FIFTH SUBDIVISION. 

 FUNGI. 



UNTIL recent years Fungi were looked upon as a great group embracing 

 all Thallophytes which do not vegetate by means of intrinsic chloro- 

 phyll. With the advance of research and the widening of knowledge, a 

 new classification of Thallophytes . was established, mainly by Sachs, 

 which was based on the characters of the sexual organs, and under it 

 groups were constituted composed of Algae and Fungi alike, in recogni- 

 tion of the principle that a mere physiological attribute, such as the 

 presence or the absence of chlorophyll, should be no bar to the bringing 

 together of organisms associated with each other by morphological 

 characters. With the analogy before their eyes of the relationship of 

 flowering parasites devoid of chlorophyll with green Flowering Plants, 

 morphologists readily accepted the proposed grouping, and until a 

 few years ago it was generally adopted. It then became apparent 

 that this step, though in the right direction, exceeded due bounds ; 

 and, with the first publication by de Bary of the classification of Fungi 

 used in this treatise, a new movement, which cannot, however, be justly 

 called a reaction, took place. This classification recognises a main 

 group of Fungi branching off from the Algae (Chlorophyceae), and defi- 

 nitely marked by morphological relationship. This main group differs 

 from the old group of Fungi not only in its internal disposition, but in 

 the exclusion from it of Mycetozoa and Bacteria, though it resembles 

 the old group in its latter days in the inclusion of lichen-forming fungi. 

 As clearly characterising and delimiting the group, the words of de Bary 

 (' Lectures on Bacteria,' p. 2) may here be quoted : 



' The term Fungi denotes a group of lower plant-forms, distinguished 

 by definite characteristics of structure and development, and recognised 

 at once when we see a mushroom or a mould. The members of this 

 group are all, as a matter of fact, devoid of chlorophyll, but they might 

 contain chlorophyll and yet belong to this group, just as a bird may 

 have no apparatus for flight, and yet be allowed to be a bird. To these 

 Fungi, as defined by natural history, and not by physiological characters 



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