• Proposed
  • Under Assessment
  • Preliminary Assessed
  • Assessed
  • ENPublished

Hygrocybe noelokelani Desjardin & Hemmes

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Scientific name
Hygrocybe noelokelani
Desjardin & Hemmes
Common names
IUCN Specialist Group
Mushroom, Bracket and Puffball
Assessment status
IUCN Red List Category
Proposed by
Else Vellinga
Else Vellinga
Anders Dahlberg

Assessment Notes

Therefore it is classified as Endangered under criteria C1.
The total number of mature individuals is estimated not to exceed 2 500, and an estimated decline of the habitat availability of 20% over 20 years, which is based on the spread of the disease that kills Metrosideros polymorpha, which in 3 years has spread from Hilo to an altitude of 1800 m, along the Saddle Road, where three of the four localities of this species occur


Taxonomic notes

The species has fruitbodies that are covered in slime, and have a pink cap, a white stem and white gills; it differs from closely related species known to occur in New Zealand in the pink colours of the pileus. The name ‘noelokelani’ means ‘the pink rose in the mist or rain forest’.
This species probably belongs in the genus Gliophorus, but there are no molecular data to support that, and a formal transfer to that genus has not been made.

Why suggested for a Global Red List Assessment?

Hygrocybe noelokelani is native to Hawaii where it was found in three locations on the Big Island, and one on Kauai. It is restricted to Wet Montane Forests which are dominated by Metrosideros polymorpha (ʻŌhiʻa). This tree species is under immediate threat by ROD, Rapid ʻŌhiʻa Death, a fast spreading disease caused by Ceratocystis fimbriata, so far only restricted to the Big Island of Hawaii. A second threat is the widening of the Saddle Road on the Big Island; this project will destroy several of the kipukas (tree islands amid solidified lava streams) where this species was found.

Considered to be EN ( Endangered) under C1, based on an estimated number of mature individuals less than 2,500, and an estimated decline of the habitat availability of 20% over 20 years, which is based on the spread of the disease that kills Metrosideros polymorpha, which in 3 years has spread from Hilo to an altitude of 1800 m, along the Saddle Road.

Geographic range

Known from a few locations on two islands of the Hawaiian archipelago, the Island of Hawaiʻi and Kauai.

Population and Trends

Very rare, only known from a couple of sites on two small islands in Hawaii in threatened habitats (tree death, and human activities). It has been looked for in the other islands by experienced mycologists who described the species but there are no records from them. It is conspicuous enough and easy to identify as well to be found and identified by amateurs as testified by an award winning essay by a 15-year old (American Museum of Natural History 2002).


Population Trend:

Habitat and Ecology

Solitary to scattered on bare soil, on soil among mosses, or on moss covered stems of hapu’u (Cibotium spp.) in Montane Mesic Forest (Ohi’a Forest) or Montane Wet Forest (Ohi’a/Hapu’u Forest) (Dennis & Desjardin 1997).
Hygrocybe and Gliophorus species are biotrophic (living symbiotically with living plants), but it is not known in which way they interact with the plant and how they get their sugars (Griffith et al. 2002; Halbwachs et al. 2013; Seitzman et al. 2011).

Subtropical/Tropical Moist Montane Forest


Habitat destruction is the biggest threat to the occurrence of this species, first of all because of a rapidly spreading deadly disease of the host tree (Metrosideros polymorpha; ʻŌhiʻa), caused by Ceratocystis fimbriata (Keith et al. 2015; http://www2.ctahr.hawaii.edu/forestry/disease/ohia_wilt.html). Ceratocystis fimbriata kills mature trees and since it was first detected in the Kuna and Hilo Districts on the Big Island in Hawaii, it has spread, reached in 2016 the areas where Hygrocybe noelokelani occurs, and is threatening all habitats in which Metrosideros is the dominant tree. The name of the disease, Rapid ʻŌhiʻa Death, is an indication of its sudden appearance and fast work. This will change the whole ecosystem of the islands, as Metrosideros polymorpha is dominant in many different habitats.
Secondly, habitat destruction of the kipukas, tree islands in the middle of old lava flows, along the Saddle Road on the Big Island because of widening of the road. The Saddle Road connects Hilo with the observatory on Mauna Kea, and is the shortest route from Hilo to the Kona coast.

Roads & railroadsNamed species

Conservation Actions

Sanitary actions to restrict the spread of Ceratocystis fimbriata are already in place (see http://www2.ctahr.hawaii.edu/forestry/disease/ohia_wilt.html), and need to be reinforced.
Secondly, further widening of the Saddle Road has to be done in such a way that the kipukas (the montane tree islands amide the lava flows, the habitats of the native Hawaiian mushroom species) are spared.

Site/area managementInvasive/problematic species controlPolicies and regulations

Research needed

Cause of the infection, spread, identity, life cycle and ecology of Ceratocystis fimbriata have to be further researched.
Ceratocystis-resitant strains of Metrosideros polymorpha have to be developed.

Use and Trade


Dennis, D.E. & D.E. Hemmes, 1997. Agaricales of the Hawaiian Islands. 4: Hygrophoraceae. Mycologia 89: 615–638.
Griffith, G.W., G.L. Easton & A.W. Jones, 2002. Ecology and diversity of waxcap (Hygrocybe spp.) fungi. Botanical Journal of Scotland 54(1), 7–22.
Halbwachs H., P. Karsch & G.W. Griffith, 2013. The diversity of Hygrocybe – peeking into an enigmatic lifestyle. Mycosphere 4: 773–792. Doi 10.5943/mycosphere/4/4/14
Keith, L.M., R.F. Hughes, L.S. Sugiyama, W. P. Heller, B.C. Bushe & J.B. Friday. 2015. First Report of Ceratocystis wilt on ʻŌhiʻa. Plant Disease 99: 1276.http://dx.doi.org/10.1094/PDIS-12-14-1293-PDN
Seitzman BH, Ouimette A, Mixon RL, Hobbie EA, Hibbett DS. 2011 – Conservation of biotrophy in Hygrophoraceae inferred from combined stable isotope and phylogenetic analyses. Mycologia 103(2), 280–290.

Known distribution - countries

Regional Population and Trends

Country Trend Redlisted