The Egghead Mottlegill (Panaeolus semiovatus) is the largest and most distinctive mottlegill in Britain, a tall, pale mushroom that rises straight out of dung. Its cap is shaped like half an egg, cream to pale brown, and sticky when wet, drying shiny and sometimes cracked. The crowded gills become mottled grey and then black as the spores ripen, and have white edges. The long, slender stem carries a thin white ring, which sets it apart from other mottlegills.
It grows on horse and cow dung, singly or in small groups, from April into November.
The Dung Roundhead (Stropharia semiglobata) grows in the same places but has a rounder, yellower cap and a very sticky stem. The Egghead Mottlegill is thin-fleshed and not worth eating, and reports of hallucinogenic compounds in it are inconsistent, so it is best left alone.
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Distribution
Widespread and frequent
Habitat
On horse and cow dung
Etymology
Panaeolus is from the Greek pan, 'all', and aiolos, 'variegated', after the mottled gills. semiovatus is Latin for 'half-egg-shaped', after the cap.
Cap
Semi-ovoid, 3-8 cm across, smooth to slightly wrinkled or cracked. The colour is whitish to pale grey and yellowish-brown, and the surface is viscid when wet, drying shiny.
| Colour | |
|---|---|
| Surface | Smooth, Viscid |
| Width | 3 - 8 cm |
Gills
The gills are adnate and crowded, pale at first, then mottled grey and black as the spores ripen. The margins stay white, giving a neat contrast with the dark gill face.
| Colour | |
|---|---|
| Attachment | Adnate |
| Spacing | crowded |
Flesh
The flesh is thin, fragile and brittle, and yellowish-brown throughout. The smell ranges from absent to earthy, and is never strong.
| Colour | |
|---|---|
| Odour | Nil to earthy |
Stem
The stem is smooth, buff and slender, 8-20 cm tall, and paler above. It carries a thin, ascending white ring, which may be lost with age.
| Colour | |
|---|---|
| Height | 8 - 20 cm |
| Width | 3 - 10 mm |
| Texture | Smooth |
Spores
The spores have an eccentric germ-pore, set to one side of the spore end.
| Colour | |
|---|---|
| Shape | Ellipsoid |
| Ornamentation | Smooth |
| Size | 18-24 x 9.5-11.5 μm |
Microscopic Features
The pleurocystidia are present on the gill face as chrysocystidia. The cheilocystidia are lageniform (flask-shaped).
| Cheilocystidia | Lageniform |
|---|
Classification
- ↳ Phylum: Basidiomycota
- ↳ Subphylum: Agaricomycotina
- ↳ Class: Agaricomycetes
- ↳ Subclass: Agaricomycetidae
- ↳ Order: Agaricales
- ↳ Family: Galeropsidaceae
- ↳ Genus: Panaeolus
Synonyms
- Panaeolus semiovatus (Sow. ex Fr) Lund. & Nannf.
Reference Sources
T. Læssøe, J. H. Peterson (2019) Fungi of Temperate Europe Vol. 1. Princeton University Press.
G. Kibby (2021) Mushrooms and Toadstools of Britain & Europe Vol. 3. Geoffrey Kibby.
