W. WEST AND G. S. WEST: AT.GA-FLORA OF YORKSHIRE. 213 



1007. Nitzschia vivax W. Sm. 

 S.E. — Near Stoneferry (G. Norman). 



1008. Nitzschia dissipata (Kiitz.) Grun. 



[Syn. ? N'. minutissima W. Sm.]. 



Mid W. — Roundhay (W. B. Turner). Baildon. Hawksworth 

 Springs. Malham Tarn. 



N.W.— Mickle Fell. 



N.E.— Whitby. Seamen Rievaulx Abbey. Strensall (W. B. 

 Turner). 



S.E.— Near Hull (G. Norman). 



Var. media Van Heurck. 

 Mid W. — Hawksworth Springs. Penyglient. 

 S.E. — Market Weighton. 



1009. Nitzschia Sigmoidea (Ehrenb.) \V. Sm. 



S.W. — Abundant in the Bradford, Halifax, and Keighley dis- 

 tricts. Cusworth and Hatfield districts; Firsby reservoir; 

 Rossington (M. H. Stiles). Askern ; Hatfield Chase (J. M. 

 Kirk). Roche Abbey (J. N. Coombe). Doncaster. Wibsey. 

 Allerton. 



Mid W.— Malham Cove (J. M. Kirk). Arthington. Bolton 

 Woods. Staveley Dam, near Knaresborougli. Whernside. 



N.W.— Dodd Fell. Mickle and Cronkley Fells. 



N.E. — Seamer. Near Scarborough. Malton. Carlton Bank. 



S.E. — Beverley. Routh. Market Weighton. Skipwith Com- 

 mon. Cottingham; Risby Pond; Wawne ; Haltenprice; Spring 

 Ditch ; Beverley (G. Norman). 



10 ID. Nitzschia vermicularis (Kiitz.) Grun. 

 S.W.— Hatfield district (M. H. Stiles). 



lOTi. Nitzschia Brebissonii W. Sm. 



Mid W. — Gordale. 



S.E. — Near Stoneferry (G. Norman). 



1012. Nitzschia Sigma (Kiitz.) W. Sm. 

 S.W.— Goole (J. Harrison). 



Bot. 5— N 



