Russula: Difference between revisions
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''Russula'' means ''reddish''. |
''Russula'' means ''reddish''. |
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==Taxonomy== |
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[[Christian Hendrik Persoon]] first [[circumscription (taxonomy)|circumscribed]] the genus ''Russula'' in his 1796 work ''Observationes Mycologicae'', and considered the defining characteristics to be the fleshy [[basidiocarp|fruit bodies]], depressed [[pileus (mycology)|cap]], and equal [[lamella (mycology)|gills]].<ref name="Persoon 1796"/> He reduced it to the rank of [[tribe (biology)|tribe]] in the genus ''[[Agaricus]]'' in 1801. [[Elias Fries]] similarly regarded ''Russula'' as a tribe of ''Agaricus'' in his influential ''[[Systema Mycologicum]]'' (1821), but later (1825) raised it to the rank of genus in the ''Systema Orbis Vegetabilis''. Around the same time, [[Samuel Frederick Gray]] also recognized ''Russula'' as a genus in his 1821 work ''The Natural Arrangement of British Plants''.<ref name="Gray 1821"/> |
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==Identification== |
==Identification== |
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[[File:Russula-ochroleuca-taubling.jpg|thumb|right|''[[Russula ochroleuca|R. ochroleuca]]'', [[Germany]]]] |
[[File:Russula-ochroleuca-taubling.jpg|thumb|right|''[[Russula ochroleuca|R. ochroleuca]]'', [[Germany]]]] |
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Like the genus ''Lactarius'', russulas have a [[Russulaceae#Distinctive flesh consistency|distinctive flesh consistency]], which is also reflected in the appearance of the gills and stipe, and normally makes them immediately recognizable. They have no trace of a veil (no ring, or veil remnants on the cap). The gills are brittle except in a few cases, and cannot be bent parallel with the cap without breaking. Hence the genus ''Russula'' sometimes known as 'brittle gills'. They have splitting gills and do not exude a milky substance at cut surfaces, contrary to the genus ''Lactarius''. Presence of large spherical cells, 'sphaerocysts', in the stipe is an important characteristic feature to distinguish the members of Russulaceae from other mushrooms. In ''Russula'', the stipe breaks like the flesh of an apple, while in most other families it only breaks into fibres. <ref name= |
Like the genus ''Lactarius'', russulas have a [[Russulaceae#Distinctive flesh consistency|distinctive flesh consistency]], which is also reflected in the appearance of the gills and stipe, and normally makes them immediately recognizable. They have no trace of a veil (no ring, or veil remnants on the cap). The gills are brittle except in a few cases, and cannot be bent parallel with the cap without breaking. Hence the genus ''Russula'' sometimes known as 'brittle gills'. They have splitting gills and do not exude a milky substance at cut surfaces, contrary to the genus ''Lactarius''. Presence of large spherical cells, 'sphaerocysts', in the stipe is an important characteristic feature to distinguish the members of Russulaceae from other mushrooms. In ''Russula'', the stipe breaks like the flesh of an apple, while in most other families it only breaks into fibres. <ref name="Mohanan 2011"/> The [[spore print|spore powder]] varies from white to cream, or even orange. |
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While it is relatively easy to identify a sample mushroom as belonging to this genus, it is a significant challenge to distinguish member species of ''Russula''. This task often requires microscopic characteristics, and subtle subjective distinctions, such as the difference between a ''mild to bitter'' and a ''mild to acrid'' flavor. Moreover the exact [[phylogenetic]] relationships of these mushrooms have yet to be resolved in the professional mycological community, and may ultimately depend on [[DNA sequencing]] analysis. |
