(69) 
but, though its range reaches northward as far as the shores of the Icy 
Sea, has equally failed, hitherto, of detection in North America. L. con- 
finis is readily distinguishable by its cylindrical thallus, and much smaller 
size; it was not however considered to differ in species by Turner (Hist. 
Fuc.) and Hooker remarks that his observations have led him to regard 
it ‘as a mere variety of the preceding, whose different appearance is due 
to a more frequent exposure to a dry atmosphere’ (Brit. Fl.) a view the 
probability of which is certainly not weakened by the failure of Nylander 
(Syn.) to indicate any other than the named points of diversity ——I refer 
here, provisionally, a New England lichen, found by me on rocks beyond 
the tides, but within reach of the spray in storms, at Cape Ann in Massa- 
chusetts, and since, by Mr. Willey, on rocks at least five miles from the 
sea, at New Bedford, which, agreeing in other respects generally with L. 
confinis is yet differenced constantly, and most remarkably, by what seems 
an intrusive, microscopical alga, supplanting almost wholly the proper 
gonimous system of the plant, and, as it were, substituting itself for it. 
These curious facts will be fully exhibited elsewhere. 
Sub- Fam. 2. -EUCOLLEMEI. 
Thallus foliaceus macro- ]. microphyllinus, aut dein crustaceo- 
diminutus, rarissime fruticulosus, collogonidiis 1. glomeratis 1. in 
plerisque moniliformi-concatenatis in pulpam homogeneam filamen- 
tis medullaribus percursam sepius confluentibus. Medulla in infimis 
parenchymatica. Apothecia normaliter lecanorina, nonnunquam 
persistenter globosa. 
The extraordinary modification of thalline structure, which, com- 
meneing in Peltigerei, compels us to recognize two distinct lines of other- 
wise congenerical forms in each of the larger genera of that family, is. 
further conditioned in Pannaria by a precipitate and at length extreme 
degeneration of the foliaceous type. Starting, we may say, like the other 
genera just named, as a normal, frondose group of Parmeliacei, and pass- 
ing like them, into conditions in which the gonimous system is peculiarly 
modified, Pannaria ends in semi-crustaceous states the explication of 
which has proved exceedingly uncertain. From just such crustaceous 
conditions, the real relations of which to degenerant Pannariine forms 
are not seldom doubtful, ascends how another series (Hucollemei) at once 
contrasting with Parmeliaceous Lichens, and yet inextricably bound up 
with them. This new series, in which the structural changes suggested: 
in Peiltigerei, and begun in Pannaria, reach their full development, and 
the gonimous system an ascendency becoming almost. inordinate, is made 
up however, not of well-defined but of most intricately correlated groups ; 
