Upper side view of Stereum bracket.

Genus Stereum Hill ex Pers.

[false turkey-tail and relatives]

Summary: Various species of Stereum were described over many years. Unfortunately, as with some other groups, there was a period of lumping species concepts together. DNA analysis and more careful morphological study has shown that some older species concepts are valid. Species groups require more study. We have three Midwest species that were referred to as S. ostrea in field guides. The S. hirsutum - S. complicatum group needs careful analysis with more specimens from across North America.

Taxon Comparisons

  1. Stereum fasciatum (Schwein.) Fr. 1838

    This non-staining species has medium to large caps. Shape is variable including semicircular (dimidiate) to funnel-shaped and uplifted. The surface has a coarse tomentum, with individual tufts, hairs projecting. Surface hairs rarely wear off in zones to reveal the cap surface. Cuticle (surface under the hairs) turns from brown to black in age. The underside color is grayish tan (beige; café au lait) or warm buff; margin is paler (cream). There is no staining. Otherwise, the underside colors are more similar to S. subtomentosum rather than S. lobatum. Hymenium has both pseudoacanthophyses and lanceolate paraphyses. Grows on hardwoods. It is found in North America and Eastern Asia. See Demoulin (1985) for the differences from S. subtomentosum and S. lobatum; all three occur in the Chicago Region and northern USA; view cap surface with a hand lens or dissecting microscope.

    Stereum fasciatum, PRL 10810, Illinois.
    Stereum fasciatum, Illinois
    Stereum fasciatum, PRL 11824, Illinois.
    Stereum fasciatum, Illinois
  2. Stereum lobatum (Kunze ex Fr.) Fr. 1838

    yellow drop. This medium to large species is zonate, fairly flat, often with narrowed base (spathulate). Varies from noticeably petaloid to effused-reflexed. The margin can be lobed. The first key character is the surface has a very short tomentum, without individual tufts (felted appearance; inrolled hairs that don't stick out). Second key character is the gray hairs wear off in wider, more pronounced, bands to reveal the brown cap layer underneath (naked zones). The underside color is pale ochraceous with a yellow tint. It stains (bleeds) yellow when bruised or rubbed. Hymenium has pseudoacanthophyses. Grows on hardwoods. This is a pantropical species that extends north into eastern North America.

    Stereum, PRL 13611, Illinois.
    Stereum lobatum, Illinois
  3. Stereum subtomentosum Pouzar 1964

    yellow drop. This has similarities and differences with the two preceding species. The medium sized caps (to 5 cm wide) are semicircular, shell-like (dimidiate) or fan-shaped to spathulate, with a narrowed base or a wider attachment; lobed and undulate (not flat), margin can be curved down (involute, often when dried). Adjacent cap edges can fuse or overlap. Surface zonate and densely tomentose (wooly), hairs projecting; young caps can have fasciculate hairs (in bundles). The concentric zones sometimes a bit more ridged. Color is whitish to pale yellowish brown (ochraceous) to grayish. The gray hairs can wear off in narrow bands to reveal the brown cap layer underneath; this is much reduced compared to S. lobatum. Underside color is grayish tan (beige; café au lait) to pale cream, with a slight yellow or orange tint; margin can be paler. Typically stains yellow when bruised or rubbed. Hymenium has lanceolate paraphyses; but pseudoacanthophyses are absent. Grows on hardwoods. Found circumglobal in the north temperate zone (north into Canada). Pouzar (1964) notes a host preference for alder (Alnus), but it also grows on beech (Fagus), birch (Betula), blue beech (Carpinus), and maple (Acer).

    Stereum subtomentosum, 2023 Sep 16, Illinois.
    Stereum subtomentosum, Illinois
    Stereum subtomentosum, 2023 Sep 30, Illinois.
    Stereum subtomentosum, Illinois
    Stereum, PRL 12722, Illinois.
    Stereum subtomentosum?, Illinois
  4. Stereum complicatum (Fr.) Fr. 1838

    This has small ochre (orange) effused discs that fuse together and form reflexed caps, upper surface with short hairs. No staining. Grows on hardwoods. Our most common species in Chicago Region. Was lumped by some into S. hirsutum.

    Stereum complicatum, PRL 11479, Illinois.
    Stereum complicatum, Illinois
  5. Stereum hirsutum (Willd.) Pers. 1800

    Growth is effused-reflexed to resupinate. The upper surface is hirsute to strigose-hirsute (coarse erect hairs). The underside color is egg yolk yellow to orange-yellow. There are various opinions on whether the underside is bright orange or paler; this depends on the taxon concept. The taxon in the strict sense has no staining. Grows on hardwoods. Further DNA analysis is needed to sort out the hirsutum taxon in eastern North America, the one in western North America, and their relations to the S. hirsutum of Europe and Asia.

    Stereum, PRL 13814, Illinois.
    Stereum hirsutum?, Illinois
    Stereum hirsutum, Benjamin Dion, Mushroom Observer 269051, California
    Stereum hirsutum, California
  6. Stereum gausapatum (Fr.) Fr. 1874

    Red drop. Caps are folded, effused-reflexed, often crowded. Underside stains red when fresh. I tend to see it in dense ruffled clusters. Grows on hardwoods, primarily oak (Quercus). The hairy caps with brown zones can be confused with the S. ostrea group, such as S. lobatum, but growth on oak and the red-staining identify it.

