Community find

Big Laughing Gym

Gymnopilus junonius

Group

gilled mushroom

Spore print

Rusty brown to orange-brown.

Size

Cap diameter: 5-20+ cm; Stipe: 5-20 cm long and 1-5 cm thick.

Season

Commonly fruits in late summer and autumn, often after heavy rainfall.

Habitat

Grows in large clusters (cespitose) at the base of trees, on stumps, or from buried wood. Prefers hardwoods like oak but can be found on conifers.

Distribution

Widespread across North America, Europe, Asia, and parts of the Southern Hemisphere including Australia.

Key characteristics

Large, fleshy mushroom with orange to orange-brown caps often covered in fine scales. Gills are yellow, turning rusty brown as spores mature. The stem is thick, tough, and usually features a distinct ring.

Fruiting body

Cap is convex to flat, 5-25cm wide, dry, and scaly. Gills are adnexed or slightly decurrent, crowded, and change from yellow to rusty orange. The stipe is 5-20cm long, often swollen in the middle or toward the base, with a persistent superior ring.

How to recognise it

Look for the large size, clustering growth on wood, the persistent ring on the stem, and the distinctive rusty-brown spore print that often coats the lower caps in a cluster.

Look-alikes

Omphalotus illudens (Jack-o’-lantern) lacks the ring and has decurrent gills; Armillaria species (Honey Mushrooms) have a white spore print.

Ecological role

Saprophytic, breaking down dead organic matter in wood, and sometimes weakly parasitic on stressed living trees.

Notes

The genus name Gymnopilus means 'naked cap.' It is of scientific interest for its chemical composition and complex taxonomy, as it likely represents a species complex rather than a single species.