• Proposed
  • Under Assessment
  • Preliminary Assessed
  • NTAssessed
  • Published

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
Proposed by
Eugene Popov
Eugene Popov, Tatyana Svetasheva
Comments etc.
Anders Dahlberg, Tsutomu Hattori

Assessment Notes

R-L categories correct, but text here does not match final assessment. Developed and updated version published at IUCN´s Red List update July 18th 2019.


Ascoclavulina sakaii is a wood-inhabiting fungus endemic to temperate East Asia. It form well noticeable irregularly lobed grayish green to olivaceous brown fruiting bodies in massive clusters on dead rotten trunks of broadleaved trees, mostly on Fagus. Though it is rather common in temperate broad leaved forests in Japan (there are at least 34 known localities), and besides it’s known in Russian Far East (1 locality), the total area of distribution is obviously small on a global scale.
Preliminary assessment: it is 34 localities, the total population is estimated approx. 350 localities what correlates with 3500 (max. 7000) mature individuals. It’s supposed that unknown sites could be found in Russia (since in Japan thorough research have been already done). Given ongoing intensive timber harvesting in Far East it’s possible to use C1 criterion with category NT (< 10 000
mature ind. and 5 %  of estimated continuing decline on 10 yr or 3 generations)

Taxonomic notes

The type collection was made in 1973 at Gohougi, Sakaimura, Shimominauchi-gun, Nagano Prefecture, Japan. The fungus has a unique morphology for ascomycete, which makes it easily recognizable in the field. The phylogenetic relationships of Ascoclavulina sakaii whitin Helotiales remain unclear.

Why suggested for a Global Red List Assessment?


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, Popov, 2008), which is the northernmost (ca. 43° N) known today for the species.

Population and Trends

There are at least 35 known local populations. As the fruitings on exposed wood are rather large and easily recognazible, it seems unlikely that the species is overlooked when found. The total area of local populations in Japan is about 25000-30000 km2,  in Russia only one locality is known.
Current trend in Japan is probably rather stable, in Russia uncertain, however intensive timber harvesting in Far East (Teplyakov, 2011; Illegal logging…, 2013; Feditchkina, Lankin, 2016; number of online resource) leads to declining of suitable habitats. According criterium C2 a(i) a status can be considered as Near Threatened.

Population Trend: Uncertain

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.

Temperate Forest


Decline of old growth broadleaf forests area due to logging, wood harvesting, and fires

Housing & urban areasUnintentional effects: subsistence/small scale (species being assessed is not the target) [harvest]Unintentional effects: large scale (species being assessed is not the target) [harvest]Trend Unknown/UnrecordedOther ecosystem modificationsHabitat shifting & alteration

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 many of localities i.e. old growth beech forests in Japan are now well reserved.  Regionally protected in Echime Prefecture (2 VU).  The only known locality of the species in Russia is also under protection as it is whithin the limits of the State Nature Reserve “Kedrovaya Pad”.