While it is relatively easy to identify a sample mushroom as belonging to this genus, it is a significant challenge to distinguish member species of ''Russula''. This task often requires microscopic characteristics, and subtle subjective distinctions, such as the difference between a ''mild to bitter'' and a ''mild to acrid'' flavor. Moreover the exact [[phylogenetic]] relationships of these mushrooms have yet to be resolved in the professional mycological community, and may ultimately depend on [[DNA sequencing]] analysis. |
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<ref name="Buyck 2008">{{cite journal |author=Buyck B. |title=The edible mushrooms of Madagascar: An evolving enigma |title=Economic Botany |year=2008 |volume=62 |issue=3 |pages=509–520 |doi=10.1007/s12231-008-9029-4}}</ref> |
<ref name="Buyck 2008">{{cite journal |author=Buyck B. |title=The edible mushrooms of Madagascar: An evolving enigma |title=Economic Botany |year=2008 |volume=62 |issue=3 |pages=509–520 |doi=10.1007/s12231-008-9029-4}}</ref> |
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<ref name="Gray 1821">{{cite book |author=Gray SF. |title=A Natural Arrangement of British Plants |volume=1 |publisher=Baldwin, Cradock and Joy |location=London, UK |page=618 |url=http://biodiversitylibrary.org/page/30087320}}</ref> |
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<ref name="Money 2011">{{cite book |author=Money NP. |title=Mushroom |url=http://books.google.com/books?id=QI7TOrbewzUC&pg=PA118 |year=2011 |publisher=Oxford University Press |isbn=978-0-19-973256-2 |page=118}}</ref> |
<ref name="Money 2011">{{cite book |author=Money NP. |title=Mushroom |url=http://books.google.com/books?id=QI7TOrbewzUC&pg=PA118 |year=2011 |publisher=Oxford University Press |isbn=978-0-19-973256-2 |page=118}}</ref> |
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<ref name= |
<ref name="Mohanan 2011">{{cite book |author=Mohanan C. |title=Macrofungi of Kerala |publisher=Kerala Forest Research Institute |location=Kerala, India |year=2011 |pages=597 |isbn=81-85041-73-3}}</ref> |
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<ref name="Persoon 1796">{{cite book |author=Persoon CH. |title=Observationes mycologicae |year=1796 |location=Leipzig, Germany |publisher=Apud Petrum Phillippum Wolf |page=100 |url=http://bibdigital.rjb.csic.es/ing/Libro.php?Libro=5680&Pagina=104 |language=Latin |quote="Pileus carnorufus, utplurimum depressus; Lamellae longitudine aequales."}}</ref> |
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<ref name="Takahashi 1992">{{cite journal |author=Takahashi A, Agatsuma T, Matsuda M, Ohta T, Nunozawa T, Endo T, Nozoe S |year=1992 |title=Russuphelin A, a new cytotoxic substance from the mushroom ''Russula subnigricans'' Hongo |journal=Chemical & Pharmaceutical Bulletin (Tokyo) |volume=40 |issue=12 |pages=3185–8 |pmid=1294320}}</ref> |
<ref name="Takahashi 1992">{{cite journal |author=Takahashi A, Agatsuma T, Matsuda M, Ohta T, Nunozawa T, Endo T, Nozoe S |year=1992 |title=Russuphelin A, a new cytotoxic substance from the mushroom ''Russula subnigricans'' Hongo |journal=Chemical & Pharmaceutical Bulletin (Tokyo) |volume=40 |issue=12 |pages=3185–8 |pmid=1294320}}</ref> |
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Revision as of 06:19, 27 November 2014
| Russula | |
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| The sickener (R. emetica) | |
| Scientific classification | |
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| Genus: | Russula Pers. 1797
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| Diversity | |
| c.700 species | |
Around 750 worldwide species of mycorrhizal mushrooms compose the genus Russula. They are typically common, fairly large, and brightly colored – making them one of the most recognizable genera among mycologists and mushroom collectors. Their distinguishing characteristics include a white to dark yellow spore print, brittle free white gills, and an absence of partial veil or volva tissue on the stem. Members of the related Lactarius genus have similar characteristics but emit a milky latex when their gills are broken. The genus was described by Christian Hendrik Persoon in 1796.
Russula means reddish.
