LICHENS 525 



the shingly beach at Pevensey Bay nearly every pebble above high- 

 water mark is more or less covered with this lichen. 



Gr aphis elegans (PI. XL, fig. i). — Pale cream-colour or greyish 

 white, with numerous straight or curved, rather prominent blackish 

 lines which are in reality the fruit of the lichen. It grows on the 

 bark of various trees, but is perhaps most beautifully developed 

 when growing on the bark of the holly. 



Several closely allied species grow on the bark of trees, and the 

 genus is recognized by the apothecia or fruit-forming, variously 

 curved or branched, black lines on a whitish ground, resembling 

 Arabic writing characters. 



Pannaria rubiginosa (PI. XL, fig. 4). — This beautiful lichen grows 

 on mossy rocks or trunks of trees. 



Coniocarpon gregarium (PI. XL, fig. 6). — This is not a British 

 lichen, but has been found on the bark of imported wood. 



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Lecauora lai taiea 



