NOTE ON LECIDEA DIDYMOSPORA. 143 



said, " it is as mncli entitled to a specific place as Lecidea gemi- 

 nata" I beg to state that such a conclusion by no means logically 

 results from the premises. For though a normally 2-spored plant 

 {L. geminatci) is regarded as specifically distinct from a normally 

 8-spored one {L. pet7'cea), it does not follow that another 2-spored 

 plant should also be regarded as specifically distinct from a nor- 

 mally solitary spored species (L. sanguinaria). In fact, the occur- 

 rence of solitary spores in L. geminata tends rather to show how 

 unwarrantable in the other case would be such a separation. 



So much, then, for Lecidea didymospora, Strn. In " Grevillea," 

 iii., p. 25, Dr. Stirton is so good as to hint that I may be able to 

 suggest an analogous, if not identical name for his Lecidea subre- 

 tusa, on the grounds of " the scattered state of the literature of the 

 subject !" I venture to suggest that it may possibly be Lecidea 

 accedens (Ain.). Probably, however, it is only a mere and pro- 

 bably old state (such I have gathered on Ben Lawers) of the very 

 variable Lecidea suhuletonmi, which, in some conditions, presents 

 spores "-which in size and shape" are not different from those 

 described by Dr. Stirton. As to the other " new species" des- 

 cribed pp. 33-37, I might readily "conjecture," with more or less 

 probability, the identity of several with old and well-known species. 

 Such conjectures, however, in the absence of the specimens them- 

 selves, I prefer not to indulge in at present. I shall therefore 

 content myself with stating that Lecidea scidulata, Strn., :^ L. 

 consentiens, Nyl., with th alius coloured such as it rarely occurs on 

 Ben Lawers, and that Xi/logi-apha sca^ihoidea, Strn., = X. paral- 

 lela, var. pallens^ Nyl., such as I observed it some years ago in the 

 neighbourhood of Dalwhinnie and elsewhere. 



With regard to Lecidea alpicola, Schser., which Dr. S. seems to 

 intimate that he had gathered for the first time in Great Britain on 

 Ben Lawers, this was omitted from my Licli. Brit. Emnn. simply 

 because I had not then gathered it on Ben Nevis, and previous 

 records of the plant were too doubtful. L. galbida was not " in- 

 serted in its place," but on information since ascertained to be 

 erroneous, that it had been gathered on that mountain by Dr. Lind- 

 say. Mr. Leighton therefore did right in omitting L. galbula 

 altogether from his valuable Lich. Fl. L. alpicola, previously 

 recorded by me as an addition in " Journ. Bot.," was inserted by 

 Leighton not " in its place," but because in the Nylanderian arrange- 

 ment followed it comes next in order. There was thus no mistake 

 in the matter. A mistake, however, is committed by Dr. S. when, 

 in censuring Mr. Leighton for speaking of the spores of L. alpicola 

 as being colourless, he says that "when mature they are of a 

 beautiful green colour, merging ultimately to brown." Here the 

 censor must himself be censured, for the fact is they ultimately 

 become " blackish !" 



