Galerina marginata was shown in various studies to contain the amatoxins α-amanitin and γ-amanitin, first as G. venenata, then as G. marginata and G. autumnalis.
G. marginata is thought to be the only species of the amatoxin-producing genera that will produce the toxins while growing in culture.
However, a 20-year retrospective study of more than 2100 cases of amatoxin poisonings from North American and Europe showed that few cases were due to ingestion of Galerina species.
Pholiota mutabilis produces fruit bodies roughly similar in appearance and also grows on wood, but may be distinguished from G. marginata by its stems bearing scales up to the level of the ring, and from growing in large clusters (which is not usual of G. marginata).
A 2005 study again failed to separate the two species using molecular methods, but reported that the incompatibility demonstrated in mating experiments suggests that the species are distinct.
Common names of the species include the "marginate Pholiota" (resulting from its synonymy with Pholiota marginata), "funeral bell", "deadly skullcap", and "deadly Galerina".
The results showed no genetic differences between G. marginata and G. autumnalis, G. oregonensis, G. unicolor, and G. venenata, thus reducing all these names to synonymy.
Like all Galerina species, the spores have a plage, which has been described as resembling "a slightly wrinkled plastic shrink-wrap covering over the distal end of the spore".
The related K. vernalis is a rare species and even more similar in appearance to G. marginata.
Because of differences in ecology, fruit body color and spore size combined with inadequate sampling, the authors preferred to maintain G. pseudomycenopsis as a distinct species.
