SPILOMA microscopicum.
Microscopie Spiloma.
CRYPTOGAMIA Algae.
Gen. Char. Receptacles shapeless, w ith o u t a border,
powdery, in an u n in te rru p ted crust.
Spec. Char. Crust spreading widely, very thin, membranous,
greyish. Receptacles dot-like, very minute,
black, lead-coloured when dry.
Syn. Spiloma microscopicum. Turner and Rorrer
Lich. Brit.'v. 1 . 30.
F o r this new Spiloma we are indebted to Mr. W . Borrer,
who, as well as Mr. Turner, has most liberally allowed us to
quote their unpublished Lichenograpkia Britannica as above.
This plant, “ the most inconspicuous perhaps,” as they
observe, “ of all the vegetables hitherto discovered,” is very
common on boarded buildings, and all timber exposed to the
weather, to which it seems to give the blueish tinge after a
while so universally observable: The crust is so extremely
thin, that it seems merely to bleach the fibres of the wood,
over which it spreads widely, exactly as the crust of Lichen
tartareus, and others like it, over-run twigs of heath and
shoots of mosses, on an infinitely larger scale. The dots of
fructification are so excessively minute, as not to be discernible
without a powerful microscope, yet they stain the fingers with
their fine black powder. When dry they turn blueish, or grey.
There are none of the jointed fibres, found in S. melanopum,
t. 2358.