What is symbiosis?

refers to the close and persistent among agencies of different species. For the agencies involved are called symbionts.
The German botanist Anton de Bary in 1873 (or 1879, according to authors) coined the term "symbiosis"to describe the close relationship between organisms of different kinds. Specifically defined as living together of two dissimilar organisms, usually in close association, usually with beneficial effects for at least one of them.

 

Examples:  algae, moss and mycorrhizae (fungi)