All this is good news especially if you have a rye grass, broadleaf lawn that is used as a multi-purpose surface and where the finest quality lawn is not required. However, depositing the cuttings back onto the surface of the soil throughout the season inevitably results in a build up of decomposing organic matter. This is known as thatch and if left on fine-leaved lawns, can cause problems harbouring pests and diseases. It can also physically hinder the growth of the grasses. As a result, groundsmen and greenkeepers have traditionally removed the layer of thatch annually in autumn by scarifying with a spring tine rake.
Liverworts thrive on moist, cool soil and usually in a shaded situation.
They typically occur in lawns under the canopy of trees and on badly drained sites. The most effective method of control is to firstly improve the drainage of the lawn. Alternatively, you could push a fork into the lawn over the whole area. You could then try improving the light levels on the lawn by raising or thinning the canopy of any vegetation that is shadowing the lawn. A further alternative, and one that is only usually temporary, is to use a chemical herbicide, obtainable from garden centres.