Apparently, identifying the species of moss residing on top of a rock in the middle of a river is quite difficult. I put in a call to one of the local moss experts explaining my photograph, naively thinking that there can’t be that many species of mosses living on stream-rocks. It turns out that there can be that many. Similar to terrestrial species of moss, a good macro photograph with fruiting structures (or even better, a specimen in hand) is required to take a stab at identification.
This photograph was taken in-camera and processed a bit less than I normally do. The effect of the water is due to a specialized glass filter and long exposure.