302 A LIST OF FRESH-WATER ALGiE COLLECTED 



XII. — A List of Fresh-water AlgtB collected in Northumberland 

 and Durham. By Geor&e Stewardson Brady, C.M.Z.S. 



The preparation of a complete catalogue of the fresh-water Algas 

 of our district — a work which I at one time hoped to accom- 

 plish — circumstances have compelled me to give up ; hut it is 

 perhaps desirable to place on record some few memoranda made 

 during the time when I studied these organisms. Localities for 

 several species are given in Winch's "Flora," and notices of 

 the occurrence of others, chiefly by Professor Oliver, may be 

 found in the Transactions of the Tyneside Field Club. Beyond 

 these I know of no local literature of the subject. My own col- 

 lection of specimens — both marine and fresh-water — has been 

 for some years in the herbarium of our Natural History Society, 

 and I believe comprises specimens of most, if not all, of the 

 species mentioned in my lists. 



The subject presents a wide field for study. There is much 

 to be done in working out the life-history of the various forms ; 

 it being beyond dispute that many of those hitherto classed as 

 distinct species are merely stages in the existence of Lichens, 

 Fungi, or other Algae. Until problems of this nature are more 

 fully solved the mere collecting and naming of specimens is a 

 dreary and perhaps a useless task, there being no means of 

 appreciating the meaning of facts of habitat and distribution. 



The following list embraces neither Diatomacese nor Desmidi^. 



Vaucheria. 



Many of the varieties to which distinct specific names are 

 usually given occur abundantly in our district, chiefly in ditches, 

 salt-marshes, and on the surface of damp rocks ; but I do not 

 myself believe in the existence of more than a very few well- 

 marked fresh-water species. Hassall counts thirteen British 

 species. 



Batrachospermum moniliforme, Hass. 



This beautiful species is probably of pretty frequent occur- 

 rence. I have found it abundantly in a mill-stream in Wark 



