Cyphellostereum

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Genus of fungi

title: "Cyphellostereum" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["hygrophoraceae", "agaricales-genera", "lichen-genera", "basidiolichens", "taxa-described-in-1965", "taxa-named-by-derek-reid"] description: "Genus of fungi" topic_path: "general/hygrophoraceae" source: "https://en.wikipedia.org/wiki/Cyphellostereum" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Genus of fungi ::

| image = Cyphellostereum pusiolum 28444179.jpg | image_caption = Cyphellostereum pusiolum | taxon = Cyphellostereum | authority = D.A.Reid (1965) | type_species = Cyphellostereum pusiolum | type_species_authority = (Berk. & M.A.Curtis) D.A.Reid (1965) | subdivision_ranks = Species | subdivision = see text

Cyphellostereum is a genus of basidiolichens. Species produce white, somewhat cup-shaped fruit bodies on a thin film of green on soil which is the thallus. All Cyphellostereum species have nonamyloid spores and tissues, lack clamp connections, and also lack hymenial cystidia.

DNA research has shown that a common, north temperate species formerly known as Cyphellostereum laeve is not related to the type species and belongs in a quite separate order, the Hymenochaetales. It has been renamed Muscinupta laevis.

Etymology

The name Cyphellostereum combines two generic names: Cyphella in reference to the inverted cupulate form (like the genus Cyphella); and Stereum, in reference to the stipitate fan-shape or bracket shape (as in species of Stereum).

Evolution and morphology

Multilocus phylogenetic trees recover Cyphellostereum as a monophyletic, basal branch that is sister to all other genera in the Dictyonema clade. Occupying this early-diverging spot, the genus retains the simplest thallus: a bluish, crust-like weave of cyanobacterial filaments (trichomes) sheathed by the fungus, with no layered or medulla that would distinguish an upper or lower surface. Its reproductive structures are tiny, cup-shaped cyphelloid fruiting bodies (basidiocarps) that sit on the thallus rather than being swallowed by it; the hyphae that build these cups differ markedly from the slender hyphae that merely clothe the threads. The fungal sheath is made of irregular, cylindrical cells full of air-gaps and it entirely lacks the tubular haustoria and "jigsaw-puzzle" cell walls that later genera use to tap nutrients from the cyanobacteria. The cyanobacterial partner (Rhizonema) forms unusually narrow cells (roughly 5–8 μm wide), and specimens often harbour extra cyanobacteria or even stray green algae, signalling a looser, more opportunistic symbiosis than is typical for the group. Comparative studies also show that the Rhizonema photobiont in Cyphellostereum develops trichomes with narrower, higher, roughly quadrate cells that are more distinctly blue than the broader, low-celled forms typical of Dictyonema.

Internal transcribed spacer (ITS) DNA in Cyphellostereum shows the highest length variation and alignment ambiguity within the clade, consistent with an ancient, slowly diverging lineage. Because it preserves this primitive, loosely integrated architecture while its descendants evolve ever more complex, leaf-like thalli, Cyphellostereum offers a living snapshot of the earliest steps toward basidiomycete lichenisation.

Species

::figure[src="https://upload.wikimedia.org/wikipedia/commons/e/e8/Cyphellostereum_bicolor.png" caption="The thallus of ''Cyphellostereum bicolor'' comprises filamentous, bicoloured patches;
scale bar=1 mm"] ::

References

References

  1. (2013). "Starting from scratch: Evolution of the lichen thallus in the basidiolichen ''Dictyonema'' (Agaricales: Hygrophoraceae)". Fungal Biology.
  2. (2017). "High levels of endemism among Galapagos basidiolichens". Fungal Diversity.
  3. (2019). "A first phylogenetic assessment of Dictyonema s.lat. in southeastern North America reveals three new basidiolichens, described in honor of James D. Lawrey". Plant and Fungal Systematics.
  4. (2009). "High concentration of basidiolichens in a single family of agaricoid mushrooms (Basidiomycota: Agaricales: Hygrophoraceae)". Mycological Research.
  5. (2014). "''Dictyonema coppinsii'', a new name for the European species known as ''Dictyonema interruptum'' (Basidiomycota: Agaricales: Hygrophoraceae)". The Lichenologist.
  6. (2016). "New species of ''Dictyonema'' and ''Cyphellostereum'' (lichenized Basidiomycota: Hygrophoraceae) from tropical Africa and the Indian Ocean, dedicated to the late Hildur Krog". Willdenowia.
  7. Marcano, Vicente. (2022). "Eight new species of lichenized Basidiomycota in the genera ''Acantholichen'', ''Cyphellostereum'' and ''Dictyonema'' s.str. (Agaricales, Hygrophoraceae) from northern South America". Phytotaxa.
  8. (2022). "''Cyphellostereum ushima'' sp. nov. (Hygrophoraceae, Agaricales) described from Amami-Oshima Island (Kagoshima Prefecture, Ryukyu Islands), Japan, with ultrastructural observations of its ''Rhizonema'' photobiont filaments penetrated longitudinally by a central haustorium". Mycological Progress.
  9. "''Cyphellostereum indicum'' (Hygrophoraceae), a new species of basidiolichen from India". Phytotaxa.
  10. Reid, D.A.. (1965). "A monograph of the stipitate stereoid fungi". Beihefte zur Nova Hedwigia.
  11. Ryvarden, Leif. (2010). "Stereoid fungi of America". Fungiflora.
  12. (2011). "A first assessment of Galapagos basidiolichens". Fungal Diversity.

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hygrophoraceaeagaricales-generalichen-generabasidiolichenstaxa-described-in-1965taxa-named-by-derek-reid