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Lichenology, the study of lichens, was Edvard August Vainio's primary field of expertise. Lichens, fascinating organisms resulting from the symbiotic relationship between fungi and algae or cyanobacteria, captivated Vainio's scientific curiosity. These non-vascular plants have a unique lifestyle and diverse ecological roles, contributing to Vainio's decision to become a leading lichenologist, making significant contributions to our understanding of lichen diversity and systematics.