I’m on vacation, so only a short written accompaniment today. – Daniel
Porella cordaeana is a liverwort (and the first liverwort entry on Botany Photo of the Day). Liverworts are divided morphologically into two main groups: the leafy liverworts which appear similar to mosses (such as Porella) and the thalloid liverworts. To see the difference in structure, visit An Introduction to Liverwort Morphology via the web site of UBC’s bryophytes course.