f'LOSTERIUM. 121 



Infus. 1861, p. 748; Rabenh. Flor. Europ. Algar. Ill, 18IJ.S, p. 12<i ; 



Wolle, Desni. U.S. 1884, p. 42, t. (5, f. 19 ; Cooke, Brit. Desm. 188(5, p. 28, 



t. 10, f. 3; West, Alg. W. Ireland, 18!)2, p. 12:5; Roy & Hiss. Scott. 



Desni. 1894, p. 244; Nordst. Index Desm. 1896, p. 85; West A <J. S. 



West, Alg. S. England, 1897, p. 481 ; Alga-fl. Yorks. 19(H), p. 54; 



Alg. N. Ireland, 1902, p. 24. 



Cl. doliolatum Bn'-b. in Cheval. mioroscop. et usage, Paris, 1839, p. 272. 

 ('I. I in-ijiilnlinii Kiitz. Phycol. germ. 1845, p. 132. 

 Cl. dilatutnm Kiit/-. Phycol. germ. 1845, p. 132. 

 Cl. striofiitinn 1>. <;,*t<tl ni Klelis, De.sm. Ostpreiiss. 1879, p. 14. 

 Arthrodia cost at a Kuntze, Revis. gen. plant. 1891, p. 883. 



Cells of medium size, G 10 (commonly 7 or 8) times 

 longer than their diameter, moderately curved, outer 

 margin from 90 to 98 of arc, gradually attenuated 

 towards the apices, which are rounded, truncately 

 rounded, or rounded-conical ; cell- wall reddish-brown, 

 costate, with 6-8 costee visible across the cell ; each 

 chloroplast with 6-7 pyrenoids in one axile series ; 

 terminal vacuoles with numerous moving granules. 



Zygospore globose or ovoid-globose, smooth. 



Distance between apices 340 405 JK,; breadth 48-06 /A; 

 diam. of zygosp. 100-120 p. 



ENGLAND. Cumberland ! Westmoreland ! (Ralfs). 

 W. and 1ST. Yorks! Cheshire (Li <>'/}. Leicester (lloij). 

 Warwick (Tf^s). Oxford! Gloucester (Half*). Essex! 

 Middlesex! Sussex (Ra Ifs). Surrey ! (Ru Ifs). Hants! 

 (Ralfs). Devon! Cornwall! (Ralfs). 



WALES. Fairly general ! 



SCOTLAND. General ! (Roy fy Rissetf). Outer Heb- 

 rides ! Shetlands ! 



IRELAND. Mayo ! Galway ! Kerry ! Donegal ! 

 Dublin and Wicklow (Archer). Antrim! 



Geogr. Distribution. France. Germany. Austria. 

 Hungary. Italy. Norway. Sweden. Denmark. 

 N. and S. Russia. Faeroes. Greenland. United 

 States. 



This is a characteristic species which exhibits a certain 

 amount of variation. The number of costas visible across the 

 cell is usually six, hut there may be as few as five or as many 

 as eight, and occasionally the cell-wall is punctate between 

 the costas. The apices of the cells are generally angularly 

 rounded and are often of a deeper colour than the rest of the 

 cell- wall. 



