THE ALG^E OF GUEKNSEY. 



BY ME. E. D. MARQUAND, PRESIDENT. 



The popular term " Seaweed " is so universally understood 

 that it is unnecessary to define what is meant by it. Thou- 

 sands of persons who have very vague notions indeed as to 

 what lichens are, and who have probably never heard of 

 Liverworts and Scale Mosses, know in a moment what sea- 

 weeds are. These " flowers of the ocean " have become 

 favourites with multitudes of men and women who have 

 neither leisure nor inclination to master the technicalities of 

 science, serving to recall many a pleasant holiday spent at the 

 seaside, — because in a greater degree than any other tribe of 

 plants they may be easily and permanently preserved, so as to 

 retain for an indefinite period the graceful forms and lovely 

 tints which so pre-eminently characterize them. 



They belong to that immense class of flowerless plants 

 known in science as Alga ; but it is well to bear in mind that 

 although all seaweeds proper are algae, all algae are not sea- 

 weeds in the strict sense of the word. Under this term is 

 comprised a very large section composed of plants inhabiting 

 ponds and streams, bogs and ditches, and in fact wet places 

 generally ; these are called the Fresh Water Algae. And 

 further there are included two extensive divisions of purely 

 microscopical plants, of which the Desmids are confined to 

 fresh water exclusively ; whilst the Diatoms are found all 

 over the globe in a living state wherever there is pure stand- 

 ing or running water of any kind, fresh, salt or brackish. 



It is not my intention to say anything about the Diatoms 

 to-day, because I read a paper on the subject before this 

 Society twelve months ago, and a list of 322 species indigen- 

 ous to Guernsey was published in the last number of our 

 Transactions. What I wish to do now is to direct your 

 attention to the three other groups : the Seaweeds proper, 

 the Fresh Water Algae, and the Desmids. And I may just 

 mention in passing that these present lists will complete the 

 task I set myself to accomplish six years ago, viz. : the 



