Petalophyllum ralfsii | Petalwort



Conservation status

Future Prospects
Overall Assessment of Conservation Status
Overall Trend in Conservation Status
Source: NPWS 2013.

IUCN Conservation Status
Ireland (1)
Least concern
Europe (2)
Not evaluated*
Global (2)
Not evaluated

*Although not published separately, an evaluation of 'Vulnerable' 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 2014.2

Legal status

Protected by the following legal instruments:

  • Habitats Directive [92/42/EEC] Annex II
  • Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention) Appendix I
  • Wildlife Act (1976)
  • Flora Protection Order 1999
  • Wildlife (Amendment) Act (2000). 
  • The Wildlife (N.I.) Order 1985 (as amended).

Native status


Species Biology


Thalloid liverwort which grows in a rosette that is usually under 1.5 cm diameter. The thallus has many upright, parallel lamellae which are thin (1 cell) and leaflike and spread across thallus from the mid-rib out, giving an overall appearance of a miniature lettuce. Very distinctive but can be confused with Fossombronia spp.however most of those have distinctive purple rhizoids, those of Petalophyllum ralfsii are pale brown or colourless.

Source: Lockhart, N., Hodgetts, N. & Holyoak, D. 2012a.

Preferred environment


Habitats include but are not necessarily limited to;

  • Dune slacks (CD5)
  • Machair (CD6)

Petalwort appears to be more suited to damp rather than permanently wet ground. More likely to be found on bare ground or in very short grass in base rich, calcareous situations. Mostly, but not exclusively, coastal.

Sources: Lockhart, N., Hodgetts, N. & Holyoak, D. 2012a; Paton, Jean A. 1999.

Life stages


Sporophytes produced March to June.

Source:Paton, Jean A. 1999

Threats faced

In the Article 17 Habitats Directive reporting for the period 2007-2012 there are no threats or pressures identified.

It is noted in the assessment that undergrazing of sites can lead to the species being out-competed, however this undergrazing is a localised occurence.

Source:NPWS (2013).

It is noted in 'Rare and Threatened Bryophytes of Ireland' that due to the habitat where it is primarily found there is are potential threats which include;

  • Holiday developments [buildings / caravan parks]
  • Recreational activities
  • Removal of turf
  • Undergrazing
  • Water abstraction
Source: Lockhart, N., Hodgetts, N. & Holyoak, D. 2012a.

Conservation actions

In the Article 17 Habitats Directive reporting for the period 2007-2012 Conservation Measures in place or being implemented during the period were

  • Continued legal protection of the species and its habitats inside and outside of Natura 2000 sites.

Source: NPWS 2013.

In 'Rare and Threatened Bryophytes of Ireland' it was noted that, from a global perspective, Ireland appears to have an substantial number of populations with substantial total numbers within some of those populations. Although the species is considered, from an IUCN Red List perspective, Least Concern on a national basis, as the European assessment is Vulnerable the Irish populations may be considered as of Conservation Concern. In order to conserve the Irish populations it is suggested that;

  • Sand Dunes and Machair be protected from disturbance and development
  • Petalophyllum ralfsii populations be monitored.

Source: Lockhart, N., Hodgetts, N. & Holyoak, D. 2012a

In the 2012 Irish Red List for Bryophytes the following were suggested as Conservation Actions.

  • Ex-situ Conservation
  • Awareness and Communications

Source: Lockhart, N., Hodgetts, N. & Holyoak, D. 2012


World distribution(GBIF)

Scattered distribution in western Europe, Mediterranean and North Africa. It has also been recorded in North America but this may in fact be a different species.

Source: Lockart N., Hodgetts N., Holyoak D. 2012a

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.

Global distribution mapping for Petalophyllum ralfsii is not currently available via the GBIF mapping service.

Irish distribution

Distribution is generally limited to the west coast of Ireland with a small distribution of the coast of Dublin.

Temporal change

Records submitted to Data Centre in 2023

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 on the distribution of Petalophyllum ralfsii in Ireland. Should you observe the this species, please submit sightings to add to the database. Detailed observations will assist us gaining a better insight into where Petalophyllum ralfsii 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



Fossitt, J.A. (2001) A Guide to Habitats in Ireland. The Heritage Council.

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.

NPWS (2013) The Status of EU Protected Habitats and Species in Ireland.  Species Assessments Volume 3. Version 1.0. Unpublished Report, National Parks & Wildlife Services. Department of Arts, Heritage and the Gaeltacht, Dublin, Ireland.

Paton, Jean A.(1999) The Liverwort Flora of the Bristish Isles. Harley Books.

The IUCN Red List of Threatened Species. Version 2014.2. <>. Downloaded on 26 September 2014.