Mushroom Brief: Reactions to Iron Salts among the Chanterelles
by Michael Kuo
Note, 2015: This page, now 12 years old, used now-outdated species concepts--especially for "Cantharellus cibarius" but also for Cantharellus cinnabarinus and Cantharellus lateritius; see the page for Chanterelles and Trumpets for more information.
Several dozen specimens of Cantharellus from Illinois, Indiana, and Kentucky were tested with iron salts (FeSO4) to determine the color reaction of the flesh and the spore-bearing surface. Species tested included Cantharellus appalachiensis, C. cibarius, C. cinnabarinus, and C. lateritius. C. appalachiensis consistently demonstrated a red color reaction on both the flesh and the spore-bearing surface; C. cibarius and C. lateritius specimens consistently demonstrated a pinkish gray to gray reaction on the flesh and a dark gray reaction on the spore-bearing surface; and C. cinnabarinus consistently demonstrated a negative to very pale grayish reaction on both the flesh and the spore-bearing surface.
Methods were not reliably scientific. Collections of Cantharellus made on forays in Illinois, Indiana, and Kentucky in June, July, and August of 2003 were separated and tested within 3 to 8 hours of collection. A 10% aqueous solution of FeSO4 was applied to the spore-bearing surface and the flesh in the upper stem with an eye dropper. Color reactions were recorded for initial collections of each species; data for further collections was not recorded, since it did not vary. Specimens were not saved.
Approximately five collections from Indiana, Illinois, and Kentucky, were tested. In all collections the reaction of both the flesh and the spore-bearing surface was red.
Approximately six collections from Indiana and Illinois were tested. In all collections the reaction of the flesh was initially reddish, then soon grayish to pinkish gray; the reaction of spore-bearing surface was promptly dark grayish to bluish gray.
Approximately four collections from Illinois were tested. In all collections the reaction of both the flesh and the spore-bearing surface was negative or very pale grayish.
Approximately ten collections from Illinois and Indiana were tested. In all collections the reaction of the flesh was pinkish gray to gray; the reaction of the spore-bearing surface was, initially, either reddish or pinkish gray to grayish, but soon dark gray.
The results of this unscientific examination uphold the assertion of Bigelow (1978) that Cantharellus appalachiensis is unique among the chanterelles in demonstrating a sustained red reaction to iron salts on the flesh and the spore-bearing surface. Since faded specimens of C. appalachiensis that approximate C. cibarius in cap color are sometimes encountered, the application of iron salts may help to separate the two species.
Cantharellus cinnabarinus is apparently unique among the chanterelles in its lack of a particularly strong color reaction to iron salts. However, the color of the fruiting body of C. cinnabarinus is a reliable and definitive separator, and the application of iron salts would not be required to separate this species from the other chanterelles.
Unfortunately, from an identification standpoint, the application of iron salts does not appear to help in separating Cantharellus cibarius from C. lateritius. While minor differences were observed, such as the tendency of some specimens to show reddish hues on one or the other surface before resolving to gray, these differences were not consistent, and the best that can be said is that both species demonstrate pinkish gray to gray reactions on the flesh and gray reactions on the spore-bearing surface. These two species, in their most "typical" forms, are easily separated by examining the spore-bearing surface, which is smooth or slightly wrinkled in C. lateritius and gill-like in C. cibarius. But smooth collections of C. cibarius and wrinkled to nearly gill-like collections of C. lateritius are frequently made. Since microscopic separators are also not definitive, collectors of these confusing specimens have little to rely on for certainty in identification.
Cite this page as:
Kuo, M. (2003, November). Mushroom brief: Reactions to iron salts among the chanterelles. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/kuo_06.html