The English flora - SeaweedAfrica

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230 LICHENES. [hidiu
c. Thallus shrubby, rounded, usually much branched, mostly erect.
a. Solid. Apothecia globose, filled ivith black powder (cistula) or
solid.
FAM. XVI. SPHiEROPHORE.E.
34. Isidium. Ach. Isidium.
Thallus crustaceous, spreading, adnate, bearing solid, erect
branches (or podetia ?). Apothecia orbicular, convex, at length
subglobose, solid, terminal upon the podetia and more or less
sunk in the extremity, so as to leave a border of the substance
of the podetium.—Name, lag, a kind of coral, and s/bog,form f
from the resemblance of the podetia to some kind of coral or
coralline.—The situation of this genus is very doubtful ; for
the majority of the ramifications are so short and so combined
as almost to constitute a fiattish warted crust, while the portions
that bear the fructifications are considerably elongated. 1
1. I. lutescens, Turn, and Borr. (yellowish Isidium); thallus
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tartareous thin cracked into tumid areola? greyish with a filmy
zonate margin, podetia very abundant minute very short yellowish
almost concealing the thallus. Turn, and Borr. Lick.
Brit. p. 87. Lepraria lutescens, Ach. Meth.—E.Bot t. 1529.
Lepra lutescens, Hoffm. PI. Lick. p. 100. t. 23.
f. 1, 2 Lichen
lutescens, Hoffm.—Isidium phymatodes, phragmeum, Ach.
f3.
Syn. p. 282.
Trunks of large trees, but not common ; in Surrey, Sussex, Suffolk
and Essex.— I have followed the able authors of Lichenographia Brit.
.• in making this a species of Isidium though without the fructification
the plant appears to be altogether a Lepraria, and the apothecia have
neyer been found in Britain.
2. I. coccodes, Ach. (granulated Isidium); thallus tartareous
thin cracked into somewhat tumid convex areolae greyish with
a filmy zonate border, podetia abundant some scattered and
some clustered in patches simple and branched of nearly the
same colour as the crust, apothecia brown immarginate. Turn,
and Borr.—Ach. Syn. p. 283. Turn, and Borr. Lick. Brit,
p. 89. Lichen coccodes, Ach. Prodr.—E.Bot. t. 1511.—