230 SCYTONEME^. 



cohering in tooth-like fascicles. Cells very short. Stride 

 strongly marked. 



Calothrix interrupta Carm. MS. C. interrupta Harv. in 

 Hook. Brit. Fl. p. ii. p. 368. ; Harv. in Manual, p. 158. 



Hob. On mosses and lichens, Appin : Capt. Carmichael. 

 Turk's Cascade, Killarney ; and Toberniorey in the Isle 

 of Mull: W. H. Harvey. Machynlleth, N. Wales: 

 Mr. Rolfs. Aberdeen : Dr. Dickie. 



" Filaments about a line in length, of a glaucous green 

 colour, united into close erect tufts, spreading over the moss, 

 thick, tapering, cohering at the base, and sometimes through 

 their whole length. Internal mass here and there interrupted, 

 leaving short pellucid spaces resembling articulations. Striae 

 close and conspicuous." Carm. MS. 



This species is certainly much more naturally placed in the 

 genus Stigonema than in Calothrix. Owing to the compact- 

 ness of the cells they do not exhibit the dotted or monili- 

 form arrangement of the other species a difference surely 

 not generic. The colour is a light glaucous green. 



5. STIGONEMA MINUTUM Hass. 

 Plate LXVII. Figs. 3, 4. 



Char. Filaments minute, erect) rigid, flexuous, fastigiate. 

 Branches short. Cells or rather sporules in the principal 

 filaments numerous, in the branches in single series. 



Scytonema minutum Ag. S. minutum Harv. in Hook. 

 Brit. Fl. p. 365. ; Harv. in Manual, p. 155. 



Hob. On rocks and crustaceous lichens ; common in al- 

 pine districts, Appin : Capt. Carmichael. Caroigataha 

 near Caher, and at Killarney : W. H. Harvey. 



" Plant either spreading in a black suborbicular crust or 

 scattered in little tufts, filaments erect, minute, closely packed, 

 olivaceous; branches irregular, obtuse, ascending. "Harv. 



Not a very well marked species. 



