AN 
ARRANGEMENT 
OF 
THE NORTH AMERICAN 
LICHENS. 
Trib. L.—PARMELIACEI (Fr.) Eschw., emend. 
Apothecia rotundata, scutelleformia aperta aut raro subglobosa, 
receptaculo thallino hymenium normaliter discoideum excipulo pro- 
prio plerumque indistincto receptum marginante. 
It is perhaps not surprising that the marked particularism which has 
characterized the study of Lichens for the last thirty years should have 
tended to obstruct, or at least to embarrass those who during this period 
have sought to comprehend the system as a whole. And it is scarcely 
too much to say that with whatever acuteness of minute investigation 
and wealth of new material of illustration the later systematists have 
adorned their conceptions, they are far yet from having succeeded in 
invalidating the general argument which binds together, in its grand 
outlines, the system of Fries. Especially does this appear to be true of 
the distinction between near and remote affinities (Fr. Syst. Myc. L., 
p. xiv.; Lich. Hur. p. 198) and of the reasoning upon which the great 
bulk of his Parmeliacei is brought together, and at once distinguished 
from and related to his Lecideacei. Vast as are these assemblages, they 
are well defined: which is more than can be said of a large part of those 
which have been meant to supplant them. And if this difficulty of satis- 
factory characterization must be admitted to perplex some of the best 
efforts of recent lichenographers, there is not a little, we shall venture to 
affirm, in ‘modern’ lichenology, which fails to reach the level of thought 
of a Fries or an Eschweiler, on account simply of its limitations. 
For reasons to be elsewhere given at length, the Collemci are restored 
here, as by Eschweiler (Lich. Brasil.) to the position to which their fruit- 
