COSMARIUM. 169 



Geogr. Distribution. France. Belgium. Germany. 

 Austria and Gralicia. Hungary. Italy. Portugal. 

 Norway. Sweden. Denmark. Bornholm. Finland. 

 N. Russia. Faeroes. Greenland. Nova Zembla. 

 New Zealand. Australia. E. Africa. Azores. United 

 States. "W. Indies. Brazil. Paraguay (var.). Pata- 

 gonia. 



C. tinctum is distinguished from both C. bioculatum and 

 C. tenue by its proportionately longer cells which are not so 

 deeply constricted. The semicells are more broadly elliptic, 

 the sinus is more open,, and the cell-wall is generally of a pale 

 yellow or yellow-brown colour. The subquadrate form of the 

 zygospore is also characteristic of the species. 



It is a widely-distributed species and can sometimes be 

 obtained in quantity in collections from boggy districts. 



The cell-wall is not invariably tinted, colourless individuals 

 being' occasionallv met with. Wille has described a form 



t 



from Norway (vide ' Norges Ferskv. Alg./ 1880, p. 36, t. 1, 

 f. 22) in which the cell-wall is very delicately punctate, 

 and Borge reports the occurrence of the same form in 

 Greenland. 



Nordstedt has described a trigonal form from New Zealand, 

 in which the vertical view is triangular with rounded angles 

 and slightly convex sides (vide ' Fresh w. Alg. N. Zeal./ 1888, 

 p. 61, t. 3, f. 16). 



Var. intermedium Nordst. (PI. LXI, figs. 19, 20.) 



C. tinctum Ralf s, var. intermedium Nordst. in Botan. Notis. 1887, p. 162 ; 

 Fresliw. Alg. N. Zeal. 1888, p. 61, t. 3, f. 17 ; De Toni, Syll. Alg-. 1889, 

 p. 9-13 ; Borge, Chlorophy. Norska Finmark. 1892, p. 13 ; West, Alg. 

 Eng. Lake District, 1892, p. 725. 



Semicells with the sinus not narrowed towards the 

 apex; vertical view with a slight tumidity at the middle 

 on each side ; cell-wall often colourless. 



Length 11-15 /n ; breadth 10-12^; breadth of 

 isthmus 6-8 ^ ; thickness 8-9 p. 



ENGLAND. Borrowdale, Cumberland ! 



Geogr. Distribution. Norway. New Zealand. 



This variety is intermediate in character between C. tinctum 

 and C. aspherosporum . 



