Charcoal Loving Elf Cup Identification Guide

The First Impression and the Setting

This is a species you identify partly by where you are standing. The setting is burnt ground: last winter's bonfire scar in a plantation, the blackened footprint of a brash pile, the ash and charcoal of a forest fire in spruce or pine. The soil is grey-black, still crunching with charcoal fragments, and often carpeted by the vivid green of pioneer mosses such as Funaria and Ceratodon. That bright moss over black ground is the best search image there is; the cups usually come with it.

From standing height you see nothing, or perhaps a faint orange-brown haze over the burn. The fungus only resolves when you kneel: dozens to many hundreds of small tan cups, scattered or so crowded that their rims press together and distort each other. Once seen, the pale toothed rim against the dark disc is what your eye will latch onto for the rest of the day.

Reading the Fruit Body

Individual apothecia are small, usually three to fifteen millimetres across, occasionally to twenty. They begin nearly closed, like a tiny urn or a drawstring purse with a puckered opening, and expand through a deep goblet stage into a shallow cup, finally becoming almost flat and often splitting or waving at the edge. In a single colony you will find every stage at once, and that developmental spread is itself typical.

Look for a stalk. This is one of the most useful characters at this size. Geopyxis carbonaria sits on a short but distinct stipe, roughly one to four millimetres long, which narrows downward to a point where it enters the ash. The cup is therefore raised clear of the substrate rather than glued flat onto it. Ease one out with a knife tip and check the stalk before doing anything else.

The Fertile Surface and the Outside

The inner face of the cup is the hymenium: smooth, matt and evenly coloured, without wrinkles, veins or granules. Colour runs from orange-brown through tan to a warm brick or reddish-tan, deeper and more saturated in wet weather and dulling to a flat ochre when dry.

The outer surface is noticeably paler - whitish-ochre to buff - and finely scurfy or mealy under a lens, sometimes with a faint whitish bloom near the rim.

The rim itself is the clincher. Run a lens along it: the margin is finely toothed, crenulate or scalloped, and it is whitish, so it stands out as a pale beaded fringe against the darker disc. That combination of white toothed rim plus short tapering stalk plus a burnt substrate is effectively the species.

Texture and Section

Cut a cup in half vertically. The tissue is thin, waxy-brittle and pale ochre to whitish. It snaps rather than tearing, and it will crumble if you handle it roughly, so use a blade rather than fingers. There is no latex, no juice and no colour change on cutting - nothing bruises, stains or blues. The stalk in section is solid and continuous with the cup wall.

Reading the Spores

This is an ascomycete, so a conventional overnight spore print is not how it is done. The spores are shot upward from the inner surface in a single synchronised discharge. Bring a fresh clump indoors into warm air, or simply breathe steadily onto it for a few seconds, and watch against a dark background: the cups puff a visible white smoke of spores. Doing that in the field, in low sun, is one of the small pleasures of this group.

If you want a deposit, invert a fresh cup over a glass slide or dark card in a closed box for an hour or two and you will get a faint whitish film. Under the microscope the spores are hyaline, smooth-walled and elliptical, roughly thirteen to eighteen by seven to nine micrometres, without conspicuous oil drops, and they sit eight to an ascus.

Substrate and Season

The substrate is burnt ground in the strict sense: charcoal, ash, and the fire-altered soil beneath, rather than the burnt wood of standing trunks. The strongest association is with conifer forest, especially Norway spruce and pine, where the species commonly appears in extraordinary quantity in the first or second growing season after a burn and then fades away as the site revegetates.

The main season is spring into early summer, sometimes with a lesser autumn showing. The fungus is generally treated as a pyrophilous species with a link to conifer roots, and its explosive post-fire fruiting reflects a strategy of holding on in the soil until fire clears the competition.

Separating the Look-alikes

Geopyxis vulcanalis is the closest relative. It is paler, more ochre-yellow, on average larger, has a less obviously toothed and less white margin, and it turns up on unburnt needle litter and soil rather than on burn scars.

Tarzetta cupularis and T. catinus grow on bare unburnt soil, are greyish to whitish-buff rather than warm tan, have thicker tissue, deeper cups and a coarser toothed rim.

Anthracobia melaloma and its relatives share the burnt ground exactly, but they are sessile discs pressed flat to the ash with no stalk at all, brighter orange, generally smaller, and their margins carry small tufts of brown hairs visible under a lens.

Pyronema omphalodes covers burnt soil in confluent pinkish-orange gelatinous cushions with no cup shape and no stalk - a completely different silhouette.

Peziza species of burnt ground (P. praetervisa, P. violacea, P. echinospora) are sessile, larger, fleshier, and typically carry violet, purplish or dark brown tones.

Sphaerosporella brunnea and Trichophaea species are small brown to orange discs clothed in stiff dark hairs, again without a stalk.

Scutellinia species on damp burnt wood are scarlet with long black eyelash hairs around the rim, unmistakable under a lens.

Working Checklist

Small tan to brick cup, three to fifteen millimetres; short tapering stalk; pale scurfy outside; whitish finely toothed rim; brittle pale tissue with no colour change; puffs white spores; gregarious in hundreds on charcoal and ash in conifer country; spring to early summer, in the first seasons after fire.