Marchantia polymorpha
The common liverwort has no stems and leaves but a thallus instead. Estonia hosts about 30 species of bryophytes with such a platelet-like, more or less branched growth form. The common liverwort with its up to 15-cm-long and 2-cm-wide thallus branches is one of the largest among them.
The small cup-like structures on its thallus contain tiny disc-shaped reproductive bodies called gemmae. Raindrops splash the disclets out of the cup, enabling them to develop into new liverwort plants under suitable conditions.
The species is very common in Estonia. It prefers to grow on riverbanks, in ditches, wetter forests, as well as damper corners of home gardens.
Gardeners who need to control liverworts invading their garden beds should not only remove the liverwort layer but also aerate the soil and reduce its moisture and fertility. Otherwise the spores and gemmae remaining in the soil will soon develop into new liverwort plants.