I’ve been taking pictures of “little plants” for a little while. The most consistent aspect of this photos is that they contain lichen, sometimes moss.
Turns out a lichen is not a plant. See Wikipedia for more info but in short: “A lichen is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.”
Ah well, still going to refer to them as little plants. But let the record show that I now know my error.