🍄 Introduction

Coprinellus disseminatus, the fairy ink cap or trooping crumble cap, is among the most distinctive of all agarics, fruiting in enormous troops of hundreds to thousands of tiny, pleated caps clustered around the bases of dead deciduous stumps and buried wood. Unlike other ink caps, it rarely fully deliquesces into ink; instead the caps wither and crumble. The species is harmless, non-toxic, and ecologically important but too small and insubstantial to have any culinary value.

Individual caps are 0.5–1.5 cm across, oval to broadly bell-shaped, deeply striate-pleated from margin nearly to centre, pale grey to grey-buff with a slightly ochre tint at the disc. The surface is smooth and silky, without granules. Gills are white becoming dark grey to black, widely spaced. Stipes are white, threadlike, 1–4 cm tall, hollow and extremely fragile, without a ring. Flesh is essentially absent — the caps are purely the cap cuticle and gill tissue with minimal flesh. The entire fruiting body is delicate and transparent-looking.

Quick Facts

🔍 Identification Guide

The combination of enormous numbers, tiny size, deeply pleated grey caps, and wood-substrate clustering is unmistakable in the field. No other British or North American mushroom grows in such dense masses at such small scale. The absence of mica granules distinguishes it from young Coprinellus micaceus. The lack of true deliquescence — caps wither rather than liquefy — is a behavioural difference from other ink caps. Parasola plicatilis is similar in shape but grows singly in grass.

Morphological Features

Detailed Morphology

The deep radial pleating of the cap surface is the most distinctive morphological feature, giving each cap a parasol-like ribbed texture. Unlike most ink caps, the cheilocystidia are of the broadly utriform type rather than the cylindrical type seen in related genera. Basidia are four-spored. The stipes are extremely thin and break under the lightest pressure. Spores are smooth, very dark brown to black in print.

🧬 Taxonomy & Classification

Formerly Coprinus disseminatus. Transferred to Coprinellus following the molecular revision of Coprinus by Redhead et al. (2001). Despite sharing the ink cap growth habit and deliquescence tendency, Coprinellus disseminatus is thought to have acquired its fruiting strategy independently from the larger ink caps, as molecular data places it within a distinct clade. The epithet disseminatus means scattered or dispersed, referring to the mass-fruiting habit.

⚕️ Edibility & Safety

Not toxic but wholly without culinary value due to minute size and almost complete absence of flesh. Not listed as poisonous in any authoritative source. There is no alcohol interaction and no known toxins. The only practical risk is accidentally confusing it with other, larger ink caps if collected carelessly.

⚠️ Look-Alikes & Confusions

Parasola plicatilis is similar in the deeply pleated cap but grows singly in grass and is slightly larger (1–3 cm). Coprinellus micaceus is larger, has mica granules when fresh, and grows in smaller clusters. Coprinus comatus at the button stage is far larger, white, and cylindrical. No seriously toxic species shares the combination of tiny size, mass clustering on wood, and deep pleating.

Known Look-Alikes

🌲 Habitat & Ecology

Strictly saprotrophic on well-decayed deciduous wood, often appearing on the same stump over many consecutive years as the mycelium extends through the wood. Tolerates full shade and very damp conditions. Common in parks and woodlands wherever old stumps remain. The mycelium can produce multiple massive flushes in a single season after rain events. A reliable indicator of advanced wood decay.

Ecological Role

Important decomposer of well-rotted deciduous wood in the later stages of decay succession. Produces large quantities of biomass rapidly and contributes to the breakdown of woody detritus into humus. Fruiting bodies feed numerous detritivores including fungus gnats, springtails, and mites.

🗺 Distribution Map

Known distribution of Fairy Ink Cap: cosmopolitan in northern temperate regions. This species is saprotrophic (saprobic).

🧺 Foraging Guide

Not worth collecting for culinary purposes. Valuable as a teaching species for recognising ink caps and understanding mass-fruiting ecology. Photograph rather than pick.

🌱 Cultivation

Not cultivated. Too small and fragile to have any commercial or culinary interest. Mycelium can be grown on agar for laboratory study.

🍳 Culinary Uses

Not edible in any practical sense — there is essentially no flesh to eat. Even gathering sufficient biomass for a single portion would require hundreds of specimens and is not worth attempting.

📦 Preservation & Storage

Cannot be preserved. Specimens wither within hours of picking. No culinary preservation applications exist.

🩹 Medicinal Properties

No medicinal properties documented. Not used in traditional medicine or modern research applications. The species has attracted no pharmacological attention due to its small size and insubstantial biomass.

🍂 Seasonal Fruiting

Fruits from spring through late autumn, with major flushes after heavy rainfall. A single stump can produce repeated flushes throughout the season. Common in spring in mild climates and one of the last species visible in early winter in temperate Europe.

🔬 Spore Print & Microscopy

Spores are black in mass, ellipsoid to subfusiform, 7–10 × 4–5 µm, with a distinct germ pore. Cheilocystidia broadly utriform, thin-walled. Pleurocystidia absent. Basidia four-spored, clavate. Presence of utriform cheilocystidia without pleurocystidia is a distinguishing microscopic feature separating Coprinellus from Parasola and Coprinopsis.

🌀 Varieties & Forms

No accepted varieties. Populations are morphologically consistent across Europe and North America. The species is cosmopolitan and shows minimal geographic variation.

📜 History & Ethnomycology

Noted by early European mycologists including Fries and Persoon primarily as a curiosity because of the extraordinary massed fruiting. Victorian natural history writers found it photogenic and it appears frequently in early illustrated fungus books. No ethnobotanical uses are recorded.

🎓 Beginner's Guide

An excellent beginner species because it is unmistakable and risk-free. Use it to learn the pleated ink cap cap structure and to study autodigestion in relative slow motion, since disseminatus caps wither rather than fully liquefy. Practice identifying it from photographs before visiting sites, as first-time observers are often astonished by the sheer numbers.

Photography Tips

This is one of the most photogenic of all fungi due to the sheer spectacle of hundreds of pleated caps in dense formation. Wide-angle shots showing the full extent of a flush against a stump are dramatic. Close macro shots of individual pleated caps reveal extraordinary structural detail — each cap is like a miniature ribbed parasol. Shoot in soft, diffuse light for best detail in the pale grey-buff tones. The scale provided by a hand or coin in frame communicates the tiny size effectively.

Common Mistakes

Troubleshooting

If only a few specimens are present near a stump, suspect the flush is either just beginning or mostly finished. Return after the next rain for peak numbers. The extremely fragile stipes mean that attempts to collect specimens in a basket will result in most being broken — use an individual container for any specimens you want to transport intact for study.

❓ Frequently Asked Questions