Io8 YORKSHIRE NAtURAUSTs' UNION. 



512. Staurastrum acarides Nordst. 

 Mid U'. — Penyghent. 



N.W.— Mickle Fell. 



This rare species is only known from four other localities in 

 the British Isles, all of which are in Scotland. 



Forma hexagona \Vest. 

 N.W.— Mickle Fell. 



A'ar. eboracense West. 

 N.W.— Mickle Fell. 



5 1 3. Staurastrum sexcostatum Breb. 

 S.W. — Denholme. 



N.W.— Mickle and Cronkley Fells. 



Subsp. productum AVest. 

 Mid W. — Cocket Moss, near Giggleswick. Bog two miles 

 south of Clapham. 



N.W. — Cronkley Fell. Bog near Widdale Beck. 

 N.E. — Pilmoor, near Thirsk. 



514. Staurastrum margaritaceum (Ehrenb.) Menegh. 

 Abundant, more especially in the upland districts ; the com- 

 monest mountain form of this species is a 4-ended one. 



S.W. — Rawcliffe Common. Keighley Moor. 



Mid W. — Adel. Bride Cross, above Farnley Moor. Rom- 

 bald's Moor. Cocket Moss, near Giggleswick. Bowland Knotts. 

 Ingleborough. Penyghent. Whernside. Old Cote Moor. Near 

 Buckden. Oughtershaw Tarn. Cam Fell. Ribblehead. 



N.W.— Mickle and Cronkley Fells. Great Shunnor Fell. 

 Lund's Fell. Mossdale Moor, Widdale Fell. Bog near Widdale 

 Beck. Dodd Fell (at 2,000 feet). Cowgill Wold Moss, Widdale 

 Fell. Baugh Fell. Hunter's Hole, Craydale Moor. 



N.E.— Strensall ! (W. B. Turner). 



515. Staurastrum Arachne Ralfs. 

 N.E.— Strensall (W. B. Turner). 



Genus ARTHRODESMUS Ehrenb., 1838. 



516. Arthrodesmus convergens Ehrenb. 



Trans. Y.N.U., 1899 (pub. July 1901). Bol. .Scries, Vol. 5. 



