THE MARINE BOTANIST. 311 



trae, north of Ireland. Tufts three to six inches 

 long ; soft and lubricous } of a dark green colour. 



C, You7igana, Grows on rocks, &c,y near high 

 water-mark ; first discovered by Mr. W. W. Young, 

 near Dunraven Castle, Glamorganshire. Filaments 

 an inch long, tufted straight, of a bright green 

 colour. ^' Articulations variable in length, at first 

 cylindrical, afterwards becoming contracted in a 

 bead-like manner." 



ULVACEiE.— ULVA TRIBE. 



Green or purple, marine or fresh water algae, 

 composed of small polygonal cells, forming ex- 

 panded membranes, or membranous tubes ^ very 

 rarely arranged in filaments. — Harv, 



The marine plants comprised in this tribe have 

 thin membranous, often expanded fronds, of a flat 

 irregular form, or sometimes hollow and tubular. 

 When examined under the microscope, the cells of 

 the surface appear arranged in regular squares, like 



