2791
V E R R U C A R I A Dufourii.
Dufourian Verrucaria.
CRY PTOGAMIA Lichenes.
G e n . C h a r . Tubercles of a different substance from
the thallus, simple, convex, not expanding, but
furnished with a central pore, and inclosing a
somewhat gelatinous nucleus.
S p e c . C h a r . Crust determinate, tartareous, smoky
grey,somewhatpruinose,level; atlengthminutely
tessellated. Tubercles large, prominent, mostly
truncate, black.
S yn. Verrucaria Dufourii. De Cand. FI. Fr. ed 2.
v. 2. 318. Duby, Bot. Gall. 646. Fries, Lick.
Reform. 433.
V. pyrenophora. Ach. Lich. Univ. 285. t. 4. f . 3.
Syn. 94.
^ 8 ^HE discovery of this Lichen, in 1833, at Chedder, where
it abounds on calcareous rocks on the summit of the hill
above the cliffs, has enabled us to distinguish it more decidedly
from V. epipolcea, t. 2647, f . 3. in the account of
which it is dubiously mentioned by the Acharian name*.
Its differences may be collected from the following description.
It was first named by De Candolle after the Chevalier
Dufour, who observed it on walls at Meudon. It has since
* We are now convinced that the species before us, not that alluded to
under V. muralis, t. 2647. ƒ. 2, is the true V. Dufourii. From Fries’s descriptions,
our V. epipolcea appears to be his V. conoidea (V. rubella of
“ Chaubard” and of Duby,) rather than his V. argillacea, to which last
“ chiefly ” he refers the Acharian V. epipolcea.