ally reddish, brown ; their internal substance of a paler
brown, wax-like, under a glass of considerable power appearing
obscurely dotted. On old timber the crust is sometimes
broken into irregular tumid warts, upon and among
which the apothecia are found variously undulate and flex-
uose (fig. b.).
The synonyms of Ehrhart and Hoffmann are quoted on
the authority of Acharius in his Synopsis ; and, assuming
them to be correct, the original trivial name is preferred.
Acharius tells us that the plant is also Lichen pruinatus of
Persoon in Usteri’s Annalen. The figure formerly given in
English Botany, t. 981, as Lichen impolilus, was probably
taken from a common appearance of Spiloma gregaria
(S.tumidulum Ach.), an extremely variable species, of which
a more perfect state is represented t. 2151.
It is difficult to distinguish this genus by technical characters,
drawn from the apothecia only, from the Solorinoe
of Acharius, which that author originally regarded as Ar-
thonioe, but which differ altogether in the nature of their
thallus. We have no appropriate name for the apothecia
of Arthonia. They differ from the patelluloe of Lecidea,
and from the lirellce of Opegrapha, by the absence of a proper
margin. Lichen lynceus, t. 809. (Arthonia lyncea and
Opegr. notha y. cæsia of the Acharian Synopsis) seems a
true Opegrapha. Meyer has perhaps done well in placing
our O. dendritica and O. Lyellii in a new genus, his Platy-
gramme, to which O. venosa, t. 2454-,* also must belong.
They appear to differ from true Opegraphae by wanting a
proper margin to the apothecia, and they can scarcely be
referred to Arthonia.—W. B.
!
2692. (Fig. 2.)
ARTHONIA luHda.
Lurid Arthonia.
CRYPTOGAMIA Lichenes.
Gen. Char, Apothecia solid, deformed, without a margin,
sessile or immersed.
Spec. Char. Crust obsolete, continuous, smooth, dull
lead-coloured or brownish. Apothecia sessile,
roundish, slightly convex, reddish black.
Syn. Arthonia lurida. Ack.Lich. Univ. 143. Syn. 7.
Spiloma paradoxum. Ach. Lich. Univ. 139. Syn. 3.
JPROBABLY not rare on bark in shady places. The
late Sir Thomas Gage found it on fir-trees in Ireland ; our
specimen grew on holly, on Black Down, Sussex ; and the
plant has been observed on oaks elsewhere in the same
county.
Crust, if present at all, a smooth film, so extremely thin
as to be but doubtfully distinguishable from the surface of
the bark, upon which the plant spreads widely and irregularly,
imparting sometimes a pale-brownish, sometimes a
dark lead-gray tinge. Apothecia numerous, not unlike
minute specks of some purplish-black or very deep blood-
red conserve, irregularly scattered, often clustered and confluent,
superficial, thin, of a roundish but uncertain figure,
flattish, but varying a little in prominence, and rather more