COSMAK1V.AI. 197 



A]y. Orkneys and Shetlaiids, 1905,, p. 20; Borye,, Beitrage Alg\ Scliwc- 



deii, 1906, p. 31. 



C. prsemorsum a. gaUiciun Eacib. Desni. Xowe, 1889, p. 89. 

 (.''. ji'-ra>mot'su.m b. scaitdinavicum Eacib. 1. c. p. 89. 

 UrsincUa >rtemorsa Ivuntze, Eevis. gen. plant. 1891, p. 92o. 



Cells rather under medium size, slightly longer than 



o / o 



broad, very deeply constricted, sinus narrowly linear 

 with a slightly dilated extremity ; semicells widely 

 pyramidate-truncate or truncate-subsemicircular, basal 

 angles broadly rounded, sides convex, apex widely 



truncate or subtruncate, often very slightly convex ; 



j <j 



apical angles rounded ; cell- wall somewhat unevenly 

 granulate, each lateral margin with about 8 granules, 

 those nearest the apex being as a rule decidedly larger 

 than those at the basal angles, apex smooth, with a 

 number of irregularly scattered granules of somewhat 

 variable size within both lateral margins and apex, in 

 the centre of the semicells with a very variable number 



/ 



of large granules irregularly disposed, and sometimes 



O O t/ X 



intermingled with a few smaller granules, or occa- 



o o ^ 



sionally with minute intergranular scrobiculations, 



.' O 



generally with a fairly clear area on each side of the 

 isthmus. Side view of semicell subcircular or widely 

 obovate-circular. Vertical view elliptic, ratio of axes 

 about 1 : T7, with the grannies at the middle on each 

 side rather more prominent than the others. Chloro- 

 plasts axile, with two pyrenoids. 



Zygospore (immature r) ellipsoid, with a few scattered 

 mamillate elevations, each terminated by a short blunt 

 spine. 



Length 47-55 /x ; breadth 43-51 p. ; breadth of 

 isthmus 14-16 /x; thickness 23-29 /x; length of zygo- 

 spore with spines 63 p, breadth 52 p.. 



ENGLAND.- -Cumberland ! Westmoreland ! (Hixxett). 

 Lancashire ! \V., X., and E. Yorks ! Cambridge- 

 shire ! Warwickshire ! Gloucestershire ! Middlesex ! 

 Surrey ! Kent (zygospore from Keston Common) ! 

 Hants ! (Bennett). Devon! Cornwall! 



WALES. Llanrhwchwyn near Llanwrst, near Llan- 



/ 



beris, Snowdon, Capel Curig, Moel Siabod, Llyn 



