LICHENS. 1 93 



upon living trees. Though not uncommon, I did not 

 succeed in finding any of them on that occasion ; but on 

 closely examining the bark of the trees, young and old. 

 I did descry stains and markings of most wondrous form. 

 Some seemed like miniature inscriptions in ancient 

 characters, and some like interrupted lines, or irregular 

 dots. There could be no doubt that these were the 

 writing-lichens, and one in particular resembled so closely 

 Greek characters that I named it the Greek writing-lichen 

 (Opegrapha scripta, j%. 6.) 



There was one growing on the bark of the Spanish 

 chestnut, in which the short lines were waved and turned 

 in different directions. The crust was huffish, and the 

 long-shaped fruit was black. The distinguishing pecu- 

 liarity in the fruit of these writing-lichens is the long 

 shape and the depressed mark down the centre. The 

 parasite of the Spanish chestnut was the Variable Writing- 

 lichen (0. varia, Plate XIII., fig. 8) ; and the black 

 Writing-lichen (0. atra, Plate XIII, fig. 9), with its 

 close horizontal lines, decorated the bark of manv young 

 oaks. There are a great number of species in this family". 

 On a subsequent occasion when exploring the grounds 

 about Craig House near Edinburgh, we found the circular 

 patches of the Brain Writing-lichen encrusting the walls 

 (0. cerebrina, Plate XIII, Jig. 12) ; and both there, and 

 in the Highlands we found the Stone species (0. saxatili.-. 

 Plate XIII, fig. 14). The St any, the Eed, and the 

 Birch Writing-lichens are parasites on trees, and grew 

 about Hawkhurst, (Plate XIV., figs. 15, 16). 



"These graphic lichens," says Dr. Murray, "inscribe 



in curious hieroglyphics, yet intelligible character-, en 



x 