Taxonomy
Christian Hendrik Persoon first circumscribed the genus Russula in his 1796 work Observationes Mycologicae, and considered the defining characteristics to be the fleshy fruit bodies, depressed cap, and equal gills.[1] He reduced it to the rank of tribe in the genus Agaricus in 1801. Elias Fries similarly regarded Russula as a tribe of Agaricus in his influential Systema Mycologicum (1821), but later (1825) raised it to the rank of genus in the Systema Orbis Vegetabilis. Around the same time, Samuel Frederick Gray also recognized Russula as a genus in his 1821 work The Natural Arrangement of British Plants.[2]
Identification
"If we know of any one, who in the pride of intellect spurned all mental tasks as mere play, we would tame him by insisting on his mastering, classifying and explaining the synonyms of the genus Russula."
Like the genus Lactarius, russulas have a distinctive flesh consistency, which is also reflected in the appearance of the gills and stipe, and normally makes them immediately recognizable. They have no trace of a veil (no ring, or veil remnants on the cap). The gills are brittle except in a few cases, and cannot be bent parallel with the cap without breaking. Hence the genus Russula sometimes known as 'brittle gills'. They have splitting gills and do not exude a milky substance at cut surfaces, contrary to the genus Lactarius. Presence of large spherical cells, 'sphaerocysts', in the stipe is an important characteristic feature to distinguish the members of Russulaceae from other mushrooms. In Russula, the stipe breaks like the flesh of an apple, while in most other families it only breaks into fibres. [3] The spore powder varies from white to cream, or even orange.
While it is relatively easy to identify a sample mushroom as belonging to this genus, it is a significant challenge to distinguish member species of Russula. This task often requires microscopic characteristics, and subtle subjective distinctions, such as the difference between a mild to bitter and a mild to acrid flavor. Moreover the exact phylogenetic relationships of these mushrooms have yet to be resolved in the professional mycological community, and may ultimately depend on DNA sequencing analysis.
The following characteristics are often important in identifying individual species:
- the exact colour of the spore powder (white/cream/ochre),
- the taste (mild/bitter/acrid),
- colour changes in the flesh,
- the distance from the centre to which the cap skin can be pulled off: (peeling percentage).
- cap colour (but this is often very variable within one species),
- reaction of the flesh to ferrous sulphate (FeSO4), formalin, alkalis, and other chemicals,
- ornamentation of the spores, and
- other microscopic characteristics, such as the appearance of the cystidia in various mounting reagents.
Despite the difficulty in positively identifying collected specimens, the possibility to spot the toxic species by their acrid taste makes some of the mild species, such as R. cyanoxantha and R. vesca, popular edible mushrooms. Russula is mostly free of deadly poisonous species, and mild-tasting ones are all edible.[4]
Edibility
Humans collect several species of Russula for food. In the Pacific Northwest region of North America, only Russula brevipes parasitized with Hypomyces lactifluorum—known as lobster mushroom—is collected commercially. The tropical Chinese species Russula griseocarnea, misidentified as the European R. vinosa until 2009, is commercially collected as food and medicine.[5] Russula is the most commonly consumed and economically important mushroom genus in Madagascar, particularly Russula prolifica and Russula edulis. This and other edible Russula are typically stripped of their cap cuticle before selling to make them more similar in appearance to the Agaricus bisporus.[6] Several Russula species are sold in the markets of Izta-Popo Zoquiapan National Park (central Mexico): R. brevipes, R. cyanoxantha, R. mexicana and R. olivacea. In Tlaxcala, wild species sold in market include R. alutacea, R. cyanoxantha, R. delica, R. mariae, R. olivacea, R. romagnesia, and R. xerampelina.[7] In Madagascar, species collected from introduced eucalypt forests include Russula madecassense, Russula prolifica, and several other species of minor importance, including some that have not yet been officially described.[8] In Tanzania, Russula cellulata and Russula ciliata are sometimes used as food.[9] Edible russulas in Nepal include Russula flavida and Russula chlorides.[10] Russula cyanoxantha is a popular edible throughout Asia, Europe, and the Pacific.[11] In Thailand, russulas collected by locals and sold in roadsides and local markets include Russula alboareolata, Russula lepida, Russula nigricans, Russula virescens, and Russula xerampelina.[12]
Toxicity
The main pattern of toxicity seen among Russula species to date has been gastrointestinal symptoms in those with a bitter taste when eaten raw or undercooked; many of these are red-capped species such as R. emetica, R. sardonia and R. nobilis. The Asian species Russula subnigricans has been the cause of several fatal cases of rhabdomyolysis in Japan.[13] Several active agents have been isolated; one designated russuphelin A.[14]
Species
- For more examples, see the List of Russula species.
