W. WEST AND G. S. WEST : ALGA-FLORA OF YORKSHIRE. 65 



270. Euastrum incavatum Josh. & Nordst. 



N.W. — Mickle Fell. Length, 35 ju, ; breadth, 20 /x; breadth 

 of isthmus, 4^5 /x. 



271. Euastrum pectinatum Breb. 

 S.W. — Cullingworth. 



Mid W. — Adel Bog (with zygospores). Wigton Moor. 

 Malhani Tarn. Cocket Moss, near Giggleswick (with zygos 

 pores). Bog two miles south of Clapham. 



N.W. — Mickle and Cronkley Fells. 



N.E.— Strensall ! (W. B. Turner). Pilmoor, near Thirsk. 



S.E. — Riccall and Skipwith Commons. 



272. Euastrum gemmatum (Breb.) Ralfs. 

 N.W.— Mickle Fell. 



N.E. — Pilmoor, near Thirsk. 



273. Euastrum verrucosum Ehrenb. 

 S.W. — Rawclift'e Common. 



Mid W.— Bramhope (W. B. Turner). Ilkley (W. H. Dikes). 

 Malham Tarn. 



N.E. —Strensall! (W. B. Turner). Pilmoor, near Thirsk. 



274. Euastrum insulare (Wittr.) Roy 1883. [Syn. E. 



biiiak \!ix. !ns!ilare\Nittr. 1872; Cosiiiiiriiim insulare 



Schmidle 1894]. 

 N.W.— Mickle Fell. 

 N.E. — Pilmoor, near Thirsk. 



275. Euastrum crassicolle Lund. 

 N.W.— Mickle Fell. 



Genus MICRASTERIAS Ag., 1827. 



276. Micrasterias oscitans Ralfs var. mucronata 

 (Dixon) Wille. [Syn. J/i mucronata (D'won) Rabenh.]. 



N.W.— Cronkley Fell. Lund's Fell (iy. 1898). 



277. Micrasterias truncata (Corda) Brdb. 



This is the most generally distributed species of the genus in 

 Yorkshire, but it is by no means common ; it seems to prefer 

 peaty Spkagnum-^ools. 



