^~ YMBIOSIS. 



337 



Various species of jjlants 



occurs between plants and animals 

 attach themselves to ani- 

 mals by which they are 

 carried about. The plant 

 is thus aided in obtaining 

 the materials for food, 

 and not infrequently the 

 plant conceals the animal 

 from another which seeks 

 it as prey. In this way 

 certain crabs are hidden 

 by algce attached to them. 

 One of the most striking 

 cases of protective mimicry 

 is that in which an Aus- 

 tralian fish has acquired 

 surface outgrowths which 

 imitate almost precisely the 

 appearance of brown sea- 

 weeds, so that, when quiet, 

 it looks like a stone to 

 which seaweeds had attached themselves. Thus it often 



escapes its enemies, as does the crab with its 



mask of real seaweeds. 



B. Helotism. 



462. I. Fung-i and algae. — Helotism 



exists between fungi and algie, constituting 



^\khe"r"t'/!!X°lt the bodies known as lichens, in which the 



■{nveiopinran^afj^', fuugus is the master and the alga the slave. 



:(^1r;Tii^t'^ (See^ 54^, and fig. 377.) ^ The same 



After eraer. fungus may be found enslaving more than 



one species of alg^e even within the same mycelium. The 



protonema of mosses or even the leaves of some small 



Yi(,. 1,-jfj. — A young clover plant, sltowing tuber- 

 cles, t, on tlie routs. Natural size, — After 

 Go£f. 



