Petticoat Mottlegill

Petticoat Mottlegill is the archetypal dung fungus of grazed pasture, standing tall and slender above horse and cattle droppings. The common name refers to the row of small whitish veil fragments that hang like a lace fringe from the cap margin in fresh specimens.

Panaeolus means all variegated, a reference to the mottled gill faces created by patches of spores ripening at different rates. As the gills darken to black, the mottling becomes very obvious and is the single best genus character in the field.

Several names have been applied to variations of this fungus, including P. sphinctrinus and P. campanulatus, which are now generally treated as forms of one variable species. Whatever the label, the combination of dung substrate, bell-shaped grey cap, fringed margin, and jet-black spores is consistent.

Cap

Usually 1.5-4 cm across and about as tall, conical to bell-shaped and never expanding flat. The surface is smooth, grey to grey-brown, sometimes with an olive or reddish flush, becoming paler and often finely cracked in dry weather. The margin carries small triangular whitish veil teeth, most obvious when young and easily washed off by rain.

Gills

Adnate, moderately crowded, broad, pale grey at first and then heavily mottled with black patches as the spores ripen unevenly, finally almost uniformly black. The gill edges stay narrowly white, giving a fine pale line along each gill.

Stipe

Tall, straight, and slender, 6-12 cm high and 2-4 mm thick, hollow and rather rigid, grey-brown to reddish brown, often paler and pruinose at the apex and darker towards the base. No ring is present.

Flesh & spore print

The flesh is thin and greyish. The spore print is jet black, one of the darkest deposits among grassland fungi, and the spores are smooth under the microscope.

It fruits directly on the dung of horses, cattle, sheep, and other herbivores, and on strongly manured or heavily grazed pasture where dung has been broken down into the turf. Fruit bodies appear singly or in small scattered groups, often with several at different stages on one dung pat.

The season runs from spring through late autumn wherever the ground is warm and moist, and in mild regions it may fruit year round. The species is cosmopolitan, occurring on every inhabited continent alongside grazing livestock.

Panaeolus papilionaceus is a coprophilous saprotroph, feeding on the partly digested plant fibre in herbivore dung. Spores are commonly ingested with grass, pass unharmed through the animal's gut, and germinate in the deposited dung, a dispersal cycle shared by many dung fungi.

Because dung is a rich but short-lived resource, the fungus grows and fruits quickly, producing tall stems that lift the cap clear of the pat so spores can be carried away by air currents. Colonisation follows a predictable succession, with this species typically appearing after the earliest moulds and cup fungi have run their course.

Panaeolus foenisecii grows in turf rather than on dung, has a rounder hygrophanous brown cap that dries in pale zones, lacks veil teeth on the margin, and gives a purplish-brown rather than jet-black spore print. Panaeolus cinctulus is also dung-associated but has a broader, flatter reddish-brown cap with a darker marginal band and no marginal veil fringe.

Panaeolus semiovatus is larger and paler, with a smooth whitish to buff cap and a distinct membranous ring on the stem. Psathyrella species on dung-enriched ground are more fragile, with brittle white stems and purple-brown rather than black spore deposits.