The Present Position of Palaeozoic Botany. 141 



The petrified remains, while they leave nothing to be desired 

 as regards preservation of structure, are almost alwaj's fragmentary, 

 and give comparatively little information as to the habit and external 

 characters of the plants from which they where derived. Hence it 

 is necessary, as far as possible, to correlate them with the remains 

 preserved as casts or impressions, a task which presents great diffi- 

 culties, for it seldom happens that both classes of specimens are well 

 represented at the same horizon. 



Owing to the fragmentary nature of most vegetable fossils it 

 has been the practice of palaeobotanists to give distinct generic and 

 specific names to detached parts of plants, though they may ultima- 

 tely prove to have belonged to one and the same species. Thus, to 

 take what is now perhaps the best known of all fossil plants, Lygino- 

 dendron oldhamium, we find that this name was originally conferred on 

 the stem ; the petioles have been called Bachiopteris aspera, the foliage 

 (in the form of impressions) Sphenopteris Höningliansi\ the roots Kaloiijlon 

 HooJi-eri ; the seeds Lagenostoma Lomaxi and the male organs Crossotheca 

 Höninghausi. This custom of giving names to detached parts of 

 plants, though it adds seriously to the complications of synonymy, is 

 unfortunately not to be avoided; for the separate organs constantly 

 have to be described before their connection is known. For example. 

 Calaniostochys JBinneyana has long been one of the best known of 

 Carboniferous fructifications, but it is still impossible to refer it to 

 the particular species of Calamité to which it belonged. The correct 

 piecing together of fragmentary remains is one of the first objects of 

 the palaeobotanist , and the gradual disappearance of superfluous 

 names affords a measure of his success. 



The recent progress of Palaeozoic Botany has depended in a 

 very great degree on the study of petrified remains, admitting of 

 anatomical investigation, and it is only with the help of specimens 

 of this kind that the nature of the fossils preserved as casts or 

 impressions can be interpreted, and safe conclusions as to affinities 

 arrived at. 



Palaeozoic Vegetation. 



Our subject covers the Botany of the whole Palaeozoic Epoch 

 from the oldest rocks in which plant-remains have been found, up to 

 the close of the Permian formation. Our knowledge, however, of the 

 different periods embraced within this immense range of time, is so 

 unequal that no general sketch of Palaeozoic vegetation can be 

 attempted. In the Silurian, for example, vegetable fossils are so 

 scanty that the data are altogether inadequate to give any idea of 

 the flora of that formation. The Devonian is far richer and of 

 great botanical interest, but its flora urgently needs a critical revision 



