10 GUIDE TO THE STUDY OF LICHENS. 



simple lens. Meyer's studies were perhaps even more 

 comprehensive than those of Wallroth. He entered 

 into a careful investigation of the structure and meta- 

 morphosis of the thallus and apothecia, the gonidia 

 and spores, the growth and nutrition of lichens and 

 their relation to the substratum. 



Stitzenberger (1862) was perhaps the first to em- 

 phasize the importance of the spore-characters in the 

 classification of lichens. According to this author it 

 is principally the generic distinctions which are to be 

 based upon the spore-characters. Lichens with 

 colored and colorless spores are not to be included in 

 the same genus, nor those whose spores differ in the 

 number or direction of the septa, etc. According to 

 the systematist Kbrber (1865) 1,051 species of lichens 

 had been collected in Germany and Switzerland. Of 

 this number Korber described 272 species as new. 

 Massalonga (1853) made a careful study of the struct- 

 ure of crustose lichens and concluded that the spore- 

 characters as well as the form and structure of the 

 apothecia and thallus should be considered in the es- 

 tablishment of genera. Fries (1861) recognized the 

 importance of the spore-characters but considered the 

 form of the spermatia as of nearly equal significance ; 

 in this he was seconded by other authors. The Eng- 

 lish lichenologist Mudd (1861) rightly objected to this 

 procedure because nothing was known of the function 

 of spermagonia and also because the spermatia were 

 not sufficiently varied in form to be of marked impor- 

 tance in classification. Nylander (1858) more than 

 any other investigator has emphasized the importance 



