OP ARTS AND SCIENCES. 183 



the time at least (whatever may be intended in tlie future), of the more 

 difficult and important consideration in full of the points of agreement 

 with known forms, — is simply to minimize the value of species; and 

 can have but one I'esult, and that only a disastrous one, on the future 

 of Licheiiology. 



Usaea sulplmrea (Miill.), Th. Fr., is the same certainly as Neuro- 

 pogon meluxanthiis (Ach.) Nyl. But it is not questioned that the 

 lichen named is indigenous to both the Arctic and Antarctic zones, and 

 was first published from the former under the name first cited above. 

 The fact that the Arctic condition is less luxuriant than the other can 

 make no difference in the application of the universally recognized rule 

 of nomenclature, which overrides individual preferences, and is intended 

 to. But my reviewer continues tliut '* Tuckerman also seems to imply 

 that Neuropogon Taylori (Hook, fil.) cannot rightly be discriminated 

 from the preceding." It was, perhaps, rather more than implied. Hav- 

 ing, for many years, been in receipt of specimens of the yellow Usnea 

 of the polar regions, especially of the antarctic forms, it became a matter 

 of some interest to me to determine the U. 2\(yh>ri, considered (it 

 should appear) by Dr. Taylor to take the [)lace, in Kerguelen's Land, 

 of the older species ; but not likely to be restricted to the island. The 

 endeavor was in vain, and even in Dr. Kidder's large Kei'guelen col- 

 lection there was nothing that appeared separable from the [)l:int of the 

 Falkland Islands, as there was nothing in either Taylor's or Nylauder's 

 diagnosis of U. Taylori satisfactorily to distinguish it. 



Pannaria Taylori, Tnckerm. ubi sup., Oct. 187.5, which was de- 

 scribed from a specimen without name in the Taylor lierbarinm, is the 

 same, it fully appears, as the P. placodiopsis, Nyl, of the ".Journal of 

 Botany," of November of the same year. But Mr. Cronibie is now 

 able t(» show, from Dr. Hooker's specimen, that the lichen is Lecanora 

 dichroa, Tayl., which would hardly be guessed from the description. 

 That certainly seems to indicate an areolate, oidy sub-effigiirate plant, 

 of much the type of Lecanora gelida ; and by no means this marked 

 Pannaria. 



'^^ Pannaria glaucella, Tuck., sp. n. = Amphidium molyhdoplacum, 

 Nyl." I cite this definite statement as it stands in Mr. Crombie's paper. 

 It seems, however, from the evidence of the same gentleman, that there 

 is no doubt at all that the plant is new ; or that it was published by one 

 writer, under the specific name glaucella in October, and by another 

 under that of molyhdoplaca, in tiie following November. This should 

 appear to settle the name of the species ; but what of the g>'nus, and 

 where is it defined ? The only reference to it that I can discover is in 



