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(Dicks. 1790) and L. Hildenbrandii—the latter of which, it is now said, 
is really entitled, as the original Lichen saturninus, Sm., 1788, to the 
name of the former — is, carefully examined, enough perhaps of itself to 
open anew the question of the distinctness of these lichens; and no un- 
important light is thrown upon its solution by a similar consideration of 
his L. Menziesii. This last, a name only (‘Smith msc.’) as respects 
Acharius, who expressly notes it as otherwise unknown to him, was recog- 
nized much later, upon what authority does not appear, in a Chilian 
lichen, by Montagne, and is now cited (Nyl. 1. ¢.) as a native of various 
regions of South America (Mandon Pl. Boliv. n. 1715, pro p! Lindig 
Herb. N. Gran. n. 2546!) of the Cape of Good Hope (Herb. Kwnz.!) of 
the Himalaya (Hook. & Thoms. Herb. Ind. Or.!) and of China (Nyl. 
l.c.). It will be safe probably to add to these Japan (C. Wright!) and 
Hawaii (H. Mann!) from which the common lichen of the United States 
is scarcely separable; and L. Menziesii will come thus to stand for L. 
nyochroum or saturninum of authors, as it occurs in regions exotic to 
Europe: neither of the other two plants named above being recognized by 
Nylander except as European. But taking into account only the South 
American lichens, of the determination of which we are tolerably certain, 
it is still beforehand likely that a plant generally so similar as the New 
Granada lichen above cited, to the European, and with so wide a range, 
should vary into forms even nearer to, if in fact separable from the latter; 
and such seems, if I may rely on my material, to be the fact. If the 
plant now exhibits, in tropical regions, a somewhat similar exuberance to 
that which characterizes Z. Trenelloides similarly conditioned, even these 
states are well comparable with more northern ones; and fade out, as the 
atmospherical conditions change (in the Himalaya, in Japan, &c.,) into 
others quite undistinguishable: and the ‘species’ comes thus at last to 
rest, so far at least as the fertile forms go, on no other definable character 
than rather larger spores; exactly as with the largest tropical states of 
L. Tremelloides as compared with inferior, especially northern ones. 
Our more common, lead-coloured North American lichen has thus been 
referred to L. Menziesit, only to pass, with it, into too near affinity with 
the European LZ. myochroum. The latter occurs however in two marked 
forms, now generally reputed species. One of these (ZL. saturninum 
(Dicks.) Nyl., is admitted (Th. Fr. Lich. Arct.) to be common to Arctic 
America and Europe; and it is interesting that Scherer (Spicil.) referred 
the lead-coloured American state, which he had from the Carolina moun- 
tains, to the other—his var. saturnina—which is L. Hildenbrandii 
(Garov.) Nyl. What then, we have next to ask, is the probable value of 
this discrimination? The question might hardly suggest itself to North 
American lichenists, who, if they followed Scherer in recognizing a 
southern form of the species, would probably not differ from him in 
assigning to it a merely subordinate rank. But such judgment is worth 
little without revision from a point of view which shall also include 
