LICHEN, GENUS is a term used to refer to a group of organisms that are composed of both fungi and algae. USNEA (5 letters) and LECIDEA (7 letters) are two genera of lichens that are commonly found in nature. USNEA is a genus of fruticose lichens, which are characterized by their long, branching structures. LECIDEA is a genus of crustose lichens, which are characterized by their flat, crust-like structures. Both genera are found in a variety of habitats, including forests, grasslands, and deserts.