Major Groups > Crust Fungi > Phlebiopsis crassa


Phlebiopsis crassa

[ Basidiomycota > Polyporales > Phanerochaetaceae > Phlebiopsis . . . ]

by Michael Kuo

I love this fungus. Phlebiopsis crassa is one of the best things about the fall woods in my area. It is a crust fungus that can be found spreading across sticks and logs in hardwood forests across North America, but unlike many other crusts it is a beautiful shade of purple (at least, when fresh and young). Up close, its surface is fairly smooth, while its paler edges are finely fuzzy and appear to be less firmly attached to the wood.

Under the microscope, Phlebiopsis crassa features amazing cystidia that are quite long and become encrusted with refractive granular material, beginning at the apex of the cystidium, often resulting in a harpoon-like appearance.

Synonyms are numerous and include Porostereum crassum, Phanerochaete crassa, and Lopharia crassa.


Ecology: Saprobic and possibly parasitic on the recently fallen (with bark still adnate) wood of hardwoods; causing a white rot of the heartwood; spreading in solitary or gregarious patches; fall; apparently widely distributed in North America but absent or rare on the West Coast. The illustrated and described collections are from Illinois.

Fruiting Body: Individual patches 3–28 cm across; irregular in outline. Surface bald or very finely velvety when fresh, developing fine cracks with age; purple when fresh, maturing to brownish purple or purplish brown; with a pale purple to whitish, fuzzy marginal zone. Flesh less than 1 mm thick; colored like the surface.

Odor: Not distinctive.

Chemical Reactions: KOH on surface dark gray-brown to black.

Microscopic Features: Spores not found in my collections but reported by Burdsall (1985) as "narrowly ellipsoid, 6–8 x 3–3.5(–4) µm; hyaline, thin-walled, smooth." Hyphal system monomitic; hyphae 5–7.5 µm wide, smooth, hyaline or brownish in KOH, thick-walled, septate. Cystidia abundant; 75–250 x 7.5–12.5 µm; elongated-fusiform to cylindric; walls up to 4 µm thick; golden to brownish golden in KOH; surface becoming granular-encrusted, beginning with the apex; often developing a harpoon-shaped apex. Clamp connections not found.

REFERENCES: (Léveillé, 1844) Floudas & Hibbett, 2015. (Burdsall, 1985; Chamuris, 1988; Floudas & Hibbett, 2015; Miettinen et al., 2016; Woehrel & Light, 2017.) Herb. Kuo 10011201, 10201801.

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Phlebiopsis crassa

Phlebiopsis crassa

Phlebiopsis crassa

Phlebiopsis crassa

Phlebiopsis crassa

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Kuo, M. (2018, December). Phlebiopsis crassa. Retrieved from the MushroomExpert.Com Web site: