to the powdery state of V. biformis than to any other British
Verrucaria ; but the crust differs, and the tubercles of that
plant are larger and of a different structure. V.farrea of
Acharius appears more nearly allied to that species than
to the present. This may possibly have been sometimes
passed over as a small state of Lecidea corticola. It still
more nearly resembles Spilomapunctatum at first sight, but
both crust and fructification seem intrinsically different.
W. B.
2637 (Fig. 2.)
V E R R U C A R I A rudis.
Rugged Verrucaria.
CRYPTOGAMIA Lichenes.
Gen. Char. Tubercles of a different substance from
the thallus, simple, convex, not expanding, but
furnished with a central pore, and inclosing a
somewhat gelatinous nucleus.
Spec. Char. Crust indeterminate, somewhat gelatinous,
thin, continuous, uneven with granulations,
grey or blackish. Tubercles very minute,
prominent, irregularly spherical, very rugged,
dull black.
R a r e l y observed, but extremely liable to be overlooked.
It grows on boarded buildings and on rugged
oaks. Our specimens are from Hurstpierpoint and Al-
bourne, Sussex, and Esher, Surrey.
The crust, which spreads widely, is composed of minute
confluent granulations of a dull dark unpolished grey approaching
to black, with a tinge of brown, paler and some-
what gelatinous in appearance when wet; internally with a
pale dull shade of green : sometimes on oak-bark it is more
solid, often minutely cracked, olive-grey, but still varying
in some parts to almost black. Tubercles copiously scattered,
but seldom crowded, prominent; sometimes brownish
as if veiled by the crust, sometimes naked and more
black, and often a little shining; in both cases irregular
in outline and very rugged: orifice minute and irregular,
often not discoverable. Nucleus pale brown or whitish,
looking gelatinous when wet, and filling the shell; shrinking
but little, often not at all, in drying. The tubercles
are occasionally found, in some parts of the patch, seated on
a dark lead-coloured film, with scarcely any of the brownish
crust about them, as if the thallus were composed of such