CRYPTOGAMIA Algce.
G en. Char. Seeds in black, linear, sessile, simple or
branched, bordered clefts, in an uninterrupted crust.
Spec. Char. Crust leprous, tartareous, uneven, whitish.
Clefts immersed, crowded, somewhat powdery,
zigzag, simple and branched, with an elevated
border from the crust.
Syn. Opegrapha serpentina. Ach. Meth. 29. Schrad.
Journ. ann. 1801. fasc, 1. 79.
Lichen serpentinus. Ach. Prod. 25.
S e n t from Yarmouth by Mr. Turner, who is by no means
convinced of its being permanently distinct from 0. pulveru-
lenta. Acharius rests the character of the present species on
its thicker and tartareous crust; but we know this circumstance
to be variable in some Lichens, as sulfuscus; and Mr.
Turner has traced intermediate varieties between the crusts of
these two Opegraphce. A difference in the habit of the fructification
is also mentioned, and perhaps not without foundation,
but the clefts of 0. pulverulenta are extremely variable.
In this they are more frequently unbranched, and more irregularly
sprinkled over the crust. We beg leave to remark
that the arrangement of these organs, and their more or less
parallel position, are much affected by the mode of extension
pf the bark. Nevertheless, as 0. serpentina has been deliberately
kept distinct by such first-rate cryptogamists as Acharius
and Schrader, we have thought best to publish a figure of
it, being the first that has appeared.