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LICHEN contiguus.
Glaucous crow de d-jhielde d Lichen•
CRYPTOGAMIA Alga.
Gen. Char. Male, fcattered warts.
Female, fmooth fhields or tubercles, in which the
feeds are imbedded.
Spec. Char. Cruft glaucous-white, tefiellated and
granulated. Shields cluttered, deprefled, fiattith,
angular, black, with a narrow, black, elevated
margin.
Syn. Verrucaria contigua. H o ffm .F l.G e rm .v .i. 184.
F O U N D by Mr. D. Turner on old brick walls about Yarmouth,
and by Mr. Sowerby in fimilar fituations at Kennington,
Surrey., Specimens from Germany tliow it to be the Verrucaria
contigua of Profeffor Hoffmann, which Dr. Acharius in
his Prodromus combines with our L. concentricus t. 246, and
Hoffmann’s V. cicatricofa, pantherina and tigrina, under one
fpecies called by him lapicida. To this union we can by no
means affent. L. concentricus appears to us perfectly diftin£t
from contiguusr not only in the Concentric arrangement of its
fhields, but in their regularly fmaller fize, concave figure, and
thicker whitifh margin, as well as in the purer white of the
cruft. Of this V. pantherina and tigrina appear from _ the
figures, PI. Lichenofa 1t. 57, to be varieties. _ V. cicatricofa
feems to be given by Hoffmann himfelf as a mere variety of
that now before us. - . .
This has been obferved with us upon bricks only, which it
clothes in large patches of a greenifh or glaucous-white tartare-
ous cruft, cracked or teffellated all over, and a little granulated;
at the edge fometimes blackifh, fometimes feathery, but thefe
circumftances are far from general. The fhields are numerous,
more or lefs crowded or cluttered together (as they advance
in age) into patches or lines, and thus rendering one another
very angular. Their difk is depreffed, at length a little convex
and rugged, black, furrounded by a fharp thin elevated margin.
The cruft is fometimes red within.
L. confluens is nearly allied to this, but its blue or blackifh
gray cruft and more prominent fhields feem to keep it diftinft.