Rhynia is a genus of extinct vascular plants that lived during the Lower Devonian period, approximately 400 million years ago. While the word "rhynia" is predominantly used to refer to this genus, there are several synonyms that can be used interchangeably. These include Rhyniella, Rhyniophytum, and Aglaophyton. These synonyms are used to denote different species or sub-species of the plant, and are based on differences in morphology, reproductive structures, and other characteristics. The study of plant taxonomy and nomenclature is a fascinating field that allows us to better understand the diversity of plant life throughout the history of our planet.