To me, there's hardly any such thing. Superficially, many mosses look alike to the novice because of their habit of growing in masses. Frequently, a small handful of what appears at first glance to be one kind of moss will yield four or five species. And sometimes a few stray plants of a less common moss may be found isolated in the midst of a more plentiful species. I never know what I'm going to find.
Bryophytes generally are photosynthetic, having chlorophyll to transform sunlight into energy.
One species, the Luminous Moss, grows principally in the entrances to dark caves or crevices. It is a tiny plant, part of which gathers the faint light rays and reflects them back, giving the plant an eerie glow and its common name. This characteristic is believed to have inspired legends of cave elves and goblins. Another extra-ordinary thing about mosses is the way some species are spread across immense geographic distances. And to make things worse, they may look different wherever you find them.