Mystery 'plant' ID please

Hi, my sister found these growing in container in her greenhouse (it contained soil from the garden). She removed some a month ago and then 3 more grew. Our Dad didn't know what they were so she sent me a photo but I've never seen them before either. They look more like seedpods than plants but they have a root which certainly suggests they are actually growing in the soil. The 'plant' part is about 10mm long and sort of furry, especially near the top. To look at it resembles an earplug or an African drum as it has that tapered shape. Each one contains about six circular seeds (2mm diameter). I've tried looking at on the internet but haven't been able to find anything remotely similar. Can anybody please identify them?
NB The garden is in rural North Yorks.
Posts
A fungus, possibly Cyathus olla
In the sticks near Peterborough
I'm quite jealous, I love fungi and I've never sen anything like that.
In the sticks near Peterborough
A fungus - of course! I should have guessed that from the time of year alone. I've been sat next to my Mushroom and Fungi spotter's guide the whole time I've been looking on the web - I was thrown off track by the 'seeds' which must contain the spores. Hopefully my sister has left a few and I'll be able to have a look at them when I next visit.
Thank you very much for your help.
There are some really odd looking fungi about aren't there
In the sticks near Peterborough