A GENERAL SURVEY 17 



certain seaweeds are eaten, but whether they 

 are very nice or nourishing is an open question. 

 A few of the fiowerless plants provide fodder 

 for animals. The most important instance is 

 that of the so-called Reindeer Moss — which, by 

 the way, is really a hchen ; this enters largely 

 into the sustenance of the four-footed friends 

 of the Laplanders. Certain kinds of seaweed 

 yield the useful drug iodine, and most of the 

 common sorts when placed on the land act as 

 reasonably good fertilisers. With this paltry 

 list one is almost at an end of the direct 

 benefits which mankind receives from the 

 fiowerless plants, apart from the beneficial 

 kinds of bacteria which have already come 

 under notice. 



Unhappily, the list of harmful results arising 

 from fiowerless plants is much more formidable, 

 though it is chiefiy restricted to one group, the 

 fungi. Many of these wreak the most fearful 

 havoc amongst crops, and are known to farmers 

 and gardeners under the names of " rust " and 

 " mildew." One of the most familiar, and at 

 the same time extremely serious, fungus pests 

 is that known as the "Wheat Rust." The life 

 history of this plant is very compHcated, and 



