14 THE MARINE BOTANIST. 



water-mark^ and in tide-pools^ also in deep water. 

 Frequent on the shores of England and Ireland^ 

 but not found in Scotland. 



PYCNOPHYCUS. 



Name meaning thick sea-weed. 



Root branched. Fronds cylindrical. Recep- 

 tacles cellular^ terminal^ pierced by numerous 

 pores. 



PYCNOPHYCUS TUBERCULATUS.— TU- 

 BERCLED PYCNOPHYCUS. 



Fronds growing* crowded together, from twelve 

 to twenty inches in length, repeatedly forked ; the 

 receptacles are produced at the ends of the branches, 

 and the air-vessels are rarely seen, excepting when 

 the plant grows in deep water. Colour a clear 

 olive. Substance brittle when dry. Perennial. 

 Summer and Autumn. The roots are matted 



