J i y [ 8° 9 ]
CRYPTOGAMIA Alga.
G en . Ch a r . Male, fcattered warts.
Female, fmooth fhields or tubercles, in which the
feeds are imbedded.
Spec. Char. Cruft white, fmooth, uniform. Tubercles
numerous, deprefled, oblong, cprved, rounded at
each end, gray, with a black entire edge.
M e . SOWERBY difcovercd this Lichen about 5 years
jfince, in Hainault foreft, Effex, where it often covers the rugged
bark of old oaks almoft entirely. Mr. D. Turner has
‘ fince obferved it on an oak near Windfor. We have not
met with any figure or defcription to which this plant can be
referred. The plates of Wulfen’s and Hoffmann’s alb6-caru-
lefcens at firft fight Teem to accord with it, but on accurate
examination will be found widely different.
Its cruft is. very white, fmooth, and uniform, fcarcely a hair’s
breadth in thicknefs, clofely applied to the bark, and conforming
to all its finuofities and protuberances. Tubercles,
exceedingly numerous, fma}!, thick-fet, regularly fpread over
the cruft, in which they are partly immerfed. Their form is
various, but generally oblong, curved, rounded at each end,
often kidney-ftiaped; their furface flat or deprefled, grayifh,
with a- narrow, black, fcarcely prominent, margin. Ip time
their whole furface becomes black, and then the margin is no
longer perceptible.
This fpecjes fhould be placed near L. fcriptus and rugofus,
from both which it is however quite diftindt, Its tubercles
are never branched, nor do they ever terminate in acute points;
by which they may be known even in a young ftate, when
they are longitudinally furrowed like the fcriptus.
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