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LICHEN discoideus.
Insipid P ozedery-shielded Lichen.
CRYPTOGAMIA Algce.
Gen. Char. Male, "scattered warts.
Female, smooth shields or tubercles, in which the
seeds are imbedded.
Spec. Char. Crust rugged, bordered, greyish. Tubercles
mealy, white, flattish: at length concave,
with a dilated, torn border.
Syn. Lichen discoideus. Ach. Prod. 28.
L. fagineus. Haffm.' Enum. t. I . f . 5.
L. albescens. Huds. 529.
L. carpineus. Lightf. 807;
Lichenoides candidum et fatjnaceum, scutellis fere
planis. Dill. Muse. 131. f. 18. ƒ . 11.
Variolaria discoidea. Ach. Meth. 14.
T h i s is probably as common as L. fagineus, with which it
has been confounded. The synonym of Dilieniusj generally
applied to fagineus before Professor Acharius wrote, surely
rather belongs to this, and we think we are right also in
quoting Lightfoot, though the carpineus of Linnaeus is a
«very different thing.
The present specimen was sent us from Yarmouth by Mr.
W . Borrer, who observes that the bitter flavour of L. fagineus
is not found in this species. Acharius describes it as most
white when young, but his own specimen, though old, is as
white as possible. The chief characteristic of L. discoideus
seems to be the little elevation of the tubercles, which, after
their powdery contents are discharged", become quite concave,
to which may be added their dilated and expanded margin.
On the trunks of old treqs, particularly in wet weather, this
Lichen is very conspicuous for its whiteness.