L I CHEH iritirorum.
Yellow Wall Lichen.
CRYPTOGAMIA Algce.
G en. Char. Male, scattered warts.
Female, smooth shields or tubercles, in which the
seeds are imbedded.
Spec. Ch a r . Crust circular, plaited and lobed, close-
pressed, bright yellow. Shields central, crowded,
sessile, flattish, orange-coloured, with a smooth
border like the crust.
S yn. Lichen murorum. Ach. Prod. 101. Hoffm.
Enum. 63.. t. 9. f . 2.
L. flavescens. Huds. 528. Hull. 292. Relh. 459.
Sibth. 324.
L . flavicans. With. v. 4, 25.
L. candelarius (3. Lightf. 811.
L. candelaris. JVulf. in Jacq. Coll. v. 3. 124. t . d . f . 1.
Lichenoides crustosum, orbiculis et scutellis flavis.
Dill. Muse. 136. t. 18. f . 18, A, C.
Psora saxicola. Hoffm. PL Lich. v. 1. 82. t. 17. ĥ 3.
N o t h in g can be more common, nor more obvious, thaii
this golden-coloured Lichen on calcareous rocks and stones,
and the mortar of flint walls. The crust forms circular patches,
closeLy attached to the stone or mortar, furrowed lobed and
crenate in the circumference, but not separable in distinct segments
or leaves. This part especially is of the richest golden
yellow ; the centre is either paler and whitish, or greenish and
olive-coloured. Here the numerous shields are crowded, and
sometimes they alone, scattered and robbed of their crust, remain.
They are small, sessile, with a smooth border of the
substance of the crust, and, like that, infernally white; their
disk is deeper coloured than any other part, flat, at length
rather convex.
There has been great confusion between this well marked
species and candelarius, t. 1794, vitellinus, t. 1792, and ele-
gans, Ach. Prod. 10 2 , nor are we, on the other hand, certain
that some others are truly distinct from it.