524 WILD FLOWEES OF 



Leprarice are extremely common on old trees, and 

 palings, which they stain so freely that they might be 

 called white, green, yellow, black, or sulphur washes. 

 These consist entirely of minute granules, and are 

 therefore the simplest form known of the lichen tribe. 

 The species of Variolaria are known at a distance 

 from the large white circles they form on many trees, 

 with numerous white pustules. V. discoidea and V. 

 faginea are the most common. The latter may be 

 always known from the intensely bitter taste of its 

 spreading adnate thallus. The common Urceolaria 

 (JT.scruposa), often covers sandstone rocks, old crosses 

 in church-yards, towers, buttresses, &c. to a great 

 extent with its hard, thick, grey, crustaceous thallus, 

 scarcely differing in substance from the stone on 

 which it grows, abundantly interspersed with minute 

 rugged hollows, which are its immersed apothecia. 

 CRABBE probably had this species, with Z7. calcarea, 

 Verrucaria rupestris, Lecanora atra, and other saxico- 

 lose lichens in view when describing the appearance 

 of his church tower overspread with 



" The enduring foliage ; then we trace 



The freckled flower upon the flinty base ; 

 These all increase, till in unnotic'd years 

 The stony tower as grey with age appears ; 

 With coats of vegetation thinly spread, 

 Coat above coat, the living on the dead." 

 Many of the old oolitic altar tombs in the church- 

 yards among the wind-blown Cotteswolds, are com- 

 pletely encrusted with a stratum of grey Urceolaria 

 a note of Time written down by moisture, yet more 

 permanent than any inscription. Perhaps the most 

 curious of these armadilloed lichens is the Beomyces 

 rufus, whose granulated crust is at a little distance 



