SELECTION. ii 



from places where it had previously flourished. 

 It is said that this disappearance is due to the 

 fact that the plant is dioecious, that the male 

 plant only has been imported, and that this 

 dies out after about seven years unless repro- 

 duced from seed. 



The so-called Ribbon Weed {Sparganium 

 ramosum) is an unmitigated nuisance in any 

 stream ; it contains little or no food for the 

 fish, chokes up the water wherever it is once 

 established, is so firmly rooted that to extirpate 

 it seems impossible, and from the fly fisher- 

 man's point of view has the additional dis- 

 advantage of being very tough and sharp on 

 either edge, so that a hooked fish running 

 through it can usually manage to cut the gut 

 and get away. I have thought it well to 

 set out this question in some detail under the 

 heading of " Selection," as indicating clearly 

 which are desirable and which undesirable 

 weeds ; but it may be taken as an axiom that 

 a good head of well-conditioned trout of average 

 size can only be found in a river where the 

 growth of weeds is luxuriant. 



It is desirable that there should be a small Mud. 

 quantity of mud in some reaches of a fishery. 

 It must not, however, be imagined that the 

 filthy slime left by sewage pollution, or the 

 sediment which is ever accumulating on the 



