We shall refer briefly to some of the other morphologists of 

 this period. Mohl 1 made a careful study of the spores of crypto- 

 gams, including those of lichens. Korber" studied the gonidia 

 and in the main verified the conclusions of Wallroth. He also made 

 observations in regard to the reproduction and growth 3 of lichens. 

 Korber's system of lichens * has no commendable features, his 

 diagnoses being usually based upon macroscopic examinations. 

 His orders, genera and species correspond to those of Massalongo. 

 One thousand and fifty-one species of lichens are described as oc- 

 curing in Germany and Switzerland. Two hundred and seventy- 

 two species are described as new ; from this it may safely be con- 

 cluded that many species are only imaginary. The modern lichen- 

 ologist will find it impossible to recognize many of the species from 

 his descriptions. In passing it may be stated that this criticism will 

 apply to the greater number of systematic works issued during this 

 period as well as in the previous periods. The results of Mas- 

 salongo's 5 studies were of considerable importance. This author 

 concluded that the spore-characters, as well as the form and structure 

 of the apothecia and thallus, should be considered in the establish- 

 ment of the genera. It is, however, generally conceded that many 

 of his species and some of his genera were poorly founded. Fries 6 

 also recognized the importance of spore-characters in generic dis- 

 tinctions and in addition considered the form of the spermatia and 

 sterigmata of importance in classification. It was, however, left to 

 Stitzenberger (91) to point out the real value and significance of the 

 spore-characters in the classification of lichens. He believed that in 

 general it was necessary to consider the number of septa in the 

 spores as well as their direction. Lichens with spores differing in 

 the number of septa are not to be included in the same genus. He 

 believed that the spores were equal in importance to the flowers and 



'Mohl, H. Einige Bemerkungen iiber die Entwickelung und den Ban der Sporen 

 der cryptogamischen Gewachse. Flora, 16 : 32-46,49-63,65-73. 1833. 



2 K6rber, G. W. De Gonidiis Lichenum. Berlin. 1839. 



3 K6rber, G. W. Bemerkungen iiber individuelle Fortpflanzung der Flechten. 

 Flora, 24: 6-14. 17-32. 1841. 



4 Korber, G. W. Syste'ma Lichenum Germaniae. Breslau. 1855. Parerga 

 Lichenologica. Breslau. 1865. 



5 Massalongo, A. Recerche sulP anatomia dei Licheni crostosi. Verona. 1852. 

 Memoiree Lichenografiche. Verona. 1853. Monografia dei Licheni blasteniospori. 

 Venice. 1853. 



6 Fries, Th. M. Genera Heterolichenum Europaea recognita. Upsala. 1861. 



