2597. (Pig. 1.)
Y E 11 R U C A R IA olivacea.
Olive-crusted Bark Verrucaria.
CRYPTOGAMIA Lichenes.
Cen. 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, filmy, continuous,
or slightly cracked, roughish, olive-green. T u bercles
prominent, hemispherical or somewhat
conical, black, slightly rugose; the thallus rising
about their base or investing their whole surface.
Syn. Verrucaria olivacea. Pers. in Ust. Ann. st. 7.
28. t. 3. ƒ. 6. B. a. b. Schrad. Spicil. 108. t. 2. f 1.
Y. carpinea. Ach. Meth. 120. Inch. Univ. 281.
Syn. 88.
O n the smooth trunks of thorns, ash-trees, &c. Specimens
from Schrader and from Acharius justify our references
to those authors; and we quote Persoon on the authority
of Schrader, strengthened by the description in Usteri’s
Annalen. Yet we confess this synonym admits of doubt ;
Acharius referring it to his own V. analepta, (our t. 1848,)
which we now regard as a mere variety of V. epidermidis,
and appearing to have received our present plant from Persoon
himself, with the name of V. carpinea. This is indeed
very closely allied to V. epidermidis. We are led to separate
it chiefly by the more considerable and somewhat rugged
crust. This part is usually, not always, without gloss, and
varies in intensity of hue : sometimes it is almost black. It
spreads, in general, indeterminately, and to a considerable
extent; but crowded young plants have occasionally a narrow
darker edge. The tubercles also afford some distinctive
marks. Their base rarely spreads, or stains the crust around