Synusia

a spatially and ecologically isolated part of a plant community consisting of species of plants of one or more ecologically close life-forms. For example, in forests of the temperate zone there are dozens of synusiae, including those that are layered (trees, shrublets), epiphytic (lichens, mosses, and algae on trunks), epigenous (parasitic fungi on leaves), epixylous (fungi on dead wood), and intrasoil (microorganisms). The concept of synusiae was proposed in 1918 by the German geobotanist G. Gams. He, as well as the Swedish botanist G. E. Du Rietz and the Estonian botanist T. Lippmaa, elaborated the method of synusiae, which uses the synusia as the initial object in the study of vegetation.