1898.] 



259 



BI.ATINE HYDROPIPBR, LINN., IN THE 



LAGAN CANAL. 



BY J. H. DAVIESS. 



After frequent searchings, during several years, it has now 

 been my good fortune to meet with Elatine Hydropiper in 

 great abundance in the Lagan Canal, a few paces above the 

 tenth lock, at Tullynacross (about a mile from Lisburn), Co. 

 Down, 23rd September, 1898. 



The bottom of the canal at the place where it occurs is 

 firm and gravelly, and is entirel}^ free from mud. The clear- 

 ness of the water at this particular spot is such that, on a 

 bright day, the plant may readily be discerned from the 

 towing-path, and the more so since there is not much aquatic 

 vegetation be^^ond a little of the alien Elodea ca7iadensisy a 

 plant which, although still occurring in greater or lesser 

 quantity throughout the whole length of the canal, seems 

 year by year to be diminishing. The brilliant September 

 sunshine which revealed E. Hydropiper to my admiration, 

 enabled me to see, perhaps, the extent of the space over 

 which it had spread, an area of several square yards being 

 closely covered by the plant. There were, besides, very 

 numerous scattered tufts for some yards farther along. The 

 plants were remarkably luxuriant, much larger than any 

 herbarium specimens that I had seen, the average stems 

 being three to four inches in length. The examples from 

 other localities are mostly one to two inches, and some even 

 smaller. Seen under the microscope, the curiously curved 

 and sub-coiled seeds, alike as to their form, their colour, whi ch 

 js of very delicately graduated shades of translucent green, 

 and their groups of pitted markings, are objects of singular 

 beauty. 



In the two localities w^here the species had previously been 

 found in the Lagan Canal — at Annaghdroghal, near Lough 

 jNeagh (Dr. Moore, 1837), and at Belfast (Dr. Mateer, 1847) — 

 t is supposed to be lost. Indeed, not having been refound 



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