Try googling "peziza". I'm not a fungi expert - I've just had an enjoyable trawl through lots of fungi info! I'm not sure that it is the correct ID, but apparently such fungi are very common in bark chippings and are not detrimental to the garden.

Thanks!
Looks like it, doesn't it? Hmmm, they're growing in a container at the moment... still makes me wonder how they got there... maybe it's not got enough drainage... a bit worried there might be something awful buried underneath (but that's just my overactive imagination!)

:-O (Know what you mean, though!)

the fungal mycelium [growth structures]/spores [seeds] may have been in the compost especially if composted bark is used. they are harmless and are in fact releasing nutrients into the soil. harmless doesnt mean edible though! :o)
the dampness will help the fungus to thrive.

I've looked at the Pezizas and I think its probably Peziza Echinospora, especially if the outside is a bit granular? Like some other pezizas it grows on soil, charcoal or old fire sites, so it will be growing on a fragment of something in your compost. It is unrelated to the nematodes. It is inedible, but lets face it, would you be tempted? I really like these! when I was little I would have thought they were like fairy pudding bowls. (Sad isn't it...)

Sweet!

Or yuk, all depending on your viewpoint...

Well.....