Sphagnum platyphyllum | Flat-leaved Bog-moss



Conservation status

Future ProspectsN/A
Overall  Assessment of Conservation StatusInadequate
Overall Trend in Conservation StatusStable
*All E.U. Sphagnum species  are identified as requiring assessment under the Habitats Directive. Guidelines on reporting for the Habitats Directive indicate that these species are required to be reported on as a group, unless a member state is of the opinion that individual species within the group may require special attention. In the Article 17 Habitats Directive reporting for the period 2007-2012 none of the named Sphagnum species of the Habitats Directive occurring in Ireland were identified as requiring special attention.

The Conservation Status in the table above is then for the Sphagnum genus in Ireland rather than for the individual species.

Sources: NPWS 2013; European Topic Centre on Biological Diversity.

IUCN Conservation Status
Ireland (1)Near Threatened
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


Species Biology


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 branch leaf pores are = 6µm and, depending on species, 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.
Sphagnum platyphyllum, in addition to the characteristics outlined above may vary in colour from green to yellowish or olive green or beown or a mixture of these.

  • S. platyphyllum very rarely forms disctinct mats or hummocks, most often forming very loose mats or widely separated groups of stems.
  • In good growing conditions S. platyphyllum may measure to 1.5cm in diameter including fascicles.
  • Stem leaves to maximum 2.3mm in length.
  • Stem leaves may be appressed and orientated so the apex points up towards the capitulum, or may spread at an angle of up to 90° to the stem.
  • Stem leaves rather elliptical in shape and somewhat concave. Stem and branch leaves are quite similar in size and shape in this species.
  • Stems may be pale green or pale brown, but may seem black if stained by its growing medium.
  • Branch leaves are elliptical and concave, to a maximum 2.1mm in length.
  • Terminal buds in capitulum well defined and obvious.
  • S. platyphyllum has 1 to 3 branches per fascicle all of which look quite similar.
  • Well grown shoots to 15cm long.
  • Capsules never recorded in Britain or Ireland.
Sources: Atherton, I., Bosanquet, S., Lawley, M., 2010; Smith, A.J.E. 2004.


S. platyphyllum is the most base demanding species of the Sphagnum genus occuring in Ireland.

Habitats may include but are not necessarily limited to;

  • Rich fen and flush (PF1)
  • Transition mire and quaking bog (PF3)
Sources: Atherton, I., Bosanquet, S., Lawley, M.,  2010; Lockhart, N. et al, 2012a; Fossitt, J.A. 2001.


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'.
Source: NPWS 2013.

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.

Source: NPWS 201


World distribution(GBIF)

In Europe most records from Norway, including the far north, Sweden, Denmark, Finland, the Netherlands, Britain, Ireland and Iceland with scattered records from central Europe and Iberia and Greenland. Widespread but scarce records from North America. Also very scarce records from the north west of South America / Central America.

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

Rare and local records from Burren and the south west.

Temporal change

Records submitted to Data Centre in 2021

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 platyphyllum 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:

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



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. <>. Downloaded on 27 November 2014