Chap, v Palaeobotany, 1860-1900 141 



ful addition to the group was Hooker's genus Pachytheca, 

 investigated by Barber in 1889 and 1891. 



Palaeozoic Bacteria were discovered by Van Tieghem 

 in 1879. He claimed to have found both the organisms 

 and the products of their activity. They were carefully 

 studied by Renault in his later years. 



Allusion has been already made to the controversy that 

 arose in consequence of Brongniart's division of the plants 

 now recognized as forming the group of the Calamarieae. 

 Holding that secondary formation of wood was confined to 

 phanerogamic plants, he separated those which showed it 

 from the others, thus splitting up somewhat arbitrarily groups 

 which showed many marks of relationship. His views, how- 

 ever, met with considerable acceptance, being supported by 

 Goeppert in 1864, Grand'Eury in 1877, Schenk in 1883, 

 and Renault in 1885. The opposite view, propounded by 

 Williamson in 1871 and supported by Schimper in 1874, 

 and Stur in 1881, ultimately prevailed, as we have seen. 



The anatomical structure of the Calamites was first 

 studied by Williamson, much of whose early work, published 

 in 1868, was devoted to them. He described the type of 

 stem now known as Arthrodendron, which he named 

 Calamopilys. Binney also wrote a memoir on the group in 

 the same year. Casts of the stems were examined by Stur 

 in 1877, and by J. E. Weiss in 1884. In 1877 Grand'Eury 

 showed that the fossils known by the name of Aster 0- 

 phyllites were really the leaf-bearing branches of Calamites, 

 and Weiss made a similar claim in 1884 f° r the Annularieae. 

 We owe a good deal of our knowledge of the group to 

 Grand' Eury's work, Geologie et Pale'ontologie du bassin 

 houiller du Gard, published in 1890. The structure of 

 Archaeo calamites was described by Solms-Laubach in 1897; 

 casts of its stem and figures of its foliage shoots had been, 

 however, previously figured by Stur in 1875. 



The roots of Calamites were identified by Renault in 



