Chemical tests in mushroom identification
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Iron salts are used commonly in Russula and Bolete identification. It is best to dissolve the salts in water (typically a 10% solution) and then apply to the flesh, but it is sometimes possible to apply the dry salts directly to see a color change. For example, the white flesh of Boletus chrysenteron stains lemon-yellow or olive. Three results are expected with the iron salts tests: no change indicates a negative reaction; a color change to olive, green or blackish green; or a color change to reddish-pink.
Meixner test for amatoxins
- Spores that stain bluish-gray to bluish-black are amyloid
- Spores that stain brown to reddish-brown are dextrinoid
This test is normally performed on white spored mushrooms. If the spores are not light colored, a change will not be readily apparent. It is easiest to see the color change under a microscope, but it is possible to see it with the naked eye with a good spore print.
A 2–3% aqueous solution of phenol gives a color change in some species when applied to the cap or stem.
A 3–10% solution of potassium hydroxide (KOH) gives a color change in some species:
- In Agaricus, some species turn yellow with KOH, some have no reaction, and one species turns green.
- Distinctive change for some species of Cortinarius and Boletes
- Ammirati J, Traquair JA, Horgen PA. (1985). Poisonous Mushrooms of Canada. Fitzhenry & Whiteside in cooperation with Agriculture Canada. p. 40. ISBN 978-0-88902-977-4.
- Beuhler, M; Lee, DC; Gerkin, R (2004). "The Meixner test in the detection of alpha-amanitin and false-positive reactions caused by psilocin and 5-substituted tryptamines". Annals of emergency medicine 44 (2): 114–20. doi:10.1016/S0196064404002860. PMID 15278082.
- Arora, David "Mushrooms Demystified" 2nd Edition, Ten Speed Press, Berkeley, 1986
- Jordan, Michael "The Encyclopedia of Fungi of Britain and Europe" Frances Lincoln 2004
- Kuo, Michael "100 Edible Mushrooms", University of Michigan Press, Ann Arbor 2007
- Largent, David L., Baroni, Timothy J. "How to Identify Mushrooms to Genus VI: Modern Genera" Mad River Press 1988