91 



Cells small, 2-2-| times longer than their diameter, 

 cylindrical or subcylindrical, with a very slight median 

 constriction ; semicells commonly gradually but very 

 slightly attenuated to the apices, which are broad and 

 truncately rounded ; cell-wall with A^ery delicate longi- 

 tudinal striolations ; chloroplasts with one large pyre- 

 noid and many longitudinal ridges. 



Zygospore unknown. 



Length 44-61 ^; breadth 21-28 ^ 



ENGLAND. Cumberland ! Westmoreland ! (Hiwfi). 

 Common in the upland districts of Yorks. (up to 

 2,000 ft.) ! Surrey ! Cornwall ! 



WALES. Penmaenmawr, Y Foel Fras, Llyn Idwal, 

 Llyn Bochlwyd, Glyder Fawr (at 2,700 ft.), Llyn-y- 

 cum-ffvnon, and Snowdon, Carnarvonshire ! 



t, 



SCOTLAND. Sutherland ! , Ross, Inverness ! , Aber- 

 deen ! , Kincardine, Forfar ! , Perth ! , Stirling, Argyll, 

 Arran (Boy $ Bi-ssett). Lewis, Harris, and Benbecula, 

 Outer Hebrides ! Orkneys ! Shetlands ! 



IRELAND. Galwav ! Kerry ! Donegal ! Shores of 



/ e/ 



Lough Keagli ! Londonderry ! Down ! Dublin and 

 Wicklow (Archer). 



GCOIJT. Distribution. France. Germany. Austria. 

 Switzerland. Lapland in Russia. India (forma). New 

 Zealand. Azores (var.) United States. 



This species is somewhat variable, but we see no reason 

 >r gi vino- 

 form of it. 



for giving- the name "var. LundeUii" to the most abundant 



18. Penium phymatosporum Nordst. 

 (PI. VI, figs. 9-11.) 



pTiymatosporvm Nordst. Desm. Ital. 1876, p. 26, t. 12. f. 1; J<-.-h. 

 New and Bare Desm. 1885, p. 35, t. 2o4, f. 11 ; Ccoke,Brit. Desm. 1886, 

 p. 40, t. 17, f. 8. 



Cells small, about 2J- times longer than their 

 diameter, subcylindrical, unconstricted or with a very 

 slight median constriction, very gradually and very 

 slightly attenuated towards the apices, which are 



