210 THE MARINE BOTANIST. 



under surface, concentrically joined. Fructrfica- 

 tion : warts scattered over the upper surface of the 

 frond containing' tetraspores. 



PEYSSONELIA DUBYI.— DUBY'S PEYSSO- 

 NELIA. 



^' Frond one or two inches across ; at first^ orbi- 

 cular ; afterwards, irregularly lobed ; membrana- 

 ceous, thin, adhering- closely by its under surface, 

 which is clothed with short radicles to the surface 

 on which it grows. Colour dull-brown red. On 

 old shells, stones, &c. ; on scallop banks in ten to 

 fifteen fathoms water. Shores of the British 

 Islands not uncommon." — Harv. 



GYMNOGONGRUS. 



Name signifying naked wart-like swellings^ in allusion to the 

 appearance of the fruit in this genus. 



Frond cylindrical or compressed, horny, much 

 branched. Structure very dense. Fmctification : 



I 



