122 FLOWERLESS PLANTS 



Lecanoras and the Lecideas. Lecanora tartarea 

 is a plant forming greyish crusts on rocks, which 

 at certain seasons of the year are studded with 

 browTi fruiting bodies. In L. subfusca we have 

 a crust hchen which is very common on smooth- 

 barked trees. The crust is usually of a green- 

 ish grey colour and the spore-bearing bodies 

 are brown. Another frequent crust hchen is 

 Lecidea contigua, a whitish growth, much 

 cracked and frequently sprinkled with black 

 fructifications. The Urceolarias, sometimes 

 common on smooth-barked trees, bear their 

 spores in singular little urn-shaped processes. 



Reference should be made to the so-called 

 " \vriting lichens," which in their manner of 

 growth bear a singular resemblance to hiero- 

 glyphics. The species have been well named 

 Graphis. The plants form a grey film on 

 the barks of trees which are not rough, and 

 the fruit-bearing processes spread hither and 

 thither in the form of dark lines. These are 

 sometimes straight, but on other occasions 

 may be curved ; the general effect is that of 

 a weird kind of writing. 



It is quite easy in the case of many of these 

 crust-Hke Uchens to verifj^ the truth of the 



