Tricholoma terreum
{{Short description|Species of fungus}}
{{Speciesbox
| image = Tricholoma terreum 20061105wa.jpg
| taxon = Tricholoma terreum
| authority = (Schaeff.) P.Kumm. (1871)
| synonyms = *Agaricus terreum Schaeff. (1774)
- Tricholoma myomyces (Pers.) J.E.Lange
}}
{{Mycomorphbox
| name = Tricholoma terreum
| hymeniumType = gills
| capShape = convex
| capShape2 = flat
| whichGills = adnexed
| stipeCharacter = bare
| sporePrintColor = white
| sporePrintColor2 = cream
| ecologicalType = mycorrhizal
| howEdible = edible
}}
Tricholoma terreum, commonly known as the grey knight or dirty tricholoma, is a grey-capped mushroom of the large genus Tricholoma. It is found in coniferous woodlands in Europe and North America, and has also been encountered under introduced pine trees in Australia and New Zealand. It is regarded as edible, although toxic in extremely high quantities.
Taxonomy
The fungus was originally described as Agaricus terreus by Jacob Christian Schäffer in 1762, and as Agaricus myomyces by mycologist Christian Hendrik Persoon in 1794. It was given its current binomial name by German Paul Kummer in 1871. It is commonly known as the grey knight from its discoloured gills.
Almost all modern sources consider Tricholoma myomyces to be a synonym of T. terreum, but there are some exceptions. Bon mentions that T. myomyces has been defined for lowland mushrooms with white gills and a fleecy cap and Courtecuisse separates it on the same basis. Moser distinguished T. myomyces on the basis that the gills should go yellow.
Description
The cap is {{convert|4-7|cm|in|frac=4|abbr=off}} wide and evenly covered in fine grey scales. Convex with a slight boss, it is broadly conical in shape. The whitish stipe is {{convert|3-8|cm|in|frac=4|abbr=off}} high and {{convert|1.5|cm|in|frac=4|abbr=off}} wide and has no ring. There is no ring or volva. The whitish flesh is thin, easily broken, and has a pleasant mild (not mealy) smell and taste. The widely spaced and uneven gills are free (unattached to the stipe). The spore print is white, the oval spores 6–7 μm long by 3.5–4.4 μm wide.{{cite book | last = Phillips |first=Roger | year = 2006 | title = Mushrooms | publisher = Pan MacMillan | isbn = 978-0-330-44237-4|page= 107}}{{cite book |title=The Great Encyclopedia of Mushrooms |last=Lamaison |first=Jean-Louis |author2=Polese, Jean-Marie |year=2005 |publisher=Könemann |isbn=978-3-8331-1239-3|page=89}}
It could be confused with the larger (and poisonous) T. pardinum has a mealy smell and cap scales; the edible T. orirubens has fine dark scales and pinkish gills.{{cite book | last = Haas |first=Hans | year = 1969 | title = The Young Specialist looks at Fungi |page= 144| publisher = Burke | isbn= 978-0-222-79409-3}}
Distribution and habitat
Tricholoma terreum is found in Europe (September–December),{{Cite book |last=Francis-Baker |first=Tiffany |title=Concise Foraging Guide |date=2021 |publisher=Bloomsbury |isbn=978-1-4729-8474-6 |series=The Wildlife Trusts |location=London |pages=142}} where fruiting bodies appear under conifers, particularly pine and spruce, from late summer to late autumn. It can be found in much of North America from August to December, and slightly later on the West Coast.{{Cite book |last=Audubon |title=Mushrooms of North America |publisher=Knopf |year=2023 |isbn=978-0-593-31998-7 |pages=495}} They may also arise in parks near these trees, and grow in fairy rings. They are generally in quite densely populated groups though not bunched. It has been recorded growing under exotic Pinus radiata plantations in Australia.{{cite web|url=http://www.rbg.vic.gov.au/fungimap_/__data/page/2903/iFNCV.Blackwood_Report.final.pdf |title=FNCV FUNGI GROUP FORAY: LERDEGERG RIVER WALK, JACK CANN RESERVE, BLACKWOOD, 2 July 2006 |last=Grey |first=Ed and Pat |year=2006 |work=Royal Botanic Gardens Melbourne website- fungimap section |publisher=Royal Botanic Gardens Melbourne |accessdate=2009-02-21 |url-status=dead |archiveurl=https://web.archive.org/web/20080829193758/http://www.rbg.vic.gov.au/fungimap_/__data/page/2903/iFNCV.Blackwood_Report.final.pdf |archivedate=August 29, 2008 }}{{cite book|last=Keane|first=Philip J.|author2=Kile GA |author3=Podger FD |title=Diseases and Pathogens of Eucalypts|publisher=CSIRO Publishing|location=Canberra|year=2000|pages=84|isbn=978-0-643-06523-9}}
Edibility
With a mild taste, the species used to be widely regarded as a good edible. It is seen in markets in France, along with Clitocybe nebularis and Tricholoma portentosum.
One 1970s source recommended that inexperienced pickers avoid all grey tricholomas.{{cite book|last=Zeitlmayr |first=Linus|year=1976|title=Wild Mushrooms: An Illustrated Handbook|publisher=Garden City Press, Hertfordshire|isbn= 978-0-584-10324-3|pages= 72–73}} Chemical tests published in 2014 show that the species may contain toxins which can cause rhabdomyolysis, leading to speculation that the mushroom was poisonous,Heping Xia: [http://www.rsc.org/chemistryworld/2014/06/fatal-toxins-identified-edible-tricholoma-terreum-equestre-wild-mushrooms Fatal toxins found in 'edible' wild mushrooms], in: Chemistry World, 16 June 2014 apparently debunked in 2016.Paolo Davoli, Marco Floriani, Francesca Assisi, Karl Kob, Nicola Sitta: [https://onlinelibrary.wiley.com/doi/abs/10.1002/chem.201406655 Comment on “Chemical and Toxicological Investigations of a Previously Unknown Poisonous European Mushroom Tricholoma terreum ”], in: Chemistry Europe. First published: 10 March 2016, doi:10.1002/chem.201406655 In 2018, research showed that only an abnormal quantity of Tricholoma mushrooms would trigger the rhabdomyolysis, with consumption of about 200 g safe unless there is an individual reaction.Piotr Rzymski, Piotr Klimaszyk: [https://onlinelibrary.wiley.com/doi/full/10.1111/1541-4337.12374 Is the Yellow Knight Mushroom Edible or Not? A Systematic Review and Critical Viewpoints on the Toxicity of Tricholoma equestre], Wiley online library, first published: 25 July 2018, doi:10.1111/1541-4337.12374 A 2024 study also tested for and concluded that toxin levels were negligible enough for T. terreum for it to be considered an edible mushroom.{{Cite journal |last1=Clericuzio |last2=Serra |last3=Vidari |first1=Marco |first2=Stefano |first3=Giovanni |date=15 April 2024 |title=No Evidence Was Found for the Presence of Terreolides, Terreumols or Saponaceolides H-S in the Fruiting Bodies of Tricholoma terreum (Basidiomycota, Agaricales) |url=https://pmc.ncbi.nlm.nih.gov/articles/PMC11052463/ |journal=Molecules |volume=29 |issue=8}}
See also
References
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{{Taxonbar|from=Q27266}}
Category:Fungi described in 1774
Category:Fungi found in fairy rings