Geopora sumneriana (Cooke) M. Torre. - Cedar Cup

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

Geopora sumneriana, Cedar Cup

This large cup fungus develops initially as an underground sphere before breaking through the soil surface and opening up to form a crown-shaped cup.

Geopora sumneriana is almost invariably associated with cedar trees (Cedrus spp.). Although there are one or two references in the literature to this ascomycete appearing beneath Yews (Taxus baccata) in Britain, it is possible that there were cedars nearby (or there may have been cedars nearby in the recent past.)

Geopora sumneriana, Cedar Cup, fully opened

The Cedar Cup shown above is fully mature, and the rays have opened out as far as they will go.

Distribution

Geopora sumneriana is a European ascomycete, and it is most common in Central Europe, where cedar trees (Cedrus spp.) tend to be concentrated.

Cedar Cup is a rare find in Britain, perhaps mainly because cedars are non-native trees and their distribution is very patchy. If you travel along the M5 and M50 from Herefordshire through Worcestershire and in to Warwickshire, you will see quite a lot of cedars, and perhaps that is why many of the official records of Geopora sumneriana are from an area just south of the Malvern Hills. Most British sightings of this late winter and spring fruiting cup fungus are from locations further south in England, notably Cambridgeshire and Kent. In Britain, Cedar Cup was reported in exceptionally large numbers during the winter of 2016-17.

Geopora sumneriana, Cedar Cup, Wellingborough, Northamptonshire, England - Copyright Bill Price

Taxonomic history

Originally described by Mordecai Cooke and named Peziza sumneriana, this cup fungus was for many years known as Sepultaria sumneriana, a name given to it in 1895 by George Edward Massee (1850 - 1917), co-founder and first president of the British Mycological Society. Its present accepted name, Geopora sumneriana, dates from a 1976 publication by Spanish mycologist M. de la Torre in Anales del Instituto Botanico A.J. Cavanilles.

Synonyms of Geopora sumneriana include Sepultaria sumneriana (Cooke) Massee, Sepultaria sumneri (Berk.) Boud., and Peziza sumneriana Cooke.

Etymology

The generic name Geopora means earth cup, appropriate for cup fungi that grow on/in earth. The specific epithet sumneriana may be honouring American biologist Francis Bertody Sumner (1874 - 1945) - if you know differently please contact us. 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, it seems quite appropriate.

Toxicity

Poisonous if eaten raw, Geopora sumneriana is said by some authorities to be toxic even if cooked. In any case the flesh is insubstantial and, in view of the rarity of these cup fungi, it would be irresponsible to gather them.

Identification Guide

Cedar Cup, close-up of fertile surface

Fertile (inner) surface

Pale cream to light greyish beige on the smooth inner (hymenial or spore-bearing) surface, Cedar Cups 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 8 irregular rays. Up to 5cm tall, the cups are typically 5 to 7cm across when fully open. The specimen shown here is not yet fully mature, and its star-like rays will fold back further to create a broader, shallower cup with a crown-like rim. (Like most cup fungi the flesh of the Cedar Cup is quite brittle.)

Hairs on exterior of Cedar Cup Geopora sumneriana

Infertile (outer) surface and stem

Varying in colour from orange-brown to reddish-brown, the outer surface is infertile and covered in curly brown septate fine hairs up to 2mm in length with rounded ends and covered in numerous clear crystals.

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Asci and paraphyses of Cedar Cup, Geopora sumneriana

Asci

Hyaline, cylindrical, 330 - 370µm x 16 - 22µm, with eight spores per ascus.

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The septate paraphyses are cylindrical, 3-4µm in diameter with slightly clavate with 5-9µm diameter tips

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Spore, Cedar Cup Geopora sumneriana

Spores

Ellipsoidal-fusiform, smooth, 27-37 x 13-16µm; each usually containing two large oil drops. (The spores are produced on the shiny inner surface of the cup.)

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Spore print

White

Odour/taste

Not distinctive.

Habitat & Ecological role

On dryish soil beneath cedar trees, usually in small groups.

Season

January to May in Britain.

Similar species

Geopora arenosa and Geopora tenuis are much smaller and paler; they appear in dry sandy places, the latter most particularly on sand dune systems.

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

Geopora sumneriana, Cedar Cup, Wellingborough, Northamptonshire - Copyright Bill Price

Reference Sources

Fascinated by Fungi, Pat O'Reilly 2016.

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

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

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.

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 and (for basidiomycetes) on Kew's Checklist of the British & Irish Basidiomycota.

Acknowledgements

This page includes pictures kindly contributed by Simon Harding, Bill Prince and Richard Shotbolt.

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