LICHEN saxicola,
Radiated Wall Lichen.
CRYPTOGAMIA Algee.
Gen. Gh a r . Male, scattered warts.
Female, smooth shields or tubercles, in which the
seeds are imbedded.
Spec. Char. Crust circular, finely lobed, somewhat
imbricated, pale sulphureous green; the lobes cut,
crenate, zigzag and entangled. Shields central,
crowded, flatfish, tawny brown, with a pale uneven
border.
Syn. Lichen saxicola. Ach.. Prod. 104.
L. muralis. Dicks. Crypt, fasc. 1. 11. With. v. 4. 2 9 .
Hull. 292. Relh. 460. Sibth. 417- Abbot. 264,
Psora muralis. Hoffm, Pi. Lich. v. 1. 77. t. 16. f . 1,
Parmelia saxicola. Ach. Melh, 191.
very uncommon on sandstone rock$, brick walls,
and loose flinty stones in open situations. On the broad flat
stones with which houses are tiled in Yorkshire, it grows peculiarly
luxuriant, spreading into a circular band a foot or
more in diameter, the centre being entirely obliterated by time.
Most generally it occurs in round patches an inch or twoi
broad, of a pale greenish sulphur-colour, closely attached,
more or less neatly lobed and imbricated according to the
hardness and smoothness of what it grows upon. The crust
is cut into narrow linear segments, closely entangled and in
some measure imbricated, dilated and crenate externally,
smooth, scarcely separable from the stone. Shields small,
crowded, central, sessile, almost flat, rather browner than
the crust, but having a crenate or uneven border of the same
substance and colour as that part. On moist mossy walls is
found a more lax and dilated variety, of which we exhibit
a specimen.
We do not see why Pollich’s name saxicola has been
preferred to the -older and equally suitable one of Schreber,
muralis.
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