THE THALLOPHYTA 309 



729. Teleutospores are thicker-walled than uredospores. Explain. 



730. Can you suggest why it is that fleshy fungi are often so good to 

 eat? 



731. What conditions favor a luxuriant growth of nuishrooms antl 

 toadstools? 



732. Of what advantage to the fungus is the production of the 

 "toadstool" type of fruiting body? 



733. What are the advantages of the gills, pores, and teeth connnonly 

 present in the fruiting bodies of the fleshy fungi? 



734. What is the advantage of the "bracket" form of fruiting body? 



735. Of what use to the stink-horn fungus is its carrion-like odor? 



736. In general, what insects do you think are the commonest carriers 

 of fungus spores? Why? 



737. In a lichen plant, what is the advantage gained by the fungus 

 and what by the alga? 



738. "Slavery" is the term sometimes used to describe the relation 

 of alga to fungus in the lichen plant. Why is "slavery " perhaps a better 

 term than "symbiosis" or "parasitism?" 



739. How different in general is the substratum on which lichens 

 grow from that which supports algae or fungi? 



740. Lichens particularly like rough surfaces to grow on. Explain. 



741. Since algae and fungi are both usually best developed in a moist 

 environment, how does it happen that lichens will often thrive in dry 

 situations? 



742. Lichens are greener when moist than when dry. Explain. 



743. The vegetative body of a lichen is more thin and thallus-like 

 than that of most fungi. Explain. 



744. Aside from their small size, why do you think it is that the algal 

 members of most lichens are either Cyanophyceae or Protococcales? 



745. What conditions must be present before an ascospore produced 

 by a lichen plant can give rise to a new lichen plant? 



746. Of what importance are lichens in nature? 



747. What other instances do you know of, aside from lichens, where 

 fungi become intimately associated with green jjlants? 



