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Europe; and there the enquiry is less simple. At first view indeed the 
contrast between 1) the northern, characteristically black-greenish state, 
only velvety beneath, and commonly sterile (Moug. & Nestl. Vog. n. 454, 
a,b. Fr. Swec.n. 299. Scher. Helv. n. 424,500. Anz. Langobard. n. 
292) which represents L. saturninum, and 2) the southern, rufous-glaucous 
condition, rugulose above, and fleecy beneath, and commonly fertile 
(Moug. & Nestl. n. 454, c,d. Schleich. ezs. Scher. n. 423. Mass. Ital. 
n.28. Herb. Krempelh. Anz. Ital. Sup.n.2) which stands for L. Hilden- 
brandii, is so considerable, that we cannot wonder that modern writers 
have agreed in elevating what served only as a subordinate difference in 
the older lichenographers into specific diversity: yet a closer examina- 
tion shall not improbably result in invalidating every character upon 
which this diversity is predicated. As respects colour, though the differ- 
ence noted is clearly appreciable, finding recognition in Koerber, as possi- 
bly also, to some extent, conditioning judgments where it is not expressly 
recognized, little stress is laid upon it by most authors, and neither 
Acharius, Scherer, nor Nylander, take it at allinto account. The fact 
undoubtedly is that in each form, and in Z. Menziesit as well, we have a 
paler, more or less lead-coloured condition, becoming darker, and ulti- 
mately blackening: something however of the difference between brown- 
ish and reddish is certainly suggested by what is perhaps the best colora- 
tion of the two European lichens, and is to be traced also in that of 
the Himalaya, passing there, before blackening, into a fine purplish. I 
observe it here, only in specimens from New Mexico (Fendler). Conced- 
ing then, for what it may be worth, such degree of variation in this 
respect between the northern and the southern lichens, we pass to the con- 
spicuous corrugation of the upper side in L. Hildenbrandii, of which also 
there is no trace in L. saturninum; and here too the same high authori- 
ties agree in an adverse opinion. The distinction, unnoticed by Acharius, 
is given up by Nylander, in his Z. Menziesii,— the Bolivian specimens 
determined by him having a wrinkled surface and the New Granada ones 
being smooth, —and in this he only concurs with Scherer’s judgment of 
the corresponding European states; a judgment since corroborated by 
that of Arnold, to be cited below. It is, as the case is conditioned, quite 
unlikely that the character should really be worth more in Europe, than 
out of Europe. As respects my North American specimens, traces of 
wrinkling only appear in an Alabama lichen (T. M. Peters) and in the 
cited one from New Mexico; both might possibly be referred, as ill-con- 
ditioned states, to L. Hildenbrandii; the latter of them is yet, at the 
same time, scarcely to be distinguished from one of the Himalaya plants, 
referable, it should seem, to L. Menziesit. It only remains to consider the 
various development of the nap of the under side, which enables us to 
discriminate a velvety (brevissime tomentosa) condition from a fleecy one 
(‘fibrillose rhizinosa’) and this difference again is well taken. As how- 
ever the tomentum tends always to pass into rhizine at the base of the 
