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

1. 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.

2. Spores

   Smooth, cylindrical to narrowly elliptical, often slightly allantoid, 5.5-8 x 2-3µm; amyloid; hyaline.

3. Spore Print

   White or very pale brown.

4. Odor and Taste

   No noticeable odor; tough, tasteless and inedible.

5. Habitat & Ecological Role

   On dead hardwood trees and fallen branches, usually beech.

6. Season

   This bracket fungus can be seen all through the year; it sheds spores in late summer and autumn.

Look-Alikes

1. Stereum hirsutum

   The pore surface does not bruise.

2. Trametes versicolor

   Visible white pores.

3. Stereum ostrea

   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

1. Stereum arcticum

2. Stereum insignitum

3. 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)