117 



ON " PARHELIA MILLANIANA, Stirton." 



On the 5tli November, 1874, Dr. Hugh Macmillan, of Glasgow, 

 sent me a sterile tliallus which he had found growing with Par- 

 melia Icevigata, in Glen Crow, at the head of Loch Long, Argyle- 

 shire, and which both he and Dr. Stirton, of Glasgow, regarded as 

 new and distinct, and to which the latter had given the name of P. 

 31illaniana, in honour of the discoverer, Dr. Macmillan, Dr. 

 Macmillan asked in his letter, "Is there any possibility of its being 

 your P. endochlura, which Dr. Taylor found associated with P. 

 laevigata in Ireland ?" and requested my reply by return of post. 

 I immediately compared Dr. Macmillan's specimen with an 

 authentic specimen from Dr. Taylor himself, gathered by him at 

 Dunkerron, which I have in my herbarium, and found them qmte 

 identical. On the same day, November 6th, I wrote to this effect 

 to Dr. Macmillan. Judge, then, of my astonishment, when on 

 opening the December No. of " Grevillea," I found this selfsame 

 lichen, notwithstanding my careful and communicated identification, 

 described and published as "P. Millaniuna, Stirton," and as^a 

 " species nova .'" Is this advancing or retarding the progress of 

 science ? 



Arthonia lurida, Ach. 



In the same paper Dr. Stirton declares that his Lecidea 

 emphi/sa (which from his description could never be a Lecidea) is 

 identical with Arthonia lurida, Ach. As I have never had an 

 opportunity of examining and comparing Dr. Stirton's lichen, I 

 cannot say whether this be correct or otherwise. But he makes 

 such startling remarks respecting the external and internal structure 

 of A. lurida, that I really must be pardoned if I express a 

 doubt whether Dr. Stirton really knows A. lurida. I have, 

 from time to time, collected and examined scores, nay 

 hundreds, of specimens of A. lurida, but have never detected 

 any character which could by any possibility lead me to 

 question its being a true Arthonia. The internal structure and 

 spores I have invariably found as figured in my " British 

 Graphidese," t. 8, fig. 38, and described in my Lichen-Flora. I 

 have tried the effect of liq. potassfe, but could not perceive any 

 distinct paraphyses, the structure being that of a gelatinoso- 

 concrete mass, as in all other Arthonige, in which the rotundo- 

 pyriformasci are imbedded, as it were, in cavities, carved out of this 

 mass. Such is the structure which all authors whom I have ever 

 consulted attribute to the genus J-/-^/ionm " thalamium paraphysibus 

 discretis nuUis " (Nyl. ^cand. 257) ; " Lamina sporigera grumoso- 

 floccosa paraphysibus destituta " (Korb. Syst. 280). Massalongo 

 does, indeed, say (Ric. 50), " paraphysibus tenuibus ;" bv;t Th. M. 

 Fries, in his Lich. Arctoi, 240, corrects this thus : '" Paraphyses 

 capillares ' de quibus mentionem facit eel. Massalongo (I.e.) non 

 adsunt." Et sic omnes. Nor could I produce any " coerulescent 



