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Ascoclavulina sakaii Y. Otani

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Scientific name
Ascoclavulina sakaii
Y. Otani
Common names
クチキトサカタケ (kuchikitosakatake)
аскоклавулина Сакаи
IUCN Specialist Group
Cup-fungi, Truffles and Allies
Assessment status
Assessment date
IUCN Red List Category
Popov, E. & Svetasheva, T.
Iršėnaitė, R. & Mueller, G.M.

Assessment Notes

The content on this page is fetched from The IUCN Red List of Threatened Species: https://www.iucnredlist.org/species/147691134/147691146


Ascoclavulina sakaii is a wood-inhabiting fungus endemic to temperate East Asia, known from Japan and one report from the Russian Federation. It forms easily recognizable irregularly lobed greyish green fruiting bodies in massive clusters on dead rotten trunks of broadleaved trees, mostly Fagus. Though it is widely distributed throughout temperate Fagus dominated forests in Japan (there are at least 34 known localities), and it is known in the Russian Far East (1 locality), the total area of distribution is small on a global scale. The estimated number of localities is 350 with a global population size of approximately 1,400 mature individuals. Therefore, the species is assessed as NT D1.

Taxonomic notes

The type collection was made in 1973 at Gohougi, Sakaimura, Shimominauchi-gun, Nagano Prefecture, Japan.

Geographic range

Ascoclavulina sakaii is endemic to temperate East Asia, currently known from Japan and Russian Far East. In Japan it is widely distributed across Honshu where it was observed from prefectures of Aomori, Iwate, Yamagata, Miyagi, Fukushima, Tochigi, Gunma, Nagano, Ibaraki, Toyama, Shizuoka, Aichi, Nara, Tottori, Hiroshima and Yamaguchi. Also single finds are reported from Shikoku (Echime Prefecture), Kyushu, Dogo Island in Oki archipelago, and from southern part of Hokkaido (Otani 1974, Okuda et al. 1995, Hattori 2005, Ichihara et al. 2009, Irisawa 2016, Hosoya et al. 2018). In Russia, Ascoclavulina sakaii is known from a single location in Primorsky Krai (Morozova and Popov 2008), which is the northernmost (ca 43° N) site known for the species.

Population and Trends

There are 35 known localities, 34 in Japan and one in the Russian Federation. As the fruiting bodies on exposed wood are rather large and easily recognizable, it seems unlikely that the species is overlooked when searched. The total number of localities (including possible unknown ones) is estimated to be approximately 350, which can be equivalent to 1,400 mature individuals (cf. Dahlberg and Mueller 2011).

The current trend in Japan is probably rather stable. In Russia it is uncertain owing to the ongoing intensive timber harvesting in the Far East (Teplyakov 2011, Smimov et al. 2013, Feditchkina and Lankin 2016, Flintoff 2013, Spivak 2018, Eremenko 2014, Conner 2013) leads to declining of suitable habitats.

Population Trend: unknown

Habitat and Ecology

Saprotrophic, growing on decaying wood of broadleaved trees (mainly Fagus). Fruiting bodies develop in summer and autumn, with most observations made in August-September. In Japan it occurs in cool-temperate and temperate broadleaf and mixed forests with Fagus crenata, F. japonica, Quercus serrata, Q. mongolica, Castanea crenata, Acer spp. (orders Quercetalia serratae-grosseserratae and Saso-Fagetalia crenatae of Querco-Fagetea crenatae class). In Russia Ascoclavulina sakaii was reported from cool-temperate mixed forests with Abies holophylla, Pinus koraiensis, Quercus mongolica, Ulmus japonica, Juglans mandshurica, Tilia amurensis, T. mandshurica, Acer spp., Fraxinus mandshurica, Betula costata.


The major threats are decline of old growth broadleaf forests area due to logging, wood harvesting, and fires in the Russian Federation.  The Japanese subpopulation is considered stable.

Conservation Actions

Ascoclavulina sakaii was previously included in the Red List of Threatened Fungi of Japan (1997) as Threatened I (CR+EN)), though now it is excluded from the list because most of the localities i.e. old growth beech forests in Japan are well preserved. Regionally protected in Echime Prefecture (2 VU). The only known locality of the species in Russia is also under protection as it is within the limits of the State Nature Reserve “Kedrovaya Pad”.

A search for new localities in Russian Far East as well as clarification of environmental requirements and ecological preferences are needed.

Use and Trade

There is no information on practical use of this species.

Source and Citation

Popov, E. & Svetasheva, T. 2019. Ascoclavulina sakaii. The IUCN Red List of Threatened Species 2019: e.T147691134A147691146. https://dx.doi.org/10.2305/IUCN.UK.2019-2.RLTS.T147691134A147691146.en .Accessed on 2 February 2022

Country occurrence