CRYPTOGAMIA Algce.
Gen. Char. Male, scattered warts.
Female, smooth shields or tubercles, in which the
seeds are imbedded.
Spec. Char. Crust brownish grey, cracked, bordered
and intersected by dark serpentine branching lines.
Shields scattered, sessile, black, flat, with a wavy
margin of their own substance, but somewhat paler.
Syn. Lecidea rivulosa. Ach. Meth. 38.
I t seems strange that a Lichen so frequent as this is in rocky
countries should not have been described by British writers.
Our specimens from Mr. W . Borrer and Rev. H. Davies exactly
accord with what Dr. Acharius sends for his Lecidea rivulosa,
as well as with his description of that species. Perhaps it
may be the fusco-ater of our authors, a Lichen for which any
thing of a blackish or brownish cast has been occasionally
exhibited.
The common crust is generally compounded of several
different individuals crowded into one, and their black undulating
edges joined together make several branching lines, but
this character is not by any means confined to the present
species. Its surface is hard, minutely cracked and tessellated,
of a smoky grey, the inside white, of no considerable substance.
Shields scattered, sessile, not immersed nor depressed,
rather small, coal-black and flattish in the disk, their border
elevated, wavy, seldom quite so black as the disk, sometimes
much paler and brownish. A crop of small young shields is
always interspersed among the larger ones,
J737