Galerina

Galerina is a genus of small brown-spored saprotrophic agarics, with over 300 species found throughout the world, from the far north to remote Macquarie Island in the Southern Ocean. This group is most noted for toxic species which are occasionally confused with hallucinogenic species of Psilocybe.

Biological aspects
Galerina fruiting bodies are typically small, undistinguished mushrooms with a typical "little brown mushroom" morphology and a cinnamon-brown spore print. The pileus is typically glabrous and often hygrophanous, and a cortina-type veil is often present in young specimens, though it sometimes disappears as the mushroom ages. Microscopically, they are highly variable as well, though most species have spores that are ornamented, lack a germ pore, and have a plage. Many species also have characteristic tibiiform cystidia. However, there are many exceptions, and many species of Galerina lack one or more of these microscopic characteristics. Ecologically, all Galerina are saprotrophs, growing in habitats like rotting wood or in moss.

Galerina has recently been found to be polyphyletic, consisting of three unrelated clades. Each of these clades corresponds to a subgenus of Galerina, as outlined by Kühner. The great diversity of micromorphology found in Galerina is probably due to the polyphyly of the genus.

Phaeogalera is genus that was segregated from Galerina by Kühner. Phaeogalera resemble Galerina in their habitat, macroscopic appearance, and spore print color, however, their microscopic characteristics (smooth spores with a distinct germ pore and non-tibiiform cystidia) more closely resemble Psilocybe. A recent study confirms the affinity of Phaeogalera and the non-psilocybin Psilocybe.

Chemistry and toxicology
Many (though not all) Galerina contain alpha-amanitin and other amatoxins. Galerina steglichii is very rare, bruises blue and contains the hallucinogen psilocybin.

Identification
The extreme toxicity of some Galerina species means that recognition of Galerina is of great importance to mushroom hunters, particularly those who are seeking hallucinogenic Psilocybe. Species like Galerina marginata may bear a superficial resemblance to Psilocybe cyanescens and other Psilocybe species. Galerina can be distinguished from psilocybian Psilocybe by the following characteristics:


 * Spore print color: blackish-brown to lilac-brown in Psilocybe, rusty brown in Galerina. Spore color can be seen by taking a spore print or by looking for evidence of spore drop on the stipe or on surrounding mushrooms.


 * Staining reaction: Psilocybian Psilocybe fruiting bodies stain blue to varying degrees when bruised, while Galerina do not. The strength of this reaction varies with the amount of psilocin present in the tissues of the mushroom. Fruiting bodies with little psilocin will stain weakly if at all, while sporocarps with a high psilocin content will stain strongly blue. Only one rare Galerina has blue-staining tissue, though in some cases the flesh will blacken when handled, and this may be misinterpreted as a bluing reaction.

Since mixed patches of Psilocybe and Galerina can occur, it is essential to be sure of the identity of each sporocarp collected.

Galerina also present some risk of confusion with several species of small edible mushrooms, notably Kuehneromyces mutabilis and "candy cap" Lactarius (L. camphoratus, L. fragilis, and L. rubidus). 

Notable species
Galerina vittiformis is the type species of the genus Galerina. Var. pachyspora has been collected on Macquarie Island.

Galerina marginata (also known as autumn skullcap, or deadly galerina) is a poisonous species found throughout the temperate regions of the world, in habitats as diverse as forests and urban parklands, wherever rotting wood is found. DNA studies found that Galerina autumnalis and five other species of Galerina with similar morphologies were, in fact, synonyms of Galerina marginata.

Galerina sulcipes, a lethal species found in Indonesia and responsible for deaths there. One study found it more toxic than Amanita phalloides.

Several Galerina species are listed by the US Forest Service as "species of special concern" in the Northwest Forest Plan. These species are considered indicator species for old growth coniferous forest in the Pacific Northwest: Galerina atkinsonia, Galerina cerina Galerina heterocystis , Galerina sphagnicola , and Galerina vittiformis.