CRYPTOGAMIA Alg<z.
G en. Char. Seeds in black, linear, sessile, simple or
branched, bordered clefts, in an uninterrupted crust.
Spec. Char. Crust smooth, membranous, pale olive.
Clefts prominent, turgid, crowded, curved, obtuse,
greyish and powdery, with an elevated, white,
powdery border.
A s far as we can discover, either from the specimens or
descriptions of Dr. Acharius, this is a species unknown to
him, and we have named it in honour of its discoverer, Charles
Lyell, Esq., who found it on the rugged bark of trees in the
New Forest, and to whom we have frequently been obliged
for rare cryptogamous specimens.
This Opegrapha ranges near pulverulenta, t. 1754, and
serpentina, t. 1755. Its crust is remarkably smooth, and
almost waxy in appearance, of an uniform pale olive green.
The clefts are numerous and crowded, mostly simple, sometimes
branched, various in length, curved, obtuse or rounded
at each end, very prominent, their disk broad and convex,
hard, black, but clothed with a grey or whitish powder.
Their border is extremely peculiar, being thick, perfectly
white, and powdery, quite different in texture, surface, and
colour from the crust whence it seems to originate.