WM, [ 1549 ]
CRYPTOGAMIA Algae,
Gen. Char. Male, scattered warts.
Female, smooth shields or tubercles, in which the
seeds are imbedded.
Spec. Char. Crust thin, powdery, spreading, pale
greenish- sulphur-coloured. Shields sessile, pale
buff, with a powdery edge; at length convex,
rugged, without a border.
Syn. Lichen orostheus. A oh. Prod. 38.
Lecidea orosthea. Ach. Meth. 7 2 .
T h i s Lichen has long been known in England under a name
given to it by Mr. Dickson, but never published, vireseens.
Mr. Turner has found it on trees and pales in Norfolk, and
Mr. W. Brunton on old trees near Rippon, Yorkshire. A
specimen sent by Dr. Acharius on a bit of quartz rock, from
that situation, as it should seem, has the crust interrupted,
with a branched or fibrous appearance. There can, notwithstanding,
be no doubt of the identity of his plant and
ours.
In Mr. Brunton’s specimens here delineated the crust is
continued, widely. spreading, thin, of an uniform pale sulphur
colour, a little greenish when Wet, all over powdery.
The shields are numerous, almost immersed in the powder of
the crust, when young small, flat, of a very pale buff-colour,
with a powdery margin of the colour and texture of the crust;
when arrived at maturity the margin is obliterated, and the
disk becomes somewhat enlarged, convex, rugged or lobed,
with little or no change of colour. In an early state the shields
are supported on short stalks, which are scarcely perceptible
because of the powdery crust.
.ISAM
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