Giant Funnel

The Giant Funnel is among the largest agarics of temperate grassland, with mature caps regularly 15-30 cm across and exceptional specimens approaching 40 cm. Seen from a distance a fruiting ring can look like a line of upturned dinner plates set in the grass.

It belongs to Leucopaxillus, a small genus of thick-fleshed, pale, tough mushrooms with white spore prints, decurrent or notched gills and unusually persistent fruit bodies that dry in place rather than collapsing. The genus name means white Paxillus, referring to a superficial resemblance to the roll-rims in gill attachment and inrolled margin.

What separates L. giganteus from the funnels of Clitocybe and Infundibulicybe is its combination of enormous size, chalky white colour, dense leathery flesh and grassland habitat. The flesh is far tougher than that of any true Clitocybe, and old fruit bodies can persist for weeks.

Cap

The cap is 10-30 cm or more across, at first convex with a strongly inrolled margin, then flat and finally deeply and broadly funnel-shaped with a wavy, often split or upturned margin. The surface is dry, matt to finely suede-like or slightly cracked in age, white to cream when fresh, discolouring to pale ochre, tan or leather-buff from the centre outwards as it matures.

Gills

The gills are very crowded, narrow, thin and deeply decurrent, running well down the stipe. They are white to cream, ageing pale buff or faintly pinkish-cream, and can be peeled away from the cap flesh in a sheet.

Stipe

The stipe is short and very thick relative to the cap, 4-10 cm long and 2-4 cm thick, cylindrical or slightly tapering downwards, white to cream and finely fibrillose. It is solid, firm and tough, and the base carries abundant white mycelium that binds soil and grass roots. There is no ring and no volva.

Flesh and spore print

The flesh is thick, firm to leathery and white, unchanging when cut, with a mealy or faintly sweetish smell. The spore print is white; the spores are small, roughened or minutely warty and amyloid, a microscopic feature typical of Leucopaxillus.

The Giant Funnel is a species of open ground: pasture, meadow margins, roadside verges, parkland, golf courses, downland and grassy woodland edges, usually on nutrient-rich or well-manured neutral to calcareous soils. It avoids deep woodland shade and dense litter.

Fruiting runs from late summer through autumn, often after heavy rain. The fruit bodies characteristically form large arcs and complete fairy rings that may be many metres across, with grass inside and along the ring showing altered colour and growth. The species is widespread across Europe and temperate North America and Asia, though patchy in occurrence.

Leucopaxillus giganteus is a saprotroph of grassland soils and thatch, decomposing dead grass roots and accumulated organic matter. Its mycelium forms a dense, persistent underground mat that advances outward at a steady rate, exhausting nutrients as it goes and producing the classic ring pattern.

Because the mycelium is so dense it can restrict water movement into the soil beneath it, which is why the grass along an active ring often looks stressed or scorched, while the band just outside the ring is stimulated by released nitrogen and grows greener and taller. Rings of this species can be long-lived, reappearing in the same sites over many years.

Clitocybe nebularis is smaller, cloudy grey rather than white, has softer flesh and grows in woodland leaf litter rather than open turf. Infundibulicybe geotropa, the Trooping Funnel, also rings in grassy places but is buff-toned with a taller, more slender stipe and a persistent central umbo in the funnel.

Leucopaxillus candidus and other members of the genus are similar in texture but smaller. Large white Agaricus species growing in the same pasture are immediately separated by their free gills, which darken from pink to chocolate-brown, a ring on the stipe and a dark brown spore print. Large Lactarius species with funnel caps release milk from cut gills, which Leucopaxillus never does.