445 



finally hit upon the word " consortism " as being especially appro- 

 priate. Reinke gives conclusive evidence that he has not been 

 duly credited with first having pointed out the true conditions met 

 with in the lichen thallus. This credit is given to de Bary, who is 

 generally supposed to have been the first to point out and explain 

 the phenomenon of " symbiosis" * as it occurs in lichens. The 

 author had, however, previously explained this condition in three 

 different publications.f From these it is evident that De Bary was 

 not the discoverer of the phenomenon now known as mutualistic 

 symbiosis, and that the term consortism antedates that of sym- 

 biosis. Reinke explains his views with regard to the lichen-thallus 

 more fully as follows : " We have, therefore, in the thallus of 

 lichens, a consortism, the components of which form a unit, a mor- 

 phological individual, somewhat as the different tissues in a higher 

 plant unite to form the individual. The fact that the alga can ex- 

 ist independently is dependent upon its ability to assimulate car- 

 bon. In the state of consortism, at least in the heteromerous 

 thallus, the alga is nourished by the enclosing fungus ; that is it 

 receives from the hyphae the necessary minerals, nitrogen, oxygen, 

 hydrogen and water. The alga in return supplies the fungus with 

 the essential carbon compounds. From this it is evident that the 

 components (alga and fungus) are biologically associated, mutu- 

 ally dependent upon each other, for the formation of the organic 

 substances required for the upbuilding of the common body." 

 The above is certainly conclusive evidence that Reinke had a cor- 

 rect view of the mutualistic relationship of alga and fungus in the 

 lichen-thallus and furthermore that he was convinced that the 

 lichen formed an autonomous structure. 



The author expresses it as his opinion that the fungi of the 

 higher Ascolichenes no longer exist independently, perhaps never 

 so existed. The alga is, however, still able to lead an independent 

 existence. It is also evident that there are free algae closely re- 

 lated, if not identical with the gonidia of lichens. This fact is of 

 great importance in the consideration of the phylogenetic devel- 



* De Bary, Die Erscheinung der Symbiose. Strassburg, 1879. 



f Reinke, J. Gottinger Nachrichten. p. lOO. 1872. 



Reinke, J. Morphologische Abhandlungen. Leipzig, 1873. 



Reinke and Grisebach, A. S. Oersted's System der Pilze, Lichenen und Algen. 



«873. 



