Stereum subtomentosum
Description
Stereum subtomentosum is an inedible small to medium bracket fungus. Tough but flexible. Individually small but occurring usually in very busy clusters of overlapping tiers of brackets. The upper surface is sometimes hairy and concentrically zoned with whites, greys, greens, browns, and beiges. The pore surface is smooth and pale and bruises yellow when bruised or scratched with a blade. Varied appearance and morphology.
Common names: Yellowing Curtain Crust.
Mushroom Identification
Fruit Body
Individual fan-shaped brackets are 3 to 7 cm across and have irregularly wavy edges. The colors, which are zoned, are various shades of grayish-orange or grayish yellow. There is no stem, but the attachment region is usually quite narrow. The lower spore-bearing surface is smooth, without pores, and rather paler than the upper surface; it is less distinctly zoned and when bruised bleeds yellow. The flesh is 1 to 2mm thick.
Spores
Smooth, cylindrical to narrowly elliptical, often slightly allantoid, 5.5-8 x 2-3µm; amyloid; hyaline.
Spore Print
White or very pale brown.
Odor and Taste
No noticeable odor; tough, tasteless and inedible.
Habitat & Ecological Role
On dead hardwood trees and fallen branches, usually beech.
Season
This bracket fungus can be seen all through the year; it sheds spores in late summer and autumn.
Look-Alikes
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The pore surface does not bruise.
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Visible white pores.
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Has lighter fruiting bodies.
History
This fungus was described as a unique species in 1964 and given its current scientific name Stereum subtomentosum by the Czeck mycologist and polypores specialist Zdeněk Pouzar (b. 1932). Before this it had been treated as a subspecies of other Stereum fungi - for example in 1874 Elias Magnus Fries referred to it as Stereum ochroleucum subsp. arcticum, which is now treated as a valid synonym of Stereum subtomentosum.
Stereum, the generic name, means tough, and crust fungi in this genus certainly can be difficult to tear when you want to take a small sample for investigation. If you scratch the surface of this fungus it will turn yellow - hence the common name Yellowing Curtain Crust.
The specific epithet subtomentosum comes from sub- meaning less than (in the sense of only slightly) and -tomentosum, meaning hairy or downy.
Synonyms
Stereum arcticum
Stereum insignitum
Stereum ochroleucum
Photo sources:
Photo 1 - Author: Alexis (CC BY-SA 4.0)
Photo 2 - Author: Jerzy Opioła (CC BY-SA 3.0)
Photo 3 - Author: Alexis (CC BY-SA 4.0)
Photo 4 - Author: AJC1 from UK (CC BY-SA 2.0)
Photo 5 - Author: Henk Monster (CC BY 3.0)