- Russula cyanoxantha - one of the largest species, with blue to greenish cap, mild taste and white, greasy gills.
- Russula emetica - so acrid it can be dried and powdered to make a chilli pepper substitute;
- Russula subnigricans - a poisonous mushroom causing rhabdomyolysis in Japan, China, and Taiwan.
- Russula virescens - an excellent mushroom, easily recognizable by the green and distinctly crackled cap cuticle;
- Russula xerampelina - an edible russula that smells and tastes like shrimp or seafood;
See also
References
- ^ Persoon CH. (1796). Observationes mycologicae (in Latin). Leipzig, Germany: Apud Petrum Phillippum Wolf. p. 100.
Pileus carnorufus, utplurimum depressus; Lamellae longitudine aequales.
- ^ Gray SF. A Natural Arrangement of British Plants. Vol. 1. London, UK: Baldwin, Cradock and Joy. p. 618.
- ^ Mohanan C. (2011). Macrofungi of Kerala. Kerala, India: Kerala Forest Research Institute. p. 597. ISBN 81-85041-73-3.
- ^ See "Russulales News", "Edibility and toxicity of Russulales" page, "5.1.2. Edible Russulae" section.
- ^ Wang X-H, Yang Z-L, Li Y-C, Knudsen H, Liu P-G. (2009). "Russula griseocarnosa sp. nov. (Russulaceae, Russulales), a commercially important edible mushroom in tropical China: mycorrhiza, phylogenetic position, and taxonomy". Nova Hedwigia. 88 (1–2): 269–82. doi:10.1127/0029-5035/2009/0088-0269.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Buyck B. (2008). "Economic Botany". 62 (3): 509–520. doi:10.1007/s12231-008-9029-4.
{{cite journal}}: Cite journal requires|journal=(help) - ^ Dugan (2011), pp. 77–78.
- ^ Dugan (2011), p. 69.
- ^ Dugan (2011), p. 70.
- ^ Dugan (2011), p. 57.
- ^ Dugan (2011), pp. 46, 62.
- ^ Dugan (2011), p. 58.
- ^ Money NP. (2011). Mushroom. Oxford University Press. p. 118. ISBN 978-0-19-973256-2.
- ^ Takahashi A, Agatsuma T, Matsuda M, Ohta T, Nunozawa T, Endo T, Nozoe S (1992). "Russuphelin A, a new cytotoxic substance from the mushroom Russula subnigricans Hongo". Chemical & Pharmaceutical Bulletin (Tokyo). 40 (12): 3185–8. PMID 1294320.
{{cite journal}}: CS1 maint: multiple names: authors list (link)
Cited literature
- Dugan FM. (2011). "Conspectus of World Ethnomycology". St. Paul, Minnesota: American Phytopathological Society. ISBN 978-0-89054-395-5.
{{cite journal}}: Cite journal requires|journal=(help)
- Arora, D. (1986). Mushrooms demystified: A comprehensive guide to the fleshy fungi, Berkeley: Ten Speed Press. pp. 83–103.
- Kibby, G. & Fatto, R. (1990). Keys to the species of Russula in northeastern North America, Somerville, NJ: Kibby-Fatto Enterprises. 70 pp.
- Weber, N. S. & Smith, A. H. (1985). A field guide to southern mushrooms, Ann Arbor: U Michigan P. 280 pp.
- Moser, M. (1978) Basidiomycetes II: Röhrlinge und Blätterpilze, Gustav Fischer Verlag Stuttgart. English edition: Keys to Agarics and Boleti... published by Roger Phillips, London.
- Partly translated from Dutch page.
External links
