The following points highlight the four main types of lichen thallus. The types are: 1. Crustose (Crustaceous) Lichens 2. Foliose (Foliaceous) Lichens 3. Fruticose Lichens 4. Squamulose Lichens. Type # 1. Crustose (Crustaceous) Lichens: The thallus is of insignificant size. It is flat, thin usually without any distinct lobes. It is just like a thin […]