Any group of composite organisms made up of a fungus and an algae living in symbiotic association. The fungus provides a structure that may protect the algae from drying and harsh conditions; the algae synthesizes and secretes a specific carbohydrate that is taken up and utilised as food by the fungus.

About 15,000 kinds are found worldwide, especially in harsh environments, usually on rock, bark, or poor quality soils.

Dog Lichen appears as a greyish-black scale called a thallus and is often encountered growing on the lawn. The thallus is papery in dry conditions and plumps up when wet. The lower surface has white root-like structures called rhizines. It is an indication that the drainage is poor and the grass is in poor condition. Usually there will already be moss present for the same reason so dealing with the latter should remove the lichen as well.

A lichen is made up of a fungus and an algae living together in a symbiotic relationship. The fungus provides a structure taking up moisture and nutrients but it does not have the means to convert them to food. The algae can photosynthesise and produces enough nourishment for both using light as the source of energy required. Lichens are known to grow well when pollution levels are low. If the air quality is poor or where acid rain falls there will be fewer present.

The common name arose because of the shape of the fruiting bodies which resemble a dog’s teeth. In the middle ages when such resemblances were thought to be significant it was even used as a treatment for rabies.


Treatment is the same as for moss, therefore scarifiying to initially remove the lichen present in your lawn is the most beneficial process. Aerating and regular feeding should remove the problem from a lawn and help prevent its return.

Depending on the extent of the moss and lichen coverage on your lawn, standard scarification may not be adequate. For particularly poor lawns with heavy moss and lichen, overseeding may be required.

To arrange for a surveyor to inspect your lawn and recommend the best and most suitable course of action, please contact our office on 01292 478833.