530 



HUTCHINSON'S POPULAR BOTANY 



can feed. In return the waste products of the Fungus can be again utilized 

 by the Alga. It will be seen that the partnership is not absolutely 

 equitable, for whilst the Alga can live without assistance from the Fungus, 

 the latter is entirely dependent upon the Alga. Where the Lichen grows 

 upon the bark of trees or upon the soil, the Fungus partner may get most 

 of what it requires from the humus, but in the case of species growing upon 

 the vertical face of a rock there can be no question that the Fungus is 



Plw.u c,j,j [E. Step. 



FIG. 680. THE SOLITARY TOADSTOOL (Amanita solitaria). 



A representative example of the Agarics, in which the spore-bearing surface is spread over radiating plates (gills) 



on the underside of the cap (pileus). The hanging frill or ring around the stem was, before the expansion of the 



Toidstool, spread over the gills and attached to the edge of the cap. 



entirely dependent upon the activity of its algal partner. Reproduction is 

 of two kinds : both Fungus and Alga produce spores which set up new 

 partnerships, and brood-buds or soredes separate from the thallus. These 

 consist of one or more algal cells invested by a few wisps of the fungal 

 hyphse. 



The methods of spore-bearing in the Fungi differ greatly, but the spores 

 are mostly formed non-sexually by a cell dividing transversely, the dividing 

 portion rounding and dropping off as a spore. In the moulds (Oomycetes, 



