• Proposed
  • Under Assessment
  • 3Preliminary Assessed
  • 4Assessed
  • 5Published

Polyporus subvarius C.J. Yu & Y.C. Dai

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Scientific name
Polyporus subvarius
C.J. Yu & Y.C. Dai
Common names
IUCN Specialist Group
Mushroom, Bracket and Puffball
Assessment status
Under Assessment
Proposed by
Tsutomu Hattori
Tsutomu Hattori
Comments etc.
Anders Dahlberg

Assessment Notes

Russia seems to be the distribution center for this fungus. It is better to be left as DD until population trend in Russia will become clear.

Taxonomic notes

This fungus was first described from China (Tibet). It has been confused with Favolus pseudobetulinus in Japan, but revealed to be distinct by detailed morphological and phylogengetic studies.

Why suggested for a Global Red List Assessment?

Polyporus subvarius was described from China (Tibet), and later reported from a mountainous area in Hokkaido, Japan. Hitherto only known from one locality in China, and 3 localities (around Mt. Taisetsu) in Japan. This species has high host specificity, and all known collections were made on Salix spp. Salix spp. are intolerant, and can be declined by natural succession. Known localities are situated in boreal mountainous areas, and can be influenced by the global warming.

Geographic range

Hitherto known form one area in China (Tibet), and 3 localities around Mt. Daisetsu, Japan.

Population and Trends

Only a single specimen is known from the type locality. 3 localities are known from Japan, only by a single specimen for each locality.

Population Trend: Uncertain

Habitat and Ecology

On living (or dead?) trees of Salix spp. in boreal subalpine areas. White rot fungi.

Boreal Forest


This fungus is specific to Salix sp. in limited areas of East Asian subalpine forest. Decline of the host trees should be a threat for this fungus. Known collection sites in Japan are now reserved.  Salix species are intolerant, and can be decreased by the natural succession. Known localities are situated in boreal mountainous areas, and can be influenced by the global warming.

Climate change & severe weather

Conservation Actions

Conservation of the host trees in the distribution sites is desirable.

Site/area protection

Research needed

This species is confused with Favolus pseudobetulinus, sharing similar ecology and morphology in East Asia. Detailed distribution should be studied for both of the species.

Population size, distribution & trends

Use and Trade


Dai, Y.C; Yu, C.J.; Wang, H.C. 2007. Polypores from eastern Xizang (Tibet), western China. Ann. Bot. Fennici 44:135–145.
Sotome, K; Hattori, T.; Ota, Y. 2011. Taxonomic study on a threatened polypore, Polyporus pseudobetulinus, and a morphologically similar species, P. subvarius.

Country occurrence

Regional Population and Trends

Country Trend Redlisted