No. 22.] [April, 1874. 



drmlUa, 



A MONTHLY RECORD OF CRYPTOGAMIC BOTANY 

 AND ITS LITERATURE. 



NYLANDER ON THE ALGO-LICHEN HYPOTHESIS 

 AND ON THE NUTRITION OF LICHENS, &c. 



Translated by the Rev. J. M. Crombie, F.L.S., &C 



Dr. Nylander, in noticing in the "Flora," 1874, No. 4, two 

 recent pamphlets by Dr. Weddell, makes the following very op- 

 portune observations on several most important matters relating to 

 Lichenology, which with several additional notes, he has requested 

 me to translate for insertion in " Grevillea." The pamphlets under 

 review are : — 



I. — H. A. Weddell, " Les Lichens du massif granitique de Liguge " 

 (Extrait du " Bulletin de la Societe Botanique de France/' 1873). 



II. — H. A. "Weddell, "Nouvelle Revue des Lichens du Jardin public 

 de Blossac, a, Poitiers " (Extrait des " Memoires de la Societe" des 

 Sciences Naturelles de Cherbourg," 1873). 



Since what I have elsewhere written is true, " that truth itself 

 consists in the continual demolition of errors," I have always be- 

 lieved that it tends very much to the interests of science to oppose 

 fanciful or erroneous opinions ; nay, it may legitimately be con- 

 sidered to be one's duty to point out and refute such opinions, for 

 the.progress of science depends not a little upon their subversion. 

 Nothing, indeed, as is evident, is more readily received and propa- 

 gated than erroneous opinions, and, conseqnently, there is so much 

 greater difficulty in opposing their propagation, though we may not 

 on that account depart from the duty. 



The two writings, whose titles are given above, forsaking on 

 certain points the truth and exactness of science, present a handle 

 for some animadversions, of which the following are, I think, 

 especially useful and opportune where they touch upon modern 

 controversies. 



I. 



Here, in the first place, we find (p. 5) these words — " Recent 

 observations introduce to our notice singular relations which exist 

 between Lichens and Alga?," &c. From this it would appear that 

 the author, in his own way, assents to the Schwendenerian hypo- 



