Marchantia polymorpha

A garden blip again. This is a liverwort (horrible sounding I know) and is a lower plant. You probably have some in your own garden if you look for them. They're native to shady wet stream and river banks but are frequently found in the compost of potted garden centre plants.
The small cups on the surface are reproductive organs and later on umbrella shaped structures appear. The female 'bit' has a stalk and rays at the top later on..they haven't developed on this one yet.