L I C H E N olivaceus.'
Olive-coloured Leafy Lichen.
CRYPTOGAMIA Algce.
Gen. Char. Male, scattered warts.
Female, smooth shields or tubercles, in which the
seeds are imbedded.
Spec. C har. Leafy, creeping, orbicular, brown-olive,
shining, rugged in the centre; brownish and fibrous
beneath: its lobes flat, dilated, cut and dotted.
Shields dark-chesnut-olive, with an indexed unequal
margin.
Syn. Lichen olivaceus. Linn. Sp. P l. 1611. Ach.
Prod. 121. Huds. 532. With. v. 4. 35. Hull. 295.
Relh. 462. Sibth. 325. Abbot. 263.
Lichenoides olivaceum, scutellis lsevibus. D ill. Muse.
182. t. 24. ƒ 77 : also/. 78.
L. crusta foliosa scutellata, pullum. Raii Syn. 72.
Parmelia olivacea. Ach. Melh. 213. Winch, v. 2. 56.
F a R from rare on pales or the smooth barks of trees. It is
often peculiarly conspicuous on the white cuticle of the birch,
and is readily known from all our other creeping or imbricated
Lichens by its shining olive colour, little altered by wet or by
drought. The patches are from 2 to 4 inches broad, sometimes
much granulated and rugged in the central part, and
usually, but not always, besprinkled throughout, as well as
the borders of the shields, with papillary warts. The disk of
the shields is rather concave and uneven, of a more chesnUt
cast than the frond, or their own borders. They are smooth
and even at the back, not rugged like L . corrugatus, t. 1652.