I hope you can help me ,we have a strange " fungus" it looks like seaweed that you would find on rocks at the beach ,it has no root or anchor ,it is spreading around the garden as individual clumps with no connection with each other .as we have a pup ,I am rather concern ,although she doesn't show any interest in eating it.photos attached



,it isn't on any rotten wood etc only on concrete or stone

@cardyl Your photos didn't upload. Try them again. I know for myself if I move too fast and don't wait until it says "photo processed" they won't attach.

Sounds like Nostoc. A cyanobacteria. Harmless.

An interesting organism now called Nostoc.
May not be a great thing to have living on walkways, otherwise it seems pretty harmless.
Here's a link to some US based information, I don't know if any products mentioned are available in the UK.

https://bygl.osu.edu/node/1258