2612. (Fig. 1.)
V E R R U C A R I A psoromoides.
Leafy Bark Verrucaria.
CRYPTOGAMIA Lichenes.
Gen. Char. Tubercles of a different substance from
the thallus, simple, convex, not expanding, bat
furnished with a central pore, and inclosing a
somewhat gelatinous nucleus.
Spec. Char. Scales between tartareous and leafy,
small, crowded, somewhat imbricated, appressed,
lobed, waved, tumid, olive-green, with slightly
elevated, crenate, whitish, downy edges ; underside
black and spongy. Tubercles immersed,
nearly globular, pale, except the slightly prominent
blackish-brown apex.
P r o b a b l y a rare species. As far as we are aware, it
has been found only on elm-bark at Hurstpierpoint, and on
ash at Beeding, Sussex. With the single exception of
V. pulchella, t. 2602. f g . 1, which occurs almost invariably
on moss, not on the bark itself, no other leafy, or even frus-
tulose Verrucaria has been observed to grow on trees.
It forms irregular patches, of a very uneven surface, and
an inch or two, or often much less, in width, composed of
crowded, variously tumid, undulated and contorted, sometimes
confluent scales, of irregular figure, and cut at the
edges into rounded lobes, which vary in depth, and are
usually again crenate. Although thin they are somewhat
tartareous; their internal substance is white, with a narrow
layer of green; their surface, dull olive-green when wet,
browner, with more or less of a grey and pruinose appearance,
when dry. It differs from its nearest affinity, V. pallida,
t. 2541, in its less truly imbricated and more appressed
mode of growth, the edges only of the scales being slightly