    Stereum gausapatum, PRL 12814, Quercus, Illinois.
    Stereum gausapatum, Illinois
  7. Stereum rugosum Pers. 1794

    Red drop. This is a perennial species with multiple layers in cross-section and fairly hard texture. Growth is resupinate to effused-reflexed. The narrow reflexed cap is grayish becoming blackish. Underside is pale ochre to buff, bleeding red (then blackish brown). Found on a variety of hardwoods in its range, often on hazel (Corylus), birch (Betula), and alder (Alnus). Rare on conifers. Circumboreal. Ryvarden (2010) says "Widespread and common in Canada and the eastern United States. How south it is distributed on the continent is unknown to me."

    Stereum rugosum, Paul Cook, iNaturalist 37346976, England.
    Stereum rugosum, England
  8. Stereum sanguinolentum (Alb. & Schwein.) Fr. 1838

    Red drop. Conifer tree. The red-staining and growth on conifers separates this species. The annual growth is effused-reflexed to mostly resupinate. Circumboreal. Compare to S. rugosum that is rarely on conifers.

    Stereum sanguinolentum, PRL MF12136, dead white pine, Wisconsin.
    Stereum sanguinolentum, Wisconsin
  9. Stereum striatum (Fr.) Fr. 1838

    Caps are small with poorly developed upper surface (cutis absent) that is shiny and silky-striate. Underside is pale to grayish-orange. No staining. Grows on hardwoods, favors blue beech (Carpinus). Rare or overlooked in Chicago region because of host limitation.

    Stereum striatum, PRL 13914, Carpinus, Illinois.
    Stereum striatum, Illinois
  10. Stereum ochraceoflavum (Schwein.) Sacc. 1888

    Caps are small, thin, cup-shaped to effused-reflexed; (cutis mostly absent). Surface finely tomentose to hirsute (erect hairs). Underside pale orange to grayish-orange, can have a pinkish tint. No staining. Grows on hardwoods. Widespread in warm temperate and tropical areas. Seems rare here. Known records for Chicago are from 1909 and 1928.

    Stereum ochraceoflavum, Jennifer Rycenga, iNaturalist 20882933, California.
    Stereum ochraceoflavum, California

Taxon Information

This page is my attempt to summarize what is known on Stereum for the northern contiguous United States and also applies to adjacent parts of Canada. There are a dozen or more species depending on their segregation with morphology or DNA analysis. The majority of these can be found in the Midwest and seven are recorded for the Chicago Region. A few additional species are in southern states, with some subtropical species found on the Gulf Coast and in Mexico. See further notes below.

Stereum often have zonate caps. Colors fade at end of season and staining reactions are less reliable (try rubbing water on the underside). The green color of bracket fungi is from algae living on the hairy upperside. All of the Midwest species are on hardwoods except one: the red-staining S. sanguinolentum is found on conifers. Surface features and color staining are more reliable than cap shapes.

The first three species are very similar and were lumped into the S. ostrea group. They are not always as clearly different as the sample photos shown here. A hand lens or dissecting microscope is useful for looking at surface hairs. For more image examples see Delong-Duhon link below.

Species of Northern USA and Canada

These are the species treated here and found in the Upper Midwest. They of course occur elsewhere as well.

  • Stereum complicatum
  • Stereum fasciatum
  • Stereum gausapatum
  • Stereum hirsutum
  • Stereum lobatum
  • Stereum ochraceoflavum
  • Stereum rugosum
  • Stereum sanguinolentum
  • Stereum striatum
  • Stereum subtomentosum

Additional Species, southern USA

This list has additional species described for the southern USA.

  • Stereum australe Lloyd 1913 of Florida, Gulf Coast states, Africa, is similar to S. lobatum but has a grayish-lilac underside that stains red.
  • Stereum styracifluum (Schwein.) Fr. 1838 grows on Liquidambar (sweet gum) and Carpinus (blue beech) from Texas and Alabama to North Carolina and Pennsylvania.
  • Stereum sulphuratum Berk. & Ravenel 1868 has been confused with the Stereum hirsutum group but is now known as Borostereum sulphuratum (Berk. & Ravenel) G.Y. Zheng & Z.S. Bi 1990. It is found from South Carolina to Venezuela.
  • Stereum versicolor (Sw.) Fr. 1838 is a tropical species. Burt (1920): S. versicolor was formerly confused with S. fasciatum, especially in American literature; it is doubtful whether S. versicolor occurs in the United States except very rarely in Florida.

Older Names

This list has older names that were used (mainly those for Chicago Region, such as by Moffatt 1909), with their recent and current status. Stereum was a segregate genus from Thelephora and then itself split into other genera (to other families and orders).

