289 



THE FEESH-WATER ALG^ OF NORTH YORKSHIRE. 



By William West, F.L.S. 



(Plate 291.) 



The list of species in this paper is the result of a very large 

 number of gatherings from all kinds of localities made in different 

 parts of N. Yorkshire. The material which has proved the best 

 was collected by myself at the end of May, 1888, from scores of 

 places over a wide area on Cronkley and Mickle Fells. I also made 

 gatherings in other parts of Upper Teesdale, as near Winch Bridge. 

 Other good gatherings were made during the last two years by my 

 son, G. S. West (who has also greatly assisted me in preparing this 

 paper) and myself at the following places : — Great Shunnor Fell, 

 Cotterdale, Moorcock Inn to Thwaites' Bridge, Scarborough (espe- 

 cially the ''Mere"), Seamer, Strensall (including places a few 

 miles south, as Warthill), &c. Mr. I. Robinson, of Hertford, also 

 lent me some beautiful slides of Diatoms, which he had prepared 

 from his own gatherings in the Whitby and Pickering district. Mr. 

 J. Beanland, of Bradford, also made some gatherings for me at 

 Muker, Marske (near Richmond), Hoi wick, Middleton, Dalton, 

 Romaldkirk, Reeth, Rokeby, &c. 



An excellent paper on the Fresh-water Algae of Strensall Com- 

 mon was published by my able friend, Mr. W. B. Turner, F.R.M.S., 

 F.C.S., in the 'Naturalist' for December, 1883. In the same 

 Journal for September, 1887, there is another note on the AlgaB of 

 Gormire and Thirkleby by the same writer, and also one by myself 

 on AlgaB at Birkdale Tarn Moss, in the same Journal for August, 

 1889. These three papers, together with the present one, form a 

 fair nucleus to the algal flora of the N. Riding. In the Strensall 

 list 154 species and 7 varieties were enumerated. In our Strensall 

 gathering I have noticed a great number of the species in Mr. 

 Turner's list, but I have only here recorded those not mentioned in 

 his paper. A further record of Cosmarium Regnesi Reinsch and 

 Onychonema Nordstedtiana Turn, was published in the * Naturalist ' 

 for February, 1886. With these two species added to the three 

 lists above-mentioned, there are 191 species and 10 varieties 

 enumerated. In the present article the number recorded is 427 

 species and 20 varieties, of which 300 species and the 20 varieties 

 are additional to those previously on record. The total number of 

 Algae known for N. Yorkshire, as recorded in this article and the 

 others mentioned, is 491 species, with 30 varieties. 



As many districts of the Riding are totally uninvestigated, a 

 considerable number of species will no doubt yet be added when the 

 Riding has been further examined, especially in such genera as 

 Vaucheria and (Edogonium. Where a species is said to be " common," 

 it has been seen from numerous localities, " frequent " being affixed 

 to those species which were found to be fairly and widely distributed. 

 There are several new species and varieties in the paper. Some 

 species that are usually frequent were absent in all the gatherings, 



Journal of Botany. — Vol. 27. [Oct. 1889.] u 



