A similar plant was described in 1844 by Schimper and Mougeot[578] from the Bunter rocks of the Vosges as _Schizoneura paradoxa_. This species bears a very close resemblance to the Indian forms, and indeed it is difficult to point to any distinction of taxonomic importance. Feistmantel considers that the European plant has rather fewer segments in the leaf-sheaths, and that the Indian plant had somewhat stronger stems. Both of these differences are such as might easily be found on branches of the same species. It is, however, interesting to notice the very close resemblance between the Lower Trias European plant and the somewhat older member of the _Glossopteris_ flora recorded from India and other regions, which probably once formed part of that Southern Hemisphere Continent which is known as Gondwana Land[579]. CHAPTER X. I. EQUISETALES (_continued_). (CALAMARIEAE.) In order to minimise repetition and digression the following account of the Calamarieae is divided into sections, under each of which a certain part of the subject is more particularly dealt with. After a brief sketch of the history of our knowledge of _Calamites_, and a short description of the characteristics of the genus, the morphological features are more fully considered. A description of the most striking features of the better known Calamitean types is followed by a short discussion on the question of nomenclature and classification, and reference is made to the manner of occurrence of _Calamites_ and to some of the possible sources of error in identification. D. CALAMITES. I. Historical Sketch. In the following account of the Calamarieae the generic name _Calamites_ is used in a somewhat comprehensive sense. As previous writers have pointed out, it is probable that under this generic name there may be included more than one type of plant worthy of generic designation. Owing to the various opinions which have been held by different authors, as to the relationship and botanical position of plants now generally included in the Calamarieae, there has been no little confusion in nomenclature. Facts as to the nature of the genus _Calamites_ have occasionally to be selected from writings containing many speculative and erroneous views, but the data at our disposal enable us to give a fairly complete account of the morphology of this Palaeozoic plant.