THE CANADIAN POND- WEED 15 



Anacharis of the Cam came to be identified with the 

 Elodea of Canadian lakes, and the murder was out 

 the sprigs thrown out of the professor's dressing- 

 room had found a congenial home in an English 

 river. Moreover, the newcomer soon spread beyond 

 the hospitable bosom of the Cam. Getting into the 

 canal system, it threatened to bring to a standstill 

 the traffic, which was of vastly greater importance 

 in those days than it is now; so that an opinion 

 gained ground in commercial circles that either the 

 professor, or his housemaid, or both of them, should 

 be put to a violent and painful death. One circum- 

 stance alone seemed to mitigate the disaster. Elodea 

 canadensis is a dioecious herb, bearing, like the 

 aucuba and holly, male and female flowers on differ- 

 ent plants. The professor's specimens happened to 

 be all of the masculine gender, therefore no seeds 

 could be produced. It is true that this irrepressible 

 weed has the property of breaking itself into in- 

 numerable fragments, each one of which may grow 

 into a huge continent of vegetation ; but the lakes 

 and streams of Great Britain are not contrived on a 

 scale to support the prodigious growth which might 

 ensue on a periodic discharge of fertilised seed. 

 Hitherto Elodea has been known in British society 



