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regions of the White Mountains; as also in islands of Behring’s Straits 
(Mr. Wright).——P. rhodocarpa, Koerb. (e Th. Fr. Varicellaria micro- 
sticta, Nyl.) is an inhabitant of Arctic America (Nyl.). 
Sub-Fam. 3.—URCEOLARIEI. 
Apothecia pJus minus urceolata. 
Referred here ex affinitate, as Hymenelia, Krempelh., to Aspicilia, 
and that to Lecanora; however the characters should appear now to 
indicate other dispositions. But Thelotrema and Gyalecta are sometimes 
sufficiently lecanorine; and Urceolaria, which is but ill-separable from 
the rest, is placed with Lecanorei by almost common consent. The group 
affords by far the most evident points of passage of the scutelleform 
apothecium into the Lecideaceous; and plainly touches even the Verru- 
cariaceous; genera and clusters referable to it having been commonly 
assigned by authors to each of the latter tribes. We have here in short 
the thallus of Parmeliacei reduced finally to a minimwm; and as com- 
plement to this degeneration, a remarkable diversity in the always aber- 
rant apothecia, and complexity in the spores. 
Dirina, the carbonaceous hypothecium of which may be taken, as by 
Fries (8. O. V.) for an inchoate proper exciple, is representative of Leca- 
nora in the present sub-family; and is placed indeed with EHulecanorei 
by both Koerber and Th. Fries. But Gyalecta, though, as typified by 
G. rubra, sufficiently lecanorine, appears, as a genus, to offer no uncer- 
tain indications of relationship to the coloured series; as if in fact it were 
a mainly northern, decolorate analogue of the mainly southern, and typi- 
cally coloured Thelotrema: and its lecanorine significance should suggest 
therefore an analogy rather with Rinodina. The predominance of the 
coloured spore-type is indeed evident generally in this group of anoma- 
lous genera; and Urceolaria may perhaps properly be regarded as repre- 
senting its real centre. While taking hold of Lecanora, on the one hand, 
this genus almost touches Gyalecta, on the other; and, not to speak of 
the obvious bearing, in the latter direction, of Urceolaria actinostoma, it 
is observable that U. Valenzueliana, Mont., is without doubt a Gyalecta; 
as U. seruposa, bryophila took finally the same position with Acharius. 
And, once more, Urceolaria comes exceedingly near to Thelotrema; and, 
with the latter, offers the same tendency to pass into compound condi- 
tions, which, anticipated by a pregnant instance, already cited, in Leca- 
nora, has found its full expression in Pertusaria. 
From Urceolaria diverges then, on this side, Thelotrema, in the same 
series; and, on that, Gyalecta. And at each extreme of the group, we 
find the similar and correspondent sub-types, — Conotrema, and Gyrosto- 
mum ; wherein Parmeliaceous character all but disappears. 
