228 SCYTONEME^J. 



Conf. atrovirens Dillw. t. 25. Lichen pubescens, E. Bot. 

 t. 2318. ; Harv. in Hook. Br. Fl. ii. p. 363. St. atro- 

 virens Harv. in Manual, p. 153. 



Hob. On wet rocks forming the banks to the river 

 Diloris, near Neath, Glamorganshire: Mr. Dillwyn. 

 Mountainous district ; 14 miles west of Aberdeen : Dr. 

 Dickie. On wet rocks above the falls of Aberdylais, 

 Swansea : Gutch. 



This species forms rigid lustreless and very dark tufts ; 

 the filaments are divaricately branched, the branches nar- 

 rower than the stem, and sometimes furnished with two or 

 three secondary ramuli. The larger divisions are dark brown 

 and opaque, the smaller vivid green, their terminations being 

 marked with transverse lines, which indicate the divisions into 

 cells. The dense cartilaginous sheath is most visible at the 

 terminations of the branches. 



2. STIGONEMA MAMILLOSUM Ag. 

 Plate LXVI. Figs. 2, 3. 



Char. Branches incrassated, spindle-shaped, the two inferior 

 thirds densely mamillose on all sides. 



Bangia mamillosa Lyng. t. 25. ; Harv. in Hook. Br. Fl. 

 p. ii. p. 363. Stig. mamillosum Harv. in Manual, 

 p. 153. 



Hob. Rocky bottoms of subalpine rivulets, Appin : Capt. 

 Carmichael. Eagle's nest, Killarney : W. H. Harvey. 

 Mountainous district ; 14 miles west of Aberdeen : 

 Dr. Dickie. 



This forms continuous tufts several inches in diameter, 

 which are less rigid than in S. atrovirens ; the branches are 

 simple, their diameter being greatest in the middle, and beset 

 on all sides, for the two lower threads with mamillae of 

 various sizes, and the cells of which are always cylindrical, 

 and not moniliform. These mamillae as well as the upper 



