Public Description of Bondarzewia occidentalis Jia J. Chen, B.K. Cui & Y.C. Dai

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Name: Bondarzewia occidentalis Jia J. Chen, B.K. Cui & Y.C. Dai
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Description status: Unreviewed

Taxonomic Classification:

Domain: Eukarya
Kingdom: Fungi
Phylum: Basidiomycota
Class: Agaricomycetes
Order: Russulales
Family: Bondarzewiaceae

General Description:

Large, fleshy, annual, fall-winter fruiting, stalked terrestrial polypore s.l., near the base of conifers, with a scurfy, yellow-orange to pale purple-brown cap, with latex in cuts of fresh tube layer, and white spores.1 3 5 7

Diagnostic Description:

Morphological Habit: polypore. See Polyporales sensu lato
Cap: fanlike, 5-25 cm wide, typically single to few from one stem, scurfy-finely tomentose, yellow-orange to orange-brown or pale purple-brown.
Pore Surface: white, pores angular, becoming lacerate at the edges, 1-3 mm in diam; 0.5-2.0 pores/mm
Stem: 4-12 cm long and 2-5 cm thick.
Context: cream colored, firm.
Odor: pleasant, nut-like.
Taste: mild, occasionally acrid.
Spores: subglobose, 6-8 × 5-7µm, with short, amyloid, ridges.1 3 5 7 (as B. mesenterica).

This Western North American species previously went under Bondarzewia mesenterica, which is a European species. Chen 9 B. occidentalis differs from B. mesenterica in its range, the lengths of the spines on its spores, the cap color (according to the authors) and its DNA. B. occidentalis is more closely related to the East Asian B. dickinsii than to B. mesenterica.


Pacific Northwest, British Columbia to Northern California.1 3 5 7 9


Late successional conifer forests, at the base of conifers, dead or dying trees or stumps.1 3 5 7 Per Ginns5, especially with Larix (Larch), at higher elevations.
Fruits fall-winter.1 3 5 7

Look Alikes:

Boletopsis smithii has a dull orange stem surface.5

Bondarzewia berkeleyi is limited to eastern North America, is a hardwood associate, and has slightly larger (7-9 × 6-8µm) spores.1 3 5 7

Bondarzewia mesenterica is limited to Europe, and other Bondarzewia spp. have ranges which are different from B. occidentalis.9

Grifola frondosa forms more numerous, smaller and drab grey-brown fronds, 2-6 cm across, while Bondarzewia forms fewer large fronds, 7-12 cm across, in more colorful shades of brown with tinges of purple and orange. G. frondosa has a thinner (1-2mm), shallower pore layer, and smaller, more tightly organized, pores. G. frondosaspores are inamyloid, oval, smooth. 2 5

Meripilus giganteus blackens when bruised along cap edge and on pore surface.3

Phaeolus schweinitzii has brown flesh, green to brown pores; B. occidentalis has white, pallid or at most beige flesh, cream pore surface.3


Eaten by some under the common name “wild maitake”.2
Causes white, stringy root and butt rot.1 5


1 Castellano, Smith, O’Dell, Cázares, Nugent, Susan. 1999. Handbook to strategy 1 fungal taxa from the Northwest Forest Plan. Gen. Tech. Rep. PNW-GTR-476. Portland, OR: USDA Forest Service Pacific Northwest Research Station. 195 p. (as B. mesenterica).

9 Jiajia Chen, Baokai Cui, Shuanghui He, Jerry A. Cooper, Matthew D. Barrett, Junliang Chen, Jie Song & Yucheng Dai (2017) Molecular phylogeny and global diversity of the remarkable genus Bondarzewi (Basidiomycota, Russulales), Mycologia, 108:4, 697-708, DOI: 10.3852/14-216

2 Frank, “Bondarzewia mesenterica in culture, the market and wild”, McIlvainea, Volume 20 (2011) (as B. mesenterica)

3 Gibson, Matchmaker: Mushrooms of the Pacific Northwest, Version 2.2.1 (2015) (application, latest version downloadable at (as B. mesenterica)

4 J. Ginns, Annotated Key to Pacific Northwest POLYPORES (2007) (as B. mesenterica)

5 Ginns, J. 2017, Polypores of British Columbia. Prov. B.C. Tech. Rep. 104. (as B. mesenterica)

6 MycoBank Record MB809901

7 Noah Siegel & Christian Schwarz, Mushrooms of the Redwood Coast (Ten Speed Press 2016) ( (as B. mesenterica)

8 Species Fungorum Record 809901


Frank2 reports seeing this sold as “wild maitake”.

Description author: Django Grootmyers (Request Authorship Credit)
Description editor: Joseph D. Cohen

Created: 2017-02-15 15:30:24 PST (-0800) by Django Grootmyers (heelsplitter)
Last modified: 2018-03-28 16:26:47 PDT (-0700) by Joseph D. Cohen (Joe Cohen)
Viewed: 28 times, last viewed: 2019-09-19 18:14:32 PDT (-0700)