587 



HYDRODICTYON RETiCULATUM. 



By James Burton. 



(Read May 2oth, 1915.) 



Last autumn I had the good fortune to obtain the freshwater 

 alga known as the Water-net, Hydrodictyon reticulatum, or 

 utriculatum, for both names are used. 



It occurred in immense quantity in the lake in Kew Gardens 

 and was brought to my notice by Mr. Traviss, who at the "Gossip" 

 meeting in September told me there was a plant in great amount 

 in the lake at Kew, and that it was like one of those loofahs 

 used in baths it seemed to me a capital description, and I at 

 once realised that it was Hydrodictyon, and visited the scene 

 next day. Prof. West says it is a very rare plant in Britain, but 

 several authors say it is found fairly frequently in the south 

 and south-east of England. I do not know of it having been 

 found at any of our excursions, and though probably known 

 by name to many, it is most likely that few have seen it. I have 

 a page, evidently part of an article, in Dr. Cooke's handwriting 

 which gives some information about it. He savs : " The 

 Water-net is one of the earliest enumerated of the Freshwater 

 Algae in Britain. Its characteristic form enables figures to be 

 instantly recognised, and thus we are without doubt able to 

 assert its presence in 1691, when it was figured in Plukenet's 

 Alma Gestum (PL 2-1, f. 2) and again by Bobart in the 3rd vol* 

 of Morison's Hortus Oxoniensis in 1699. Ray includes it in his 

 " Synopsis " in 1724 as Conferva reticulata, and says that it was 

 found at that time in ditches, about Westminster and Hounslow." 

 Dr. Cooke then gives a number of instances in which it is referred 

 to by various writers, including Hassall in 1845. He then says : 

 ,; Recent localities have not been recorded, in fact it is very 

 desirable that we should know the present stations of such an 

 easily recognised plant, which this year appeared in such quan- 

 tities in a small pond in the pleasure ground at Kew Gardens 



