• Proposed
  • Under Assessment
  • ENPreliminary Assessed
  • 4Assessed
  • 5Published

Hohenbuehelia culmicola Bon

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Scientific name
Hohenbuehelia culmicola
Common names
Marram Oyster
Pleurote des oyats
IUCN Specialist Group
Mushroom, Bracket and Puffball
Assessment status
Preliminary Assessed
Preliminary Category
EN C2a(i)
Proposed by
Begoña Aguirre-Hudson
Martyn Ainsworth
Begoña Aguirre-Hudson, Tommy Knutsson, Thomas Læssøe
Anders Dahlberg

Assessment Notes


European endemic resembling a small oyster mushroom almost always found fruiting at the base of dead Ammophila in coastal sand dunes with most populations recorded around the Atlantic and North Sea coastlines. Recently distinguished from H. bonii which can have larger fruitbodies and can co-occur. Eight countries with records since 1980. and ca. 45 fruiting patches are known. Applying Criterion C, using an estimate of <2,500 mature individuals in total, but less than 250 mature individuals in each subpopulation, and accepting a continuing decline in habitat quality from continued trampling of dunes and their conversion to other uses (golf courses, caravan sites, more permanent housing) produces an assessment of EN C2a(i)

Taxonomic notes

Two marram oyster species (Ainsworth et al. 2016) now recognised as present in France, UK and the Netherlands (this last country added on basis of Flickr report of a redetermination of a “culmicola” collection). When available collections are checked, this could diminish the number of historic records of H. culmicola s.str.

Why suggested for a Global Red List Assessment?

Anders to Martyn: Qualify for EN or VU, no of known mature individuals (45 locations corresponds to 450 mature individuals if max 1 genotype/site). Hoe many times more locations do you estimate is present? Now the estimate is not more than x 5 (if two or more genotypes/site, fewer sites).

Geographic range

Restricted to coastal Ammophila stands particularly around Atlantic and North Sea coasts (one outpost locality in inland dunes in Hungary: Fraiture & Otto (2015) and A. Fraiture in litt.)

Population and Trends

Dahlberg & Croneborg (2003) documented 6 countries with records since 1980 and Spain and Hungary (1 collection) can now be added to this list (Fraiture & Otto (2015) and A. Fraiture in litt.). If pre-1980 records are included, then the range includes Italy and the Republic of Ireland (Dahlberg & Croneborg 2003). Data on fruiting abundance is lacking (numbers of occupied Ammophila plants or ramets), however there are ca. 45 fruiting patches recorded (equivalent to a maximum AOO of ca.180km2). Considered red-listed in around half of the countries of occurence, thought to be extinct in Ireland. Although there is some evidence of habitat decline at some occupied localities, mainly due to changing land usage on coastal dunes and tourist pressures, evidence of a quantified decline is lacking, thus ruling out Criterion A. May possibly qualify for Criterion B since ca. 45 fruiting patches are known to have been recorded (equivalent to a maximum AOO of ca.180km2) but this species is generally not found unless as a result of deliberate and comprehensive sand dune surveys. It is a relatively inconspicuous mushrooms that is likely to have been overlooked due to small size, dark colour and restricted microhabitat. Such survey work has recently been initiated in the Netherlands (E.J.M. Arnolds pers. comm.) and UK (Lost & Found Fungi Project). Therefore there are considerable doubts remaining concerning its true distribution (whether it qualifies for “severely fragmented”) and its population size. Some historic records could be of the recently described species H. bonii which can co-occur with H. culmicola s.str. Criterion C seems most readily appropriate, using an estimate of <2,500 mature individuals in total, but less than 250 mature individuals in each subpopulation, and accepting a continuing decline in habitat quality from continued trampling of dunes and their conversion to other uses (golf courses, caravan sites, more permanent housing).

Population Trend: Decreasing

Habitat and Ecology

Coastal sand dunes, rarely inland dunes growing saprotrophically on Ammophila (possibly also on other Poaceae in same habitat such as Leymus arenarius, which was recorded at one English site). Narrow niche requirements, i.e. dynamic sand dune ecosystems with sparse vegetation of herbs and grasses.

Coastal Sand Dunes


Threats are mainly from conversion of coastal dunes to caravan/camping sites, golf courses or other development and, on a slower timescale, to visitor pressure and recreational disturbance (trampling). Changes in large-scale offshore dredging activities are also suspected to alter coastal dynamics unfavourably for this species, for example by shifting the prevailing deposition from sand to pebbles and shingle accretion (Kent, UK). Storm surges and long-term sea level rise, coupled with the associated coastal management responses, present a clear threat to dynamic dune systems upon which this species depends.
Inland dune systems are under even higher threats of overgrowth, tree plantations and other changes of land use causing changes of edaphic and vegetation structures.

Residential & commercial developmentRecreational activities

Conservation Actions

Further research needed to inform practical conservation action

Site/area protectionResource & habitat protectionHabitat & natural process restoration

Research needed

The main focus of research should be on further systematic survey of suitable habitat and checking of historic collections to determine whether redetermination as H. bonii is required. Surveillance is also important to reveal how its fruiting presence (size and location of occupied grass culms/roots) changes from year to year to assess how ruderal this species is. Population genetics required to estimate the number of genets per plant and to locate the whereabouts of the fungus within the plant (root systems or separate stems). Further ecological research is required to determine whether particular Ammophila-dominated habitats are favoured.

Population size, distribution & trendsLife history & ecologyPopulation trendsHabitat trends

Use and Trade


Ainsworth, A.M., Suz, L.M. & Dentinger, B.T.M. (2016). Hohenbuehelia bonii sp. nov. and H. culmicola: two pearls in the marram oyster. Field Mycology 17(3):78-86

Bon, M. (1970). Flore héliophile des macromycètes de la zone maritime picarde. Thèse de doctorat en Pharmacie (Faculté de Lille). Bull. Soc. Myc. Fr. 86(1): 79–213.

Bon, M. (1980a) [1979]. Taxons nouveaux. Doc. Mycol. 10(37–38): 89–92.

Bon, M. (1980b). Quelques Agaricales “greffees” sur Ammophila arenaria (L.) Link. Doc. Mycol. 11(41):

Bon, M. (1988). Flore mycologique du littoral. Doc. Mycol. 19(74): 62–64.

Buczacki, S. (2012). Collins fungi guide. HarperCollins, London.

Courtecuisse, R. (1985) [1984]. Transect mycologique dunaire sur la Côte d’Opale (France) part 1. Doc. Mycol. 15(57–58): 1–115.

Courtecuisse, R. & Duhem, B. (1995). Mushrooms & Toadstools of Britain & Europe (Collins Field Guide). HarperCollins, London

Dahlberg A & Croneborg H. 2003. 33 threatened fungi in Europe. Complementary and revised information on candidates for listing in Appendix I of the Bern Convention T-PVS (2001) 34 rev 2.

Fraiture, A. & Otto, P. (2015). Distribution, ecology and status of 51 macromycetes in Europe. Meise Botanic Garden.

Fraiture, A. & Walleyn R. (2005). Distributiones fungorum Belgii et Luxemburgi Fasc. 3. Scripta Botanica Belgica 38: 1-79

LAFF (Lost and Found Fungi Project). http://fungi.myspecies.info/content/lost-found-fungi-project

Ludwig, E. (2000). Pilzkompendium Band 1 Abbildungen. IHW Verlag.

Ludwig, E. (2001). Pilzkompendium Band 1 Beschreibungen. IHW Verlag.

Known distribution - countries

Regional Population and Trends

Country Trend Redlisted