Taxonomy

Sphagnum flexuosum | Flexuous Bog-moss

Distribution

Status

Conservation status

HABITATS DIRECTIVE ARTICLE 17 REPORTING*
RangeN/A
PopulationN/A
HabitatN/A
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.

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

IUCN Conservation Status
Ireland (1)Vulnerable [D2]
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, and 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, contains many young compact fascicles which give Sphagnum species a distintive 'mop-head' look. This terminal head is called the capitulum.
  • The lack of a leaf mid-rib or 'costa'.
Sphagnum flexuosum is one of a group of 6 Irish Sphagnum species that are often referred to collectively as section Cuspidata.

In this group the defining characteristics are primarily microscopic however there are other characteristics that may aid identification in the field.

There are other characteristics that may aid identification in the field.

  • Branch leaves are not conspicuously hooded at the apex.
  • Branch leaves not noticably toothed at edges.
  • Stem cortex makes up rather less than 1/4 of the stem diameter.
  • Stem leaves usually with a distinct border to the base.
  • Stem leaves may be appressed and orientated so the apex points down and away from  the capitulum, or may spread at an angle to the stem.
  • In certain species, such as S. flexuosum, branch leaves can markedly alter appearance when dry, spreading, to various degrees, away from the branch.
In addition to most of the characteristics outlined above Sphagnum flexuosum also has the following characteristics;

  • S. flexuosum is almost always completely green, never flecked reddish, but may occasionally have an yellow tinge.
  • Stem is pale green never flecked reddish.
  • Stem leaves are triangular or tongue shaped, closely appressed to the stem, widely separated and point down and away from the capitulum.
  • Stem leaves are rounded, sometimes slightly hooded, at the apex and more or less fringed at the apex also which helps distinguish it from S. fallax and S. flexuosum.
  • Stem leaves are to 1.2mm in length.
  • Pendent branches are shorter than or the same length as the spreading branches and are usually much paler, nearly white-green, and very closely appressed to the stem, almost concealing it.
  • Spreading branches never tinged red or pink towards the branch base.
  • Branch leaves are ovate and if 5 ranked only very weakly so.

  • Branch leaves are longer than wide but not as dramatically as in S. cuspidatum where they can be about 5 times as long as wide.

  • S. flexuosum may grow to 1.5cm in diameter including fascicles.
  • In S. flexuosum branch leaves stand away from the branch, and become slightly wavy at the edges, when dry. If recurved when dry, only ever slighlty so.
  • Capitulum is well defined, convex and usually stellate i.e. 'star' shaped. When stellate, developing branches between 'rays of the star' are seen in pairs (only 1 or none visible in S. cuspidatum).
  • Well grown shoots to 20cm long.
  • Capsules not recorded in Ireland or Britain.

Sources: Atherton, I., Bosanquet, S., Lawley, M.,  2010; Lockhart, N., Hodgetts, N. & Holyoak, D. 2012a; Smith, A.J.E. 2004.



Habitat

Sphagnum flexuosum is unlikely to be found in some of the more acidic habitats that S. fallax may be recorded from.

Habitats may include but are not necessarily limited to;

  • Transition mire and quaking bog (PF3)
  • Wet grassland (GS4)
  • Riparian woodland (WN5)
  • Wet willow-alder-ash woodland (WN6)
  • Freshwater marsh (GM1)
  • Rich fen and flush (PF1) - flushes more than fen.
  • Wet heath (HH3)

Sources: Atherton, I., Bosanquet, S., Lawley, M.,  2010; Rodwell, J.S. (ed.) 1991; Hill, M.O. et al 1992; Smith, A.J.E. 2004; 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 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

In Rare and Threatened Bryophytes of Ireland identified threats to this species include;

  • Land use change
  • Eutrophication
  • Pollution
Source: Lockhart, N. et al 2012a.

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 2013.

In Rare and Threatened Bryophytes of Ireland the suggested conservation actions is;

  • Research into population size, distribution and trends.
Source: Lockhart, N. et al 2012a.

Distribution

World distribution(GBIF)

Most European records from Sweden and Norway, Ireland and Britain, the Netherlands and Germany.  Records from Finland, central Europe and northern Iberia as well as Iceland. Records from North America mainly on the eastern seaboard. Records also from Japan.

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

What few records there are come from are mostly from the western half of the country. The species is likely under-recorded.

Temporal change

Records submitted to Data Centre in 2025

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 flexuosum 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., 1992. Sphagnum: A Field Guide, Revised by Hodgetts, N.G. & Payne, A.G., ISBN 1 87370 114 4

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 11 December 2014.

Additional comments

Sphagnum fallax is one of three species, the other two being S. angustifolium and S. flexuosum, that were previously considered a single species (S. recurvum). They have the potential to be quite difficult to separate in the field, indeed 'fallax' means 'deceptive' or 'fallacious'. However if attention is paid to the shape of stem leaves, the degree of recurvation of leaves when dry,  the relative length of pendent and spreading branch leaves, as well as colouration it should be possible.

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