Resource & habitat protection

Research needed

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

Population size, distribution & trendsLife history & ecology

Use and Trade



Hattori, T. (2005). Diversity of wood-inhabiting polypores in temperate forest with different vegetation types in Japan. Fungal Diversity 18: 73-88.
Hosoya, T., Hosaka, K., Nam, K.-O. (2018) A check list of non-lichenised fungi occurring on Fagus crenata, a tree endemic to Japan, Mycology, 9:1, 29-34, DOI: 10.1080/21501203.2017.1363092
Hukusima T., Matsui T., Nishio T., Pignatti S., Liang Y., Lu S.-Y., Kim M.-H., Yoshikawa M., Honma H., Wang Y. Phytosociology of the beech (Fagus) forests in East Asia / ed. F. Pedrotti. Berlin, Heidelberg: Springer, 2013. 257 p. (Geobotany Studies: Basics, Methods and Case Studies). doi: 10.1007/978-3-642-35620-9.
Ichihara, Y., Nishiya-Ichihara, Y., Masuya, H., & Kubono, T. (2009). The effect of constructing a road in a natural beech forest on the population of Fagus crenata and variety of fungal flora. Bulletin of the Forestry and Forest Products Research Institute, Ibaraki, (412), 179-185.
Irisawa A. (2016). Hōshasei Cs no kinoko e no torikomi kikō to kankyō-chū de no dōtai no kenkyū. PhD Thesis. Tohoku University [in Japanese].
Kigawa S., Mimura H., Inoue S., Fujisawa T. Macrofungi Flora of Tanzawa Mountains // Tanzawa Oyama Comprehensive Survey Academic Report, 2007. P. 363-368.
Kolbek J., Srutek M., Box E. O. Forest Vegetation of Northeast Asia / ed. M. J. A. Werger. Dordrecht: Springer Science & Business Media, 2013 Vol. 28. 462 p. (Geobotany 28). doi: 10.1007/978-94-017-0143-3.
Morozova, O. V., Popov, E. S. (2008). Mycotheca Petropolitana: series exsiccatorum ab Instituto botanico nomine V.L. Komarovii edita. Fasc. III–V. Nos. 41-100. St Petersburg: Komarov Botanical Institute.
Okino T., Kobayashi S. List of species of Higher Fungi // Checklist of the Wild Animals, Fungi, and Plants of Matsuyama City / eds. K. Ishikawa and H. Matsui. Matsuyama City: Department of Environment, 2012. P. 289-404.
Okuda, T., Yanagisawa, M., Fujimori, F., Nishizuka, Y., Takehana, Y., & Sugiyama, M. (1995). New isolation methods and polymerase chain reaction strain discrimination techniques for natural products screening programs. Canadian journal of botany, 73(S1), 946-954.
Otani, Y. (1974) Ascoclavulina, a new genus of Discomycetes. Transactions of the Mycological Society of Japan 15(1): 1-6.

Teplyakov Victor K.  (2011) Current trends in the Russian Far East forest sector, Forest Science and Technology, 7:3, 103-109, DOI: 10.1080/21580103.2011.594603
Illegal logging in the Russian Far East: global demand and taiga destruction. Smirnov, D.Y. (ed.) Kabanets, A.G., Milakovsky, B.J., Lepeshkin, E.A., Sychikov, D.V. 2013. WWF,vMoscow. 39 p.v https://wwf.ru/en/resources/publications/booklets/illegal-logging-in-the-russian-far-east/
Feditchkina Tracy E. ,  Lankin A. Analysis of Timber Exports from the Russian Far East in 2015.  — Vladivostok: WWF-Russia, 2016. — 44 p. https://wwf.ru/upload/iblock/b50/analysis_of_timber_far_east_eng.pdf

Online resources on distribution:
“Red List of Threatened Fungi of Japan”, Biodiversity Center of Japan, accessed on November 5, 2013, http://www.biodic.go.jp/english/rdb/red_fungi.csv

Online resource on a topic of illegal logging in Siberia and Far East (an unprecedented rate):
In Russia’s Vast Far East, Timber Thieves Thrivehttps://www.npr.org/sections/parallels/2013/10/22/239665474/in-russias-vast-far-east-timber-theives-thrive
The Bugbear of Chinese Deforestation: The Real Threat to Russia’s Forests https://carnegie.ru/commentary/77200
Russia Is Running Out of Forest https://www.themoscowtimes.com/2014/09/30/russia-is-running-out-of-forest-a39951
Illegal Logging in the Russian Far East: Global Demand and Taiga Destruction https://www.worldwildlife.org/publications/illegal-logging-in-the-russian-far-east-global-demand-and-taiga-destruction
Illegal Logging of Russian Forests Threatening Tiger Habitat and Supplying Products Destined for US and Europe – WWF http://www.worldwildlife.org/press-releases/illegal-logging-of-russian-forests-threatening-tiger-habitat-and-supplying-products-destined-for-us-and-europe-wwf
Influence of logging on the effects of wildfire in Siberia https://iopscience.iop.org/article/10.1088/1748-9326/8/4/045034/meta
Deforestation of Siberian forests (In Russian - Вырубка сибирских лесов)  https://www.youtube.com/watch?v=xIBceep0oXc
Forest cutting in Siberia (In Russian -Вырубка леса в Сибири) https://www.youtube.com/watch?v=IloOgweXKo0

Known distribution - countries

Regional Population and Trends

Country Trend Redlisted