Conical Brittlestem

Long known as Psathyrella conopilus, this species has been shifted into Parasola on the strength of molecular work and the stiff cap setae it shares with Parasola auricoma. It sits awkwardly between two worlds: it has the tall, brittle, hollow stem and hygrophanous cap of a classic brittlestem, but the bristled cap surface and dark spores of the pleated inkcaps.

It is one of the most immediately recognisable of the small brown mushrooms simply because of its proportions. The stem is extraordinarily long and thin relative to the small conical cap, so a fruit body can stand 15 cm tall on a stipe barely 3 mm thick, swaying at the slightest breath of air. The cap is markedly hygrophanous, so a single troop photographed over a morning appears to change colour as the caps dry from dark reddish-brown to pale ochre-buff.

It is a common fungus of gardens, hedge banks, mulched beds and shaded path edges, but its fragility means it is often reduced to a tangle of broken stems by the time it reaches a collecting basket.

Cap

1.5-4 cm across and often as tall as wide, narrowly conical to bell-shaped, never fully flattening, the margin sometimes splitting in age. When moist it is a rich dark date-brown to reddish chestnut; as it dries it fades from the centre outward to ochre, pale tan or almost greyish-buff, so caps in different states of hydration look like different species. The surface is smooth to the naked eye but carries scattered erect, thick-walled brown hairs that a hand lens reveals along the margin silhouette. Faint radial lines show through the moist cap.

Gills

Adnexed and narrow, crowded, pale greyish-brown at first, darkening through purplish-brown to blackish as the spores ripen. The gill edges are whitish and finely fringed.

Stipe

Remarkably long, 8-20 cm, and only 2-4 mm thick, white to very pale cream, hollow, rigid but exceedingly brittle, snapping cleanly like a piece of chalk. The surface is smooth to finely silky with a slightly downy base, sometimes with a short rooting extension into the substrate. No ring is present.

Flesh & spore print

The flesh is very thin, watery brown when moist, pale when dry, and without notable odour. The spore print is dark blackish-brown with a purplish cast.

It grows on rich, humus-laden ground, especially where woody debris has been incorporated: mulched borders, the edges of woodchip paths, hedge banks, shaded lawns, compost-enriched garden beds, road verges under trees and the litter of parks and churchyards. It is frequently associated with buried wood, and troops often mark the line of a long-rotted root or a buried plank.

The species is widespread through Europe and North America and is found across temperate regions. It fruits from late spring to late autumn, most heavily in the damp weeks of early autumn, appearing in scattered troops rather than tight clusters. Individual fruit bodies last a day or two at most, collapsing rather than deliquescing.

This is a litter and wood-fragment saprotroph. Its mycelium colonises the humus layer and the small pieces of decaying wood within it, breaking down cellulose and lignin residues left behind by earlier decomposers and helping convert coarse woody debris into soil organic matter.

The tall, thin stipe serves a clear purpose in this habitat: by lifting the small cap well clear of dense litter and grass, the fungus places its spores where even slight air movement can carry them away, compensating for a fruit body far too flimsy to force its way through obstacles. The cap setae, as in Parasola auricoma, appear to reinforce a very thin cap during rapid expansion.

Psathyrella candolleana is broader-capped, pale ochre to whitish, and carries white veil fragments hanging from the cap margin, and it grows in tufts on and around hardwood stumps rather than as scattered singles. Psathyrella spadiceogrisea is similar in colour but has a stouter, shorter stipe and lacks cap setae.

Parasola auricoma shares the bristled cap but is much shorter-stemmed and its cap opens flat and deeply pleated rather than staying conical. Panaeolus species such as P. acuminatus also have conical caps and dark spores, but their gills are distinctly mottled black-and-grey as the spores ripen unevenly, and their cap surfaces are smooth and free of setae.