Description:
The common liverwort is a thallose liverwort. The thallus is thin green sheet that you are looking at. The liverwort of the early herbalists was Marchantia polymorpha and one characteristic of all species of Marchantia is that the thalli are thick and opaque. Such a thallus is many cells thick and the cells in different layers within the thallus have different functions.

Flowering:
In the photo the circular cups are gemma cups, each containing what look like tiny green "balls", about half a millimetre in diameter. Each of those is a gemma, an aggregation of cells that can be washed or splashed out of a gemma cup by flowing water or falling raindrops. A gemma that lands in a suitable place will grow into a new liverwort plant. There are also abundant, pin-prick air pores covering the thallus. The plants produce umbrella-like reproductive structures known as gametophores. The gametophores of female plants consist of a stalk with star-like rays at the top. See Second photograph.

Threats:
This liverwort does reasonably well.

Management:
Grows in damp places.