  • Stereum acerinum = Dendrothele acerina.
  • Stereum curtisii = Hymenochaete curtisii.
  • Stereum fasciatum = was a synonym of Stereum ostrea; now distinct.
  • Stereum frustulosum = Xylobolus frustulatus.
  • Stereum gausapatum = current name (Moffat does not mention staining; but see S. spadiceum below).
  • Stereum lobatum = was a form of Stereum ostrea; now distinct.
  • Stereum ochraceo-flavum = current name (but without hyphen).
  • Stereum purpureum = Chondrostereum purpureum.
  • Stereum rameale (Pers.) Burt 1920 nom. illegit. = Stereum ochraceoflavum or Stereum complicatum? ; Not Stereum rameale (Berk.) Massee 1890 = Septobasidium rameale.
  • Stereum rufum = Peniophora rufa.
  • Stereum sericeum = synonym of Stereum striatum (or Stereum ochraceoflavum); for example missapplied to Stereum complicatum.
  • Stereum spadiceum Fr. (with staining) = Thelephora spadicea Fr. 1828 nom. illegit. = Stereum gausapatum; Not Thelephora spadicea Persoon 1801 = now Porostereum spadiceum [Not in N. America].

Taxon Details and Links


  • Stereum Hill ex Pers., Neues Magazin für die Botanik 1: 110 (1794).
  • Thelephora hirsuta Willd., Florae Berolinensis Prodromus: 397 (1787).


I continue to research the literature on Stereum hoping to discern the correct names to apply to the kinds we find in the Upper Midwest. There is a loose consensus among American authors on concepts for a set of names but some treatments of the genus are in disagreement, notably the recent book by Ryvarden (2010). Ryvarden uses S. atrorubrum (a poorly known taxon from British Columbia that should be sequenced) instead of S. subtomentosum; he includes S. ochraceoflavum but does not mention S. complicatum. In some aspects the synonymy of Ryvarden (2010) agrees with parts of Burt (1920).

The majority of our Stereum were described two centuries ago from 1787 to 1832. Then Stereum insignitum was published by Quélet (1890) from Europe. Later, Pouzar (1964) split the circumglobal Stereum subtomentosum from the American Stereum fasciatum. Other authors lumped multiple species under the name Stereum ostrea from 1950's to 1980's. Ryvarden (2010) instead used the name Stereum versicolor (Sw.) Fr. 1838 [basionym: Helvella versicolor Sw. 1788] as it predates his synonyms of S. ostrea, S. fasciatum, S. lobatum, and S. australe. Other names were synonymized in the S. hirsutum group. When taxa are combined then the morphological concept becomes more variable. Demoulin (1985) was one of the authors that began the reverse process of arguing for the separation of taxa based on morphology and distribution. This work continues today with the addition of molecular tools. In the Upper Midwest these segregate species include S. fasciatum, Stereum lobatum, and S. subtomentosum.

Stereum spectabile Klotzsch (1843), of Asia, was moved to Xylobolus spectabilis by Boidin (1958). But now DNA phylogenies show it part of the Stereum clade.

Description links

  1. Pacific Northwest Key Council: Key to STEREUM in the Pacific Northwest.
  2. Sarah DeLong-Duhon, University of Iowa, on iNaturalist: Stereum research; Stereum Project.

Related links

  1. Burt, E.A. 1920. The Thelephoraceae of North America. XII. Stereum. Annals of the Missouri Botanical Garden 7: 81-249. [Get PDF (paginated) or read online at JStor.org. Alternate paginated version online at BiodiversityLibrary.org.]
  2. Delong-Duhon, Sarah G., and Robin K. Bagley. 2020 preprint. Phylogeny, morphology, and ecology resurrect previously synonymized species of North American Stereum. bioRxiv preprint; Posted October 16, 2020. doi: 10.1101/2020.10.16.342840
  3. Demoulin, V. 1985. Stereum fasciatum (Schw.) Fr. and S. lobatum (Kunze:Fr.) Fr.: Two Distinct Species. Mycotaxon 23: 207-217. [Download Mycotaxon pages on cybertruffle.org.uk : 23 p.207.]
  4. Moffatt, W. S. 1909. The Higher Fungi of the Chicago Region: Part I, The Hymenomycetes. Natural History Survey, Bulletin No. VII, Part I. Chicago Academy of Sciences. 156 pp., 24 plates. DOI: 10.5962/bhl.title.3605 [Read Part 1 online at Biodiversity Library; Stereum begins on page 134.]
  5. Pouzar, Z. 1964. Stereum subtomentosum sp. nov. and its taxonomic relations. Česká Mykologie 18(3): 147-156. [In Czech with English Abstract and Summary. PDF of Issue CM-18-3.]
  6. Ryvarden, Leif. 2010. Stereoid fungi of America. Synopsis Fungorum 28. [sold by NHBS.com.]
  7. Ryvarden L. 2020. The genus Stereum - a synopsis. Synopsis Fungorum 40 : 46-96 [Not seen by me. Not yet in print?]
  8. Find other Stereum papers by Kotlaba, Pouzar: search Czech Mycology.

Taxon links for 18596 Stereum

Cite this page as: Leacock, P.R. (2023 Oct 29). Stereum - MycoGuide. Retrieved from https://www.mycoguide.com/guide/fungi/basi/agar/russ/ster/ster

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