INTRODUCTION xxv 



to the Lichens." Earlier still, Nylander 1 , in a paper dealing with cephalodia 

 and their peculiar gonidia, had denounced it : " Locum sic suum dignum 

 occupat algolichenomachia inter historias ridiculas, quae hodie haud paucae 

 circa lichenes, majore imaginatione quam scientia, enarrantur." He never 

 changed his attitude and Crombie 2 , wholly agreeing with his estimate of 

 these "absurd tales," translates a much later pronouncement by him 3 : 

 "All these allegations belong to inept Schwendenerism and scarcely deserve 

 even to be reviewed or castigated so puerile are they the offspring of in- 

 experience and of a light imagination. No true science there." Crombie 4 

 himself in a, first paper on this subject declared that " the new theory would 

 necessitate their degradation from the position they have so long held as an 

 independent class." He scornfully rejected the whole subject as "a Romance 

 of Lichenology, or the unnatural union between a captive Algal damsel and 

 a tyrant Fungal master." The nearest approach to any concession on the 

 algal question occurs in a translation by Crombie 5 of one of Nylander's 

 papers. It is stated there that a saxicolous alga (Gongrosira Kiitz.) had 

 been found bearing the apothecia of Lecidea herbidida n. sp. Nylander adds'? 

 "This algological genus is one which readily passes into lichens." At a later 

 date, Crombie 6 was even more comprehensively contemptuous and wrote: 

 " whether viewed anatomically or biologically, analytically or synthetically, 

 it is instead of being true science, only the Romance of Lichenology." These 

 views were shared by many continental lichenologists and were indeed, as 

 already stated, justified to a considerable extent: it was impossible to regard 

 such a large and distinctive class of plants as merely fungi parasitic on the 

 lower algae. 



Controversy about lichens never dies down, and that view of their para- 

 sitic nature has been freshly promulgated among others by the American 

 lichenologist Bruce Fink 7 . The genetic origin of the gonidia has also been 

 restated by Elfving 8 : the various theories and views are discussed fully in 

 the chapter on the lichen plant. 



Much of the interest in lichens has centred round their symbiotic growth. 

 No theory of simple parasitism can explain the association of the two 

 plants: if one of the symbionts is withdrawn either fungus or alga the 

 lichen as such ceases to exist. Together they form a healthy unit capable 

 of development and change : a basis for progress along new lines. Permanent 

 characters have been formed which are transmitted just as in other units of 

 organic life. 



A new view of the association has been advanced by F. and Mme Moreau 9 . 

 They hold that the most characteristic lichen structures more particularly 



1 Nylander 1869. 2 Crombie 1891. 3 Nylander 1891. 4 Crombie 1874. 



8 Crombie 1877. 6 Crombie 1885. 7 Fink 1913. 8 Elfving 1913. 



9 Moreau 1918. 



