Description
''Rhynia gwynne-vaughanii'' was first described as a new species by Robert Kidston and William Henry Lang, William H. Lang in 1917. The species is known only from the Rhynie chert in Aberdeenshire, Scotland, where it grew in the vicinity of a silica-rich hot spring. ''Rhynia'' was a vascular plant, and grew in association with other vascular plants such as ''Asteroxylon, Asteroxylon mackei'', a probable ancestor of modern clubmosses (Lycopsida), and with pre-vascular plants such as ''Aglaophyton major'', which is interpreted as basal to true vascular plants. ''Rhynia'' is thought to have had wikt:deciduous, deciduous lateral branches, which it used to disperse laterally over the substrate and stands of the plant may therefore have been cloning, clonal populations. Evidence of the gametophyte alternation of generations, generation of ''Rhynia'' has been described in the form of crowded tufts of diminutive stems only a few mm in height, with the form genus name ''Remyophyton delicatum''.H. Kerp, N.H. Trewin and H. Hass (2004) New gametophytes from the Early Devonian Rhynie chert. Transactions of the Royal Society of Edinburgh, Earth Sciences, 94, 411–428 Like those of ''Aglaophyton major'', ''Horneophyton lignieri'' and ''Nothia (plant), Nothia aphylla'' the gametophytes of ''Rhynia'' were dioicous, bearing male and female gametangium, gametangia (antheridium, antheridia and archegonium, archegonia) on different axes. A significant finding is that the axes of the gametophytes were vascular, unlike almost all of the gametophytes of modern pteridophytes except for that of ''Psilotum''.Taxonomy
Two species of ''Rhynia'' were initially described by R. Kidston and W. H. Lang from the Rhynie chert bed: ''R. gwynne-vaughnii'' in 1917, and ''R. major'' in 1920. ''R. gwynne-vaughanii'' was named by Kidston and Lang in honour of their late friend and colleague, the botanist David Thomas Gwynne-Vaughan. A study of the vascular tissue of the two by David Sydney Edwards, David S. Edwards in 1986 lead to the conclusion that the cell walls of the water-conducting cells of ''R. major'' lacked the secondary thickening bars seen in the xylem of ''R. gwynne-vaughanii'', and were more like the water-conducting Hydroid (botany), hydroids of moss sporophytes. His conclusion was that ''R. gwynne-vaughanii'' belongs in the vascular plants, while ''R. major'' belongs among the bryophytes. Accordingly, he transferred it to a new genus ''Aglaophyton'', leaving ''R. gwynne-vaughnii'' as the only known species of ''Rhynia''. ''Rhynia'' is the type (biology), type genus for the rhyniophytes, established as the subdivision Rhyniophytina by Banks, but since treated at various ranks.Phylogeny
In 2004, Crane et al. published a cladogram for the polysporangiophytes, in which ''Rhynia'' and the other Rhyniopsida, Rhyniaceae are placed as basal vascular plants (tracheophyes).References
{{Taxonbar, from=Q310514 Early Devonian plants Prehistoric plant genera