What are these?

[hotcookie]

Found loads of them under some weed proof membrane I had down in my raised bed to suppress weeds after them being very neglected.
There was a patch of reeds beside it but I've never seen these before-are they reed seeds? Some sort of insect casing? There were HUNDREDS of them

Some sort of fungus I think, it's called an Earth star.

It is weird

Could you post one or two more close up pictures? To me it looks like a mouse or vole has been caching something - I keep finding piles of acorns, plum stones and walnuts under random things and in odd places in my garden! They do stockpile in autumn, when there is an abundance of fruit, nuts etc, to see them through lean times - not dissimilar to us at the moment!

It could be Hedges but there is a star shaped fungus that looks similar , in my book on British Wildflife, it also changes its shape from young. Maybe it could be googled. I don't\can't do links.

Doesen't look like an earth star to me. It looks like the skeleton of a plant seed pod. Earth stars don't have fibrous bits in them and therefor don't leave skeletons. They start looking vaguely puffball -like then as they ripen the top splits open and turns back in segments so it looks star shaped. They're about conker to pingpong ball shaped from memory - it's a couple of years since I've seen one.

How large are these? It's usually plants in the pea and bean family that have have spiral seed pods, which these look like. Medicago, for example.

It's a dried bur-clover seed, @hotcookie

They are around 4-5mm diameter I reckon. They do slightly separate if you pull them apart.
I'll see if can dig some out from the binbag tomorrow for more photos(council have stopped garden waste collection and I didn't fancy trying to home compost something completely unknown!)

They don't feel as spiky as the burs I remove from my cats tails, but thats a good possibility

They're seeds from the common marigold!
like these

sorry meant to add - photo here - the shape of the seed varies widely on where on the flower head it formed.

Here are some closer up photos

I really don't remember ever having marigolds up there, but it's a possibility

You might not have planted them, but if they were hidden under a membrane it might have been a mouse's stash. I grew pot marigolds in my last garden on a sunny spot by the house and would find little piles of seeds up the other end under the tree where voles lived - also in the kitchen behind the washing machine thanks to mice!

I've got pot marigolds and I've never seen their seeds looking that that. It could be a stash of pine tree fruits. It's a mystery

Not marigolds, too "coiled up" looking for that. Not pine tree fruits either, they don't have that skeleton structure. Burr clover, as suggested above, is Medicago - google medicago seed and see what you think.

So this is them unfurled and what the seeds look like inside
They are soft though rather than spiky, and in the interests of science I've had to plant some to find out for sure 😂

Ah, now like that they could be marigold (Calendula)