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. Haematomma 

 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. 



66 



