FUNGI AND LICHENS. 123 



and those also of the oak, nourish another tufted 

 lichen. The filaments are broad and strap-like, 

 flattened, notched, lobed, or slightly branched, and 

 nearly of the colour of the bark. The cups are either 

 scattered over the filaments, or at the tips of the lobes 

 or branches. These are rather large, smooth, and 

 darker coloured. This lichen varies considerably in 

 its general appearance. 



A much more mealy form, found on forest trees, 1 

 has the filaments narrower, very much divided into 

 pointed segments, with the cups much smaller, and 

 rarely developed. It has been stated that this lichen 

 is very palatable when eaten with salt : although one 

 of our commonest species, no one seems to have 

 been induced to try the experiment. Some lichens 

 are edible, as, for instance, that called " Iceland 

 moss," which is not a "moss," but a lichen; and 

 -during voyages to the north polar regions, explorers 

 have had to eke out their food with such lichens 

 as they could find, under the name of rock tripe. In 

 Iceland, and other northern countries, lichens are 

 frequently eaten in times of scarcity. The " Iceland 

 moss " and " reindeer moss " (another lichen) are 

 both found in the British isles. 



The " ash-coloured Ground Lichen," 2 is even now 

 sold by herbalists ; it was formerly celebrated as a 

 cure for hydrophobia. It has a membranaceous frond, 

 or thallus, which spreads on the ground, of a greyish 

 colour, whitish beneath, and giving off little fibrils 

 resembling rootlets. The margin is rounded and 



* R. farinacea. 2 Peltigera canina. 



