period 2007-2012 no current threats were listed for this species. In that reporting period the named Sphagnum species of the Habitats Directive occurring in Ireland were given an 'Overall Assessment of Conservation Status' of 'Inadequate' due to;
- 'The poor conservation status of the peatland habitats within which the majority of Sphagnum species occur'.
Conservation actions
In the Article 17 Habitats Directive reporting for the period
2007-2012 no Conservation Measures in place or in the process of being
implemented during the period were listed for this species.
Distribution
World distribution(GBIF)
Most records are European, from Britain and Ireland particularly, also the Netherlands, Denmark, Sweden and Norway, Iberia with scattered records from central and eastern Europe with some also from Iceland.
Accuracy of world distribution shown in the Global Biodiversity Information Facility (GBIF) map below will be constrained by, amongst other factors, data held but not shared by countries and organizations not participating in the GBIF.
Irish distribution
Widespread in Ireland but recorded far more in the west and north than in the centre and the south eastern quarter of the island.
Temporal change
Records submitted to Data Centre in 2024
The following map is interactive. If you would prefer to view it full screen then click here.
How can you help
The National Biodiversity Data Centre is trying to improve our knowledge of the distribution of Sphagnum denticulatum in
Ireland. Should you observe this species, please submit sightings to
add to the database. Detailed observations will assist us gaining a
better insight into where the species
is most abundant in Ireland and we might also be able to detect
regional variations. Please submit any sightings and photographs at:
http://records.biodiversityireland.ie/
All
records submitted online can be viewed on Google Maps – once checked
and validated these will be added to the database and made available for
conservation and research.
Further information
For further information contact Dr. Liam Lysaght llysaght@biodiversityireland.ie
References
Publications
Atherton, I., Bosanquet, S., Lawley, M., 2010. Mosses and Liverworts of Britain and Ireland a field guide. British Bryological Society.
Fossitt, J.A. 2001 A Guide to Habitats in Ireland. The Heritage Council.
Frey, W., Frahm, J.P., Fischer E., and Lobin W. 2006. The Liverworts, Mosses and Ferns of Europe. Harley Books, Colchester.
Hill, M.O., Preston C.D., and Smith A.J.E., 1992. Atlas of the Bryophytes of Britain and Ireland Vol. 2 Mosses (except Diplolepideae). Harley Books, Colchester.
Holyoak, D. T. (ed.). 2003. The distribution of bryophytes in Ireland: An annotated review of the occurrence of liverworts and mosses in the Irish vice-counties baseed mainly on the records of the British Bryological Society. Broadleaf Books, Wales.
Lockhart, N., Hodgetts, N. & Holyoak, D. 2012. Ireland Red List No.8: Bryophytes. National Parks and Wildlife Service, Department of Arts, Heritage and the Gaeltacht, Dublin, Ireland.
Lockhart, N., Hodgetts, N. & Holyoak, D. 2012a. Rare and Threatened Bryophytes of Ireland. National Museums of Northern Ireland.
Porley, R. and Hodgetts N. 2005 Mosses & Liverworts, Collins.
Rodwell, J.S. (ed.) 1991. British Plant Communities Vol.2 Mires and Heaths.Cambridge University Press.
Smith, A.J.E. 2004. The Moss Flora of Britain. Cambridge University Press.
The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 21 November 2014