Rock Lichens 
or neutral-tinted, though one finds black, bright yellow, 
cream colour, and various rusty and leaden shades, 
mouse colour, or sometimes pure white crustaceous 
lichens. 
The variety of their tints is very remarkable, though 
to see them properly it is necessary for the eye to be 
only a very few inches from the surface. But when 
one is closely scrutinising lichen-covered rocks, the in- 
teresting point is the colour of the tiny sporecups or 
apothecia, which are always an effective contrast and 
yet in harmony with the body colour. Hzmatomma 
is exceptional in its vivid crimson (against pure snow- 
white), but the reddish-yellow, ghostly pale, or bright 
egg-yellow of other crust forms are always pretty and 
interesting. On rocks even in much exposed summits 
in the Highlands there are also a few of the leafy kinds, 
such as Gyrophora, which looks like a badly made 
rosette of brown paper which has been blackened in 
the fire. 
But most of the leafy rosettes and circular patches of 
grey Physcias, Parmelias, &c., are found on old walls, 
or on the branches of badly grown trees. 
The upright little “cup and trumpet” lichens, 
Cladonia, are mostly white or grey, and have bright 
crimson or rich chocolate-brown sporecups. These 
are very characteristic of dry, peaty ground, and may 
almost entirely cover the turf and the base of the heather 
stems in a dry moor. 
Perhaps the most advanced of them all are the Old 
Man’s beards (Alectoria and Usnea), which give a weird 
and impressive appearance to some ancient pine forests. 
In such old woods one may find the crannies in the 
bark of a very old trunk coloured yellow with another 
rare lichen, whose black pinlike sporecups may be found 
on very careful examination. 
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