Geopora arenosa (Fuckel) S. Ahmad.

Phylum: Ascomycota - Class: Pezizomycetes - Order: Pezizales - Family: Pyronemataceae


This attractive little cup fungus of dry, sandy sites and occasionally also places where wood has been burned on dry light soil develops initially as an underground sphere before breaking through the surface and opening up to form a crown-shaped cup. In some areas Geopora arenosa is fairly common in sand dunes, where it appears close to low-growing shrubs.

Pictures on this page were taken in coastal dunes near Aljezir, in the Western Algarve, Portugal.


Geopora arenosa is an ascomycetous cup fungus, and it is most common in central and southern Europe, where is quite often found in sand dunes and quarry sites or beside reservoirs created from sand extraction. In woodland settings this little cup fungus is sometimes seen on burnt earth, where it pops up conspicuously between pieces of charcoal.

Geopora arenosa is a rare find in Britain. Many of the officially recorded finds are from sandy sites in the English Midlands, notably Herefordshire, Worcestershire and (most often) Warwickshire; however, Geopora arenosa has been found as far north as Aberdeen in Scotland in the New Forest in Hampshire. In Wales these cup fungi have been recorded in two of the National Nature Reserves: Oxwich and Whiteford Burrows, both on the Gower Peninsula.

Taxonomic history

Originally described in 1881 by Karl Wilhelm Gottlieb Leopold Fuckel (1821 - 1876) and named Peziza arenosa, this cup fungus was for many years known as Sepultaria arenosa, a name given to it in 1907 by Jean Louis Emile Boudier (1828 - 1920). Its present accepted name, Geopora arenosa, dates from a monograph by S Ahmad (1910 - 1983) published by the Biological Society of Pakistan in 1978.

Synonyms of Geopora arenosa include Sepultaria sumneriana (Fuckel) Boud., and Peziza arenosa Fuckel.


The generic name Geopora means earth cup, appropriate for cup fungi that grow on/in earth, while the specific epithet arenosa means 'of sand'. The synonymous generic name Sepultaria means underground tomb, and as the cup fungi in this group develop underground and are usually more than half buried even when the cups have opened, the reference seems entirely appropriate.


Poisonous if eaten raw, Geopora arenosa may be toxic even if cooked. In any case the flesh is insubstantial and, in view of the relative rarity of these cup fungi in many areas, it would seem irresponsible to gather them.

Identification Guide


Fertile (inner) surface

Pale cream to greyish beige on the smooth inner (hymenial or spore-bearing) surface, fruitbodies of Geopora arenosa develop over several months as underground spheres before breaking through the surface of the soil and splitting open in the form of typically 5 to 7 fairly regular rays. Up to 2cm tall, the cups are typically 1 to 2cm across when fully open.

Like most cup fungi the flesh of Geopora arenosa is quite brittle.


Infertile (outer) surface and stem

Varying in colour from pale-brown to mid-brown, the scurfy outer surface is infertile and is covered in microscopic light-brown hairs. (The spores are produced on the shiny inner surface of the cup.)



Typically 300µm x 22 µm, with eight spores per ascus.




Ellipsoidal-fusiform, smooth, typically 28 x 17µm; each usually containing one or more often two large oil drops and a number of small ones.

Spore print



Not distinctive.

Habitat & Ecological role

On sandy soil, often in quaries or coastal sand dune systems. Geopora species are thought to be mycorrhizal with various shrubs, but it is reportedly very difficult to determine with certainty the species involved.


These cups can appear any time from spring through to autumn, but in Britain they are most commonly seen between September and November.

Similar species

Geopora tenuis is similar but rather paler; it also appears in dry sandy places, most particularly on sand dune systems.

Geopora sumneriana has a more hairy outer surface and grows exclusively (or almost so) under cedar trees (Cedrus spp.).

Sarcoscypha austriaca, the Scarlet Elf Cup, is bright red and grows on dead twigs and branches, in mossy woods and sometimes under damp hedgerows.

Reference Sources

Fascinated by Fungi, 2nd Edition, Pat O'Reilly 2016, reprinted by Coch-y-bonddu Books in 2022.

Dennis, R.W.G. (1981). British Ascomycetes; Lubrecht & Cramer; ISBN: 3768205525.

Breitenbach, J. & Kränzlin, F. (1984). Fungi of Switzerland. Volume 1: Ascomycetes. Verlag Mykologia: Luzern, Switzerland.

Medardi, G. (2006). Ascomiceti d'Italia. Centro Studi Micologici: Trento.

Dictionary of the Fungi; Paul M. Kirk, Paul F. Cannon, David W. Minter and J. A. Stalpers; CABI, 2008

Taxonomic history and synonym information on these pages is drawn from many sources but in particular from the British Mycological Society's GB Checklist of Fungi.

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