Stereum rugosum (Pers.) Fr. - Bleeding Broadleaf Crust

Phylum: Basidiomycota - Class: Agaricomycetes - Order: Russulales - Family: Stereaceae

Stereum rugosum  - Bleeding Broadleaf Crust

Distinguished from most other crusts that occur on hardwoods by the characteristic of bleeding and remaining red when it has been scratched, Stereum rugosum is a very common but often overlooked crust fungus.

Distribution

Stereum rugosum is abundant and widespread throughout Britain and Ireland. On mainland Europe this wood-rotting crust fungus is found from Scandinavia right down to the Mediterranean region, and its range extends eastwards into Asia's temperate regions too. In North America this crust fungus is also very common.

Stereum rugosum  - Bleeding Broadleaf Crust, Wales

Taxonomic history

This crust fungus was described in 1801 by Christiaan Hendrik Persoon, who gave it the scientific name Thelephora rugosa.

In 1838 Swedish mycologist Elias Magnus Fries transferred this species to the genus Stereum, and its scientific name, still generally accepted today, became Stereum rugosum.

Synonyms of Stereum rugosum include Thelephora rugosa Pers., Thelephora coryli (Pers.) Pers., Thelephora laurocerasi Berk., and Stereum stratosum Berk. & Broome.

Etymology

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. The specific epithet rugosum refers to the fact that the fertile surface of this crust fungus becomes red (rugose) when scratched.

Identification guide

Fertile surface of Stereum rugosum

Fruitbody

Entirely resupinate when young, sometimes becoming slightly detached at the edges when old; 1 to 3.5 mm thick; fertile surface may be either smooth or somewhat uneven; buff when young but paler at the edges, soon becoming ochre with a pinkish tinge. Old fruitbodies turn grey.

When it is scratched the fertile surface 'bleeds' and turns red.

 

Spores of Stereum rugosum

Spores

Cylindrical, smooth, 7-12 x 3.5-4.5µm; amyloid.

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Spore print

White.

Odour/taste

No noticeable odour; tough, tasteless and inedible.

Habitat & Ecological role

Saprobic, on dead hardwood trees and fallen branches, particularly Hazel.

Season

All through the year, but shedding spores only in autumn.

Similar species

Bleeding Oak Crust Stereum gausapatum is darker and grows mainly on dead trunks and branches of oak trees, Quercus sp.; its spores are somewhat smaller than those of Stereum rugosum.

Stereum subtomentosum has an upper surface that is zoned in various shades of greyish-orange or greyish white; it usually forms reflexed crusts or brackets.

Stereum hirsutum is hairy on its upper surface and often forms reflexed crusts or brackets.

Culinary Notes

Tough and leathery, these tasteless fungi are inedible and of no culinary value.

Reference Sources

Pat O'Reilly (2016). Fascinated by Fungi, First Nature Publishing.

BMS List of English Names for Fungi.

Paul M. Kirk, Paul F. Cannon, David W. Minter and J. A. Stalpers. (2008). Dictionary of the Fungi; CABI.

Taxonomic history and synonym information on these pages is drawn from many sources but in particular from the British Mycological Society's GB Checklist of Fungi and (for basidiomycetes) on Kew's Checklist of the British & Irish Basidiomycota.

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