|gills on hymenium|
|cap is convex or flat|
|hymenium is adnexed|
|stipe is bare|
|spore print is white to cream|
|ecology is mycorrhizal|
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 has also been encountered under introduced pine trees in Australia. It was historically regarded as edible, but in 2014, scientists discovered that it may be poisonous.
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.
The cap is 4–7 cm (1.6–2.6 in) wide and evenly covered in fine grey scales. Convex with a slight boss, it is broadly conical in shape. The whitish stipe is 3–8 cm (1.2–3.2 in) high and 1.5 cm 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.
Distribution and habitat
Tricholoma terreum is found in Europe, where fruiting bodies appear under conifers, particularly pine and spruce, from late summer to late autumn. 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.
With a mild taste, the species used to be regarded as a good edible. It is seen in markets in France, along with Clitocybe nebularis and Tricholoma portentosum. However, some authorities recommend that inexperienced pickers avoid all grey tricholomas. Recent chemical tests show that this species may contain toxins which can cause rhabdomyolysis.
- Fatal toxins found in 'edible' wild mushrooms
- Phillips, Roger (2006). Mushrooms. Pan MacMillan. p. 107. ISBN 0-330-44237-6.
- Lamaison, Jean-Louis; Polese, Jean-Marie (2005). The Great Encyclopedia of Mushrooms. Könemann. p. 89. ISBN 3-8331-1239-5.
- "Tricholoma terreum page". Species Fungorum. Royal Botanic Gardens Kew. Retrieved 2017-03-22.
- "Tricholoma terreum (Schaeff.) P. Kumm., 1871 Synonyms". Global Biodiversity Information Facility. GBIF. Retrieved 2017-03-22.
- "Tricholoma terreum (Schaeff.) P. Kumm., 1871 Synonyms". Dyntaxa (in Swedish). Swedish University of Agricultural Sciences. Retrieved 2017-03-22.
- Bessette AE, Bessette AR, Trudell SA, Roody WC (2013). Tricholomas of North America: A Mushroom Field Guide. Austin, Texas: University of Texas Press. p. 108.
- Marcel Bon (1987). The Mushrooms and Toadstools of Britain and North-Western Europe. Hodder & Stoughton. p. 154. ISBN 0-340-39935-X.
- Courtecuisse, R.; Duhem, B. (2013). Champignons de France et d'Europe (in French). Delachaux et Niestlé. p. 194. ISBN 978-2-603-02038-8. Also available in English.
- Meinhard Moser (1983). Keys to Agarics and Boleti. Translated by Simon Plant. 15a Eccleston Square, London: Roger Phillips. pp. 129–130. ISBN 0-9508486-0-3.
- Haas, Hans (1969). The Young Specialist looks at Fungi. Burke. p. 144. ISBN 0-222-79409-7.
- Grey, Ed and Pat (2006). "FNCV FUNGI GROUP FORAY: LERDEGERG RIVER WALK, JACK CANN RESERVE, BLACKWOOD, 2 July 2006" (PDF). Royal Botanic Gardens Melbourne website- fungimap section. Royal Botanic Gardens Melbourne. Archived from the original (PDF) on August 29, 2008. Retrieved 2009-02-21.
- Keane, Philip J.; Kile GA; Podger FD (2000). Diseases and Pathogens of Eucalypts. Canberra: CSIRO Publishing. p. 84. ISBN 0-643-06523-7.
- Zeitlmayr, Linus (1976). Wild Mushrooms: An Illustrated Handbook. Garden City Press, Hertfordshire. pp. 72–73. ISBN 0-584-10324-7.
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