Is there any distinct term or phrase (biological or otherwise) for this pattern of mossy growth within a stream-bed?
The photo shows little moss islands on individual rocks, within a very sodden & muddy stream, which had a fairly low flow. I think the photo gives an accurate impression of the gradient of the terrain.
I took this photo yesterday (April 5th) at a time of year when the greenery of the moss is particularly obvious, but I've seen this pattern of growth before in other places as well; I think it is actually quite common at large & small scales. Similar moss enclaves can be found on vertical banks of rock where water weeps out, etc. But I don't have any idea what this might be called (if anything).
(I'm not particularly a plant person, so perhaps an answer will be more obvious to someone else than it was to me! Googling around "moss" and "streams" or rivers seems to be too broad to be useful; probably I don't know the ideal keywords which seem likely to be taxonomic, geological, or otherwise technical.)