Common Collybia

Description

Common Collybia is a small mushroom with a cap 1.5–6 cm across, smooth and bald, in colours from cream and ochre to reddish-brown. The colour changes with moisture: after rain the cap darkens, in dry weather it becomes paler, especially at the margin. The gills are very crowded and brittle, white or cream, and the thin, hollow stem is similar in colour to the cap. At its base you can see white threads of mycelium, which are often pulled out together with the mushroom.

It grows in deciduous and coniferous forests, on forest meadows, in parks and gardens, as single fruiting bodies, in clumps, arcs or rings. Fruiting bodies appear from spring to December, often when there are few other mushrooms. In Poland it is very common.

It can be confused with the fairy ring champignon, which has an elastic stem, more distant gills and grows in meadows and pastures, and with other Gymnopus species, e.g. the stinking Gymnopus with its smell of rotten cabbage. Common Collybia is classed in the catalogue as inedible, and gastrointestinal disorders have been reported after eating it, so it should not be collected for consumption.

Identification features

Cap

Diameter 1.5–6 cm; bell-shaped or convex when young, later flat, irregular in older specimens. Surface smooth, bald. Colour pale ochre, reddish-yellow, yellowish-brown to reddish-brown; the mushroom is hygrophanous: pale brown after rain, pale cream in dry weather, with a darker centre. Margin usually not grooved, wavy and uneven in older specimens.

Hymenophore (underside of the cap)

Gills very crowded, thin and brittle, narrowly attached to the stipe (detaching with age), initially white, later ochre-cream.

Stem

Height 2–8 cm, thickness 2–6 mm, cylindrical, hollow like a tube, brittle, sometimes slightly thickened at the base. Surface smooth and bald, ochre-brown, similar in colour to the cap. Base entwined with white to yellowish threads of mycelium, which are often pulled out together with the fruiting body. No ring.

Flesh

Thin, whitish, watery. Taste and smell indistinct. The flesh should not be tasted.

Spore print and spores

Spore print white. Spores ellipsoid to slightly tear-shaped, smooth, colourless, non-amyloid (not reacting in Melzer's reagent), about 5–6.5 × 2.5–3.5 µm.

Habitat and distribution

Ecology. Terrestrial saprotroph, growing on soil among leaves and grasses, on both acidic and alkaline substrates; sometimes on dead, fallen aspen trunks, and occasionally attacking living wood. The epithet dryophilus means “oak-loving”, but the mushroom also grows under many other deciduous and coniferous trees. The fruiting bodies sometimes bear outgrowths of the parasitic fungus Syzygospora mycetophila or S. tumefaciens.

Distribution. Widespread in the temperate zone of the Northern Hemisphere (Europe, North America). In Poland very common: in coniferous and deciduous forests, forest meadows, parks, orchards and gardens, often in arcs and fairy rings; it also occurs in clumps on bark mulch spread in plantings. It is not legally protected in Poland.

Fruiting. From April or May to December; it often appears when there are few other mushrooms.

What can it be confused with?

• Marasmius oreades (fairy ring champignon) — Elastic, tough stem, distant gills; grows in meadows and pastures. Both species form fairy rings.
• Gymnopus hariolorum (stinking Gymnopus) — Smell of rotten cabbage and felty-bristly mycelium at the base of the stem.
• Gymnopus aquosus (watery Gymnopus) — Paler cap and stem thickened at the base.
• Rhodocollybia butyracea — Spore print pinkish, and some of the spores turn reddish-brown in Melzer's reagent.

Never rely on a single feature. If you are not sure — do not pick it; show the mushroom to a qualified mushroom expert.

Interesting facts

• The epithet dryophilus comes from Greek and means “oak-loving”, although the mushroom grows under many tree species; until recently it was most often described as Collybia dryophila.
• It is sometimes regarded as a “weed” mushroom, because it is so common and fruits from spring to December.
• The fungus Syzygospora mycetophila sometimes parasitises the fruiting bodies, forming pale outgrowths on the surface.
• It was first described in 1790 as Agaricus dryophilus; its current genus name was given by Murrill in 1916.