CRYPTOGAMIA Alga;.
Gen. Char. Receptacles cup-shaped, with a torn
border from the crust, powdery, with a fertile
disk beneath.
Spec. Char. Crust orbicular, tartareous, th in , ash-
coloured, cracked ; its circumference indeterminate.
Receptacles orbicular, very small, white,
w ith an elevated margin, and a flesh-coloured
disk.
F o r this also we are obliged to the Rev. Mr. Harriman, who
found it on whinstone in the county of Durham. It has been
thought a variety of the last, (V lactea,) but we presume to
think it as distinct as any other of the genus ; differing from
lactea in the grey ashy colour, and great tenuity, of the crust;
but especially in the margin being indeterminate, extending
itself in dispersed spreading patches, and by no means limited
by a thin shining zoned border, which is essential to the former.
The fructification is copious though small, in minute
white prominent dots. These prove, under a magnifier, to be
orbicular receptacles, with an elevated entire border of the
substance of the crust, and a very distinct, solid, flesh-coloured
disk, covered by a dense layer of very white powder,
which easily rubs off, and the disk becomes visible by means
of its reddish hue.
This species is not mentioned in the Lichenographia BrU
tannica, though perhaps alluded to under Vlactea /3, arena-
ria, p. 69.