21 



that a thorough study of the life-history, morphology and physiology 

 of plants was necessary before they could be properly classified. 



Ttzigsohn will be the first to receive our attention. His opinions 

 varied in regard to the spermagonia (38). He was inclined to be- 

 lieve that they were parasitic fungi, abnormal spore-organs, apo- 

 thecia or even parasitic lichens. Later (41) he expressed it as his 

 opinion that the spermagonia were the antheridia of lichens analo- 

 gous to those of mosses, and the spermatia, the spermatozoa. Still 

 later (42) he states as the result of the study of Pannelia -parietina 

 that the gonidia "of lichens which are reproduced from gonidia," 

 are the female organs and the spermatia the male organs, and that fer- 

 tilization of the gonidia takes place outside of the thallus. Plcnro- 

 coccus, UlothriX) and other algae were supposed to be unfertilized 

 gonidia enabled to lead an independent existence. 



Of much more value were the investigations of Tulasne. He 

 gave the first somewhat exact description of the morphology of many 

 lichens (97 ) . Especially valuable are the accompanying illustrations 

 of sections of the thallus, apothecia and spermagonia. This author 

 proposed the term spermagonium for the small structures upon the 

 thallus, and spermatia for the minute rod-like bodies within the sper- 

 magonium. He was also the first to demonstrate that the spermatia 

 are formed on sterigmata, and that they do not have autonomous 

 movement. As to the function of the spermagonia he believed that 

 they were peculiar reproductive organs, physiologically closely re- 

 lated to the apothecia. He was also the first to call attention to the 

 " pycnids " and the " stylospores. ' 



Lindsay likewise did some excellent work in the morphology of 

 lichens. In his prize essay he presents a communication in regard to 

 the morphology of spermagonia and pycnidia. As to their function 

 he is inclined to the belief that they are analogous to male repro- 

 ductive organs. Lindsay has also given us a very interesting and 

 popular history of British lichens. 1 This excellent little work con- 

 tains good illustrations showing the morphology of the thallus, 

 apothecia and spermagonia ; it gives the history of lichenology, the 

 uses of lichens and diagnoses of the more prominent forms. 



Schwendener, whom we shall mention more particularly in the 

 next period, now began his interesting studies of lichens (79). He 

 made a careful research on the morphology of the majority of known 



1 Lindsay, W. L. A popular History of British Lichens. London. 1856. 



