It the seed head of a Clematis of the alpina or montana species - probably alpina this early in the season. Sometimes known as Old Man's Beard.

Aha! Thank you very much - I must favourite you as I will have many other questions as I get to know my garden... :-)

And if you want to really show off, then you could sow the seeds now and in a few years time you could be showing everyone the Clematis what you grewed yersen.
The seed is the brown bit at the end of the fluffy tail and viable ones are fatter than the ones which will not grow.

:-) thank you for that tip Owdboggy :-)