FUNGI: THE LICHENS 



alga Nostoc, with cells like a chain of beads, has been found to be 

 a component of many of the gelatinous lichens. When the spores 

 of these lichens are germinated in the presence of these algae, the 

 mycelial threads coil around the algae, envelop them, and finally 

 a complete lichen thallus is developed which ultimately bears the 

 fruit bodies and asci. 



439. Uses of lichens. As mentioned above, the "reindeer moss" 

 in the arctic regions is eaten by the reindeer. In lower latitudes 

 where it is abundant it is often used as packing material to protect 

 furniture or frangible wares. Some arctic lichens (Cetraria), 

 called " Iceland moss," are used for food by grinding them and mix- 

 ing them with ground wheat. Others which contain purple or 

 blue or crimson pigments are used for making dyes called " archil," 

 also orchil or cudbear. This lichen (Roccella tinctoria] grows on 

 rocks in the Canary and Cape Verde Islands. Litmus paper is 

 made from the litmus dye prepared by treating orchil with soda 

 or potash. 



440. The life history of the sac fungi which produce the fruit 

 bodies (perithecia, or ascocarps, a more general term) as a result 

 of a sexual act can be represented as follows, starting with the 

 mycelium as the plant. Plant asexual spores Plant asexual 



spores Plant ^ / ascocarp ascospore Plant, 



etc. , abbreviated as follows : P asp P asp P ^ ^ ^> asc 



sp P, etc. Where the asexual spores are not formed in the life 

 history they would be omitted from the formula. 



