Geopora sumneriana- looking for the Cedar Cup

6361D345-ABC7-4265-AEAA-8318AF1D1AFDFor this post, (and for this month’s CAS article that I have written), I wanted to tell you a little bit about a certain fungus that happens to be a bit special to me. Firstly, it is not terribly common but it is currently fruiting in Kew Gardens, and second, it also happens to be the first fungal fruitbody I ever spotted for myself properly (whilst out on a little foray with a friend, who used to work here in Kew). It was a January day and we were looking for a certain Geastrum campestre (Field Earthstar), which is quite rare but known to fruit beneath one of our Atlas Cedars.


After a short while, we did indeed find some! But before we did, I spotted a rather curious looking cup in the soil; the opening just sat at ground level. I asked what it could possibly be. Once my pal told me what it was, I was immediately intrigued by this ‘creature’ in the earth and couldn’t wait to find more of them, and once I ‘got my eye in’, I found there were actually several about. I went on to find more below other Cedar trees in the gardens and endeavoured to learn more about them. Not a great deal is known about the Cedar cup from what I have seen, and it may well be rare, but I am starting to think it may just be very under-recorded. After all, if it is only solely found with Cedar, then that limits its distribution greatly.
Photo: G.sumneriana. fully open to expose the fertile surface.


Finding the Cedar Cups…
Of course, it’s that time of year again  now, so once a fine day arrived (it’s been a bit, well, soggy recently hasn’t it), me and Oscar were out fungi hunting as standard. We were having a good search through the soil and debris beneath the Cedrus atlantica where I have seen the cups fruiting before. We were shot a few strange looks. Just a few. What could we possibly be looking at? Why was there a pushchair just abandoned at the side of the path? I digress… Anyway, the cups weren’t there, so we would check again and again, week after week, tree after tree, whenever I had a chance to stroll round really. Alas still no Cedar cups. Plenty of beautiful Earthstars around (another type of fungus I am a great lover of) but not quite what I was searching for!

Emerging cups!

Scouting round all the Cedars in the garden, and I finally came across them this week! I was so happy! Oscar was not. He wanted to go home there and then but certainly not before I got some photos! I found them right at the very edge of the bed that this particular tree is situated in, and I observe that these are never situated near the actual stem of the tree; these may be mycorrhizal with the root system so can be generally found further away from the tree. My feeling is that they have some species-specific mycorrhizal connection.


Emerging and opening 


It is usual to find them January to May time. They tend to enjoy dryer soil and in Kew we have sandy loam for soil. One must be quick because it seems the Kew wildlife enjoy sniffing them out to dine on. Badgers, squirrels, who knows- maybe a member of the public is partial to a slice of cedar cup, but somebody certainly likes munching them…  The cups begin as brown, roughly hairy spheres also known as the ascocarp, that are subterranean for quite some time before emerging to the surface and finally pushing through the earth and opening to reveal an almost crown-shaped cup with its fertile spore-bearing surface, and displaying several rays.

A beautiful example of G. sumneriana and the ‘webbing’ across the top of the cup as it opens up

What’s in a name?
As with all nomenclature, I think there’s usually some logical reason for the specimen having that name (or is there?!) Some with perhaps a reference to its appearance, but this one is thought to be named in honour of Francis Bertody Sumner (1874-1945), an American biologist, ichthyologist, zoologist and writer. The genus name, Geopora means ‘earth-cup’, which is quite fitting when this is literally a cup in the earth.
This fungus is exclusive to Cedar trees, although some records of it have been found beneath Yew. (Maybe Cedars were once growing nearby?)
Synonyms of Geopora sumneriana include Sepultaria sumneriana (Cooke) Massee, Sepultaria sumneri (Berk.) Boud., and Peziza sumneriana Cooke.


G. sumnneriana opened…


Habitat and distribution:

Geopora sumneriana is most common in Central Europe, where there is a higher concentration of Cedar trees (Cedrus spp.)

In my experience so far and at present, I am finding the cedar cups exclusively with Cedrus atlantica (Atlas Cedar) and not with other Cedar species. This may just be in Kew but it does seem the favoured species.
According to a source I read at, it states that the ‘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’. It also stated that ‘In Britain, Cedar Cup was reported in exceptionally large numbers during the winter of 2016-17’. And actually, there really were lots of them here in Kew winter 2016-17! So that’s good to hear and to know. Here’s hoping 2018 will be the same. In fact, from what I have seen so far, I think it may well be!

G. sumneriana close to Cedrus atlantica species, RBG Kew


Spreading the love:
Thinking logically, I would say that these fungi spread their spores as an ascocarp by perhaps water droplet and wind dispersal or by a vector. Insects may land on or climb into the cups and wander off adorned with spores to spread. I have seen evidence that animals snuffle these cups out to devour so it seems highly likely that they ingest the fruitbody (I believe mycophagy is the term!) and pass the spores on either through their faecal matter or even on their actual body (noses, snouts). Several places where I found them last year may well play host to them this year too, but when I have gone over to the tree to look, the ground has been dug at (OK, this can always be the pesky squirrels retrieving their hoards too), but Cedar cups do get nibbled so I wouldn’t mind betting there may well have been some there that have now been munched. So, like I said before, you have to be quick!

The Cedar Cup- What it looks like:
The inner fertile surface of the cup is a cream or pale beige colour, and feels and looks very smooth. This surface is known as ‘hymenial’ or ‘spore bearing’, and the cup only opens once the fertile area is ready. As the cup begins to mature from its sphere-like, closed up form, it opens and becomes almost crown-like and displays up to 8 rays. It looks almost like a star shape, and appears as a much broader, shallower cup on the ground. The outer surface is brown, and finely hairy (and inevitably covered in dirt) making them tricky to find. It really is like a little cup in the ground and is truly one of my favourites.

Munched on?!

I have just a little favour of you all: I would love to know if you find any Cedar cups!  You will probably need to scrabble about on the ground as I often do, and so you may well get odd looks. But I’d love to know! So if you do come across one, you can find me at ‘fungifrolics’ on Twitter or Instagram. Do keep a little look out for them and the LAFF (Lost and Found Fungi Project) based here in RBG Kew would love to know of any other whereabouts and records of them too, I am sure!

Until the next time…

Happy fungi hunting!


Photos: My own



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