27 



on the genera of lichens and tieir relationships, 1 which is, however, 

 unsatisfactory, because the author did not seem to have any clear con- 

 ception of genera. Leighton's manual of English lichens 2 has no 

 commendable features : the spore measurements are quoted ; his 

 diagnostic terminology is a peculiar mixture of English and Latin. 

 Korber's and Nylander's methods of classification were referred 

 to in the previous period. Hue published a list of exotic lichens, 3 

 from which it is safe to estimate that nearly five thousand species 

 and varieties were known at the time. Of this number some are 

 no doubt duplicates. It must be remembered also that a host of 

 varieties, sub-varieties and forms were described. It is at present 

 impossible to state the actual number of authentic species. 



Schwendener and his followers uniformly agreed to classify li- 

 chens as fungi. To this the systematists objected very strongly. 

 Naturally, they also objected to Schwendener's theory as to the true 

 nature of lichens. In fact, all through this period we find the mor- 

 phologists and physiologists pitted against the systematists ; the 

 former earnestly endeavoring to get at the life-history of the various 

 lichens, the latter refusing to recognize the discoveries made by the 

 former and continuing the work of arbitrary classification. The 

 work of Jatta 4 deserves special mention. He precedes the descrip- 

 tions of the lichens of southern Italy by a discussion of the anatomy 

 and biology of lichens, and adds a number of colored plates illus- 

 trating the principal morphological characters. It is not complete, 

 but it is a work contributing much to the scientific evolution of li- 

 chenology. 



The use of lichens in the arts, in medicine and in the household 

 was still continued. Great improvements were made in the method 

 of using the various lichens in the dye industries. For further par- 

 ticulars the student is referred to three little works on the uses of 

 lichens by Magnin' 5 , Henneguy 6 and Porcher 7 . As far as the medi- 

 cinal uses of lichens are concerned we find that the allopathic school 



1 Tuckerman, E. Genera Lichenum. Amherst. 1872. 



2 Leighton. W. A. The Lichen-flora of Great Britain, Ireland and the Channel Is- 

 lands. Shrewsbury. 1879. 



3 Hue\ A. M. Lichenes Exotici. Paris. 1892. 



4 Jatta, A. Monographia Lichenum Italiae meridionalis. Trano. 1S89. 



5 Magnin, Dr. A. Les Lichens utiles. Lyon. 1877. 



6 Henneguy, Dr. F. Les Lichens utiles. Paris. 1883. 



'Porcher, F. P. The Medicinal, Poisonous and Dietetic Properties of the Cryp- 

 togamie Plants of the United States. New York. 1854. 



