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LICHENOLOGICAL MEMOEABILIA, No. 8. 

 By the Eev. W. A. Leighton, B.A. Camb., F.L.S., F.B.S. Ed. 

 On Lecidea trochodes, (Tayl.), Leight. 



The aim and object of every student of natural productions in 

 his researches and investigations ought to be the eliciting and 

 establishment of truth. Nevertheless, notwithstanding the utmost 

 care and careful observation, errors will inadvertently occur. The 

 detection of such errors, from whatever cause arising, only makes 

 the truth shine more clearly and distinctly. The pointing out of 

 such errors ought not to be considered an invidious task ; only 

 let it be done in a courteous and gentlemanly manner. To do so 

 in a sneering and acrimonious spirit and way is derogatory from 

 the dignity of science, and unworthy of a true son of science, 

 since it can only rebound unfavourably against himself. 



Dr. Th. M. Fries, in his " Lichenographia Scandinavica," part 2, 

 p. 531, under Lecidea trochodes, (Tayl.), Leight,, quotes as 

 synonymous and identical the four following lichens, viz. : — 



Rim^daria limhorina, Nyl. Flora, 1868, p. 346. Leight. Lich. 

 Fl., p. 406. 

 - Lecidea inferior/, subgyrosa, Nyl. Not. Sallsk., p. F. et Fl. F. 

 Forh., xiii. p. 339, 



Lecidea inconcinna, Nyl. Flora, 1872, p. 357. 



Lecidea subgyi\dula, Nyl. Flora, 1873, p. 296. 

 with this observation : — " Insignis facillimeque determinata 

 species, quam qui semel vidit, dein mox aguoscat. Vix igitur in- 

 telligitur, cur eel. Nylander iiltimis annis banc saltem quatuor iis- 

 demque diversissimis nominibus designaverit. Expressis igitur 

 verbis declaratum volumus, omnia supra allata synonyma examine 

 niti speciminum autlienticorum.'" 



Dr. Fries further states that the peculiar structure of the»apothe- 

 cium upon which Dr. Nylander founds his genus Rimuluria arises 

 from the circumstance that the paraphyses becoming dead, sub- 

 carbonaceous, and fuscous-black, especially at their apices, form a 

 continuous or partial carbonaceous stratum over the epithecium or 

 disk. But that the apothecia are really lecideine and similar to 

 those observed in several species of the genera Gyrophora and 

 Lecidea, the result of a similar deformation, and that an entire 

 perithecium involving the hymenium is purely imaginary. 



What Lecidea inferior f. subgyrosa, Nyl., and Lecidea incon- 

 cinna, Nyl., may prove to be, I have no means of ascertaining, as 

 I have never seen authentic specimens of those lichens. But I 

 possess a fragment of the original specimen which Dr. Taylor 

 collected on Carig Mountain, county Kerry (preserved in Herb. 

 Borrer. at Kew), and which he published in his " Flora Hiberuica," 

 p. 259, as Opegrapha saxigena var. trochodes. This I showed iu 



