LICHENS. 209 



for it adorns walls and tiled roofs as freely as the wall 

 Squamaria does. This lichen also affects trees, adhering 

 to the rutted bark, or encircling the branches of oak or 

 thorn. 



" The yellow moss in scaly rings 

 Creeps round the hawthorn's prickly bough." 



Wordsworth. 



" All the same, ever the same, this outward face of things, 

 Time but toucheth it gently, little the change that it brings ; 

 Here where we sat together, spreadeth the self- same tree, 

 Carved and matted the branches, just as they used to be. 

 Even the rich-toned lichen keepeth its place and form, 

 Mellowing the old gray oak-bark, tinting it sunset warm." 



Chambers's Journal. 



A pretty pale species, the Pearly Parmelia (P. perlata,) 

 was sent to us from Malvern ; Lees, the graceful writer 

 upon Malvern botany, says, " The rocks are hoary and 

 silver grey from an extensive spread of Parmelia Saxatilis, 

 and Perlata ; >: and we can well imagine the glossy fronds 

 of the pearly Parmelia giving a charming variety to the 

 dark silurian rocks of that beautiful district. 



The nineteenth family of lichens is that of the dotted 

 group Sticta, so called from the depressed dots on the 

 under surface of the thallus. The fronds are large, lobed, 

 downy beneath, and quite free, except at the base. 



We have all heard of the " Lungs of the oak ' ' (Sticta 



Pulmonaria, Plate XIV., Jig. 9), but none who have not 



seen it can imagine its striking appearance. Among the 



party on the coach as we passed through the Trosachs, it 



created great interest, all wondered what the '"' strange 



o 



