176 CLASSIFICATION OF PLANTS. 



of our knowledge by no means enables us to explain. 

 Count Sternber ff *<- ggests the following contradictions and 

 anomalies as arising out of the experiment just described. 

 He fully admits the antiseptic quality of ferns, which, he 

 remarks, had previously been demonstrated in the shipwreck 

 of the late M. Dumont d'Urville, in which his plants having 

 been submerged, and afterwards recovered, the grasses and 

 ferns were saved, while the dicotyledonous plants were lost. 

 He next observes, that it would seem that the equisetacece 

 were all destroyed ; yet this family is well preserved in the 

 period extending from the carboniferous to the chalk groups ; 

 while, on the other hand, the ferns of the tertiary flora must 

 have perished, since we are only acquainted with a few species 

 from the brown coal, which cannot be supposed to represent 

 all the ferns that lived in the tertiary period, seeing that 

 they constitute the majority of the plants from the coal to 

 the chalk, and are also abundant in the present creation. In 

 conclusion, he suggests the probability, that the experiment 

 having been made with pure water, may not have produced 

 the same chemical effects on the plants, as was the case with 

 those of the coal, which were immersed in water so impure 

 and admixed with sediment, as to have deposited the clay- 

 slate in which they are preserved.* 



CLASSIFICATION OF PLANTS. We now proceed to describe 

 the arrangement of the vegetable kingdom in detail, and 

 shall offer a brief description of those fossil plants which are 

 of most frequent occurrence, in treating of the classes to 

 which they belong. 



The vegetable kingdom is divided by M. Adolphe Brong- 

 niart into six classes. 



1. The agamise. 



2. The cellular cryptogamiae. 



3. The vascular cryptogamiae. 



4. The gymnosperm phanerogamic. 



5. The monocotyledonous phanerogamic. 



6. The dicotyledonous phanerogamic. 



The following are the observations of M. Brongniart, 

 explanatory of the above arrangement : 



" The first class is that of the agamies, a term which, how- 



* See Flora der Vorwelt, p. 